The Complete Guide to Residential Extensions in the UK

Transform Your Home: Expert Insights on Single Storey, Double Storey, Garden, Basement, Swimming Pool, and Loft Extensions

The question usually starts the same way: do we move, or do we extend? For many homeowners, the answer increasingly points towards staying put and extending. The reasons vary. Maybe you love your neighbourhood but need more space, perhaps moving costs have become prohibitive, or you simply can't bear to leave a home you've made your own.

But here's the thing about extensions: they're not just about bolting on extra rooms. The best ones transform how your entire home works. They change how light moves through your spaces, how your family moves through the day, how you connect with your garden. Done well, an extension should feel like it was always meant to be there.

This guide walks through six distinct approaches to extending UK homes. We'll cover everything from the ever-popular single storey rear extension through to more ambitious projects like basement conversions and swimming pool buildings. The aim isn't to overwhelm you with technical jargon, but to give you a clear-eyed view of what each type involves: the opportunities, the challenges, the regulatory hurdles, and the design decisions that separate mediocre extensions from exceptional ones.

If you're considering an extension for your property, explore our portfolio of completed extension projects to see how we've transformed homes across the UK, or learn more about our approach to residential design.

1. Single Storey Extensions: Rear, Side, and Front

Walk into almost any British kitchen and you'll see why single storey extensions have become so popular. Many of our homes, particularly those terraced and semi-detached houses built in the early to mid-20th century, have kitchens that feel like afterthoughts. Small, dark, cut off from the garden. A single storey extension can completely change that dynamic.

The appeal is straightforward. You gain substantial space without the structural complexity of building upwards, the disruption tends to be more manageable, and many qualify for permitted development (though we'll come to the details on that). Rear extensions create those sought-after open-plan kitchen-dining-living spaces. Side extensions solve the problem of narrow, awkward rooms. Front extensions (less common, admittedly, because planning can be tricky) can transform entrance halls or reception rooms.

Spatial Dynamics and Flow

Here's where many extensions fall down: they add square footage but don't actually improve how the house works. You end up with a new room that feels tacked on, disconnected from the rest of your home. The real skill lies in creating something that feels inevitable. Like it was always meant to be part of the original building.

Start by watching how your family actually uses your home. Where do people naturally gather? What routes do you take through the house dozens of times a day? A good extension enhances these patterns rather than fighting them. Sightlines matter too. Being able to glimpse from one room into another creates a sense of spaciousness, even when floor areas are modest.

When you knock through that back wall to create an open-plan space, you're not just making a bigger room. The trick is defining zones within the openness. Drop the floor level slightly to mark out the seating area. Use a change in ceiling height between kitchen and dining zones. Different flooring materials can subtly signal transitions. The goal isn't one vast undifferentiated space. It's creating distinct areas that still feel connected.

Side extensions need particular care. You're often dealing with narrow existing rooms: galley kitchens, corridor-like dining rooms. The extension can't just widen things; it needs to rethink how that whole side of the house works, connecting front to back properly. Get it right, and what was an awkward bottleneck becomes genuinely usable space.

Understanding how to create seamless transitions between spaces is fundamental to successful extension design. For deeper insights, read our guide on spatial planning in home extensions or explore open-plan living design principles.

Maximising Natural Light

There's a world of difference between adding space and adding genuinely pleasant space to live in. Light makes that difference. And here's the catch: a badly planned extension doesn't just fail to bring in light. It can actually darken your existing rooms. We've all seen those extensions where the original kitchen ends up as a dingy corridor to reach the bright new bit at the back.

Which way your extension faces matters enormously. South-facing rear extensions can have generous glazing. You'll get lovely passive solar gain in winter. But you also need to think about summer overheating. North light is cooler and more consistent, though you'll want to maximise the glazing to capture what you can. East-facing? Morning sun flooding the breakfast table. West-facing? Perfect for evening entertaining as the sun sets into your extension.

Roof lights are your secret weapon, especially for deeper extensions. Skylights, lanterns, long strips of glass running the length of the ceiling: they all bring daylight from above, which is particularly useful when neighbouring houses limit your options for side windows. But don't just plonk them anywhere. Think about where that light will fall at breakfast time, at dinner, on a winter afternoon. Position matters.

Large-format sliding or bi-fold door systems create powerful visual and physical connections to gardens, effectively extending living space outward in warmer months. However, balance is essential. Entirely glazed elevations can feel exposed and present thermal challenges. Consider the ratio of solid to void, using opaque sections to provide privacy, anchor furniture placement, or house services.

Side extensions face particular daylighting challenges. Neighbouring properties often severely constrain fenestration opportunities, making roof lights essential. Clerestory windows (high-level glazing above eye level) maintain privacy whilst flooding interiors with light. Alternatively, narrow vertical windows or carefully positioned openings can frame specific views or admit controlled light without compromising privacy.

For comprehensive guidance on daylighting standards in residential design, the Royal Institute of British Architects (RIBA) provides detailed resources that inform best practice approaches to natural light in extensions.

For more detailed guidance on optimising natural light in your extension, see our article on daylighting strategies for modern home extensions, or discover how to choose the right glazing solutions for connecting inside and outside spaces.

Integrated Storage Solutions

Extensions provide opportunities to fundamentally rethink storage throughout your home. Built-in solutionsprove far more space-efficient than freestanding furniture, and designing storage from the outset ensures it integrates harmoniously with your aesthetic vision rather than being awkwardly retrofitted later.

Consider storage holistically across your extended ground floor. Kitchen extensions might incorporate full-height larder cupboards, appliance garages, or walk-in pantries. These are particularly valuable if the extension allows you to relocate utility functions. Window seats with lift-up lids combine comfortable seating with concealed storage, particularly effective along garden-facing elevations.

Bespoke joinery, though requiring greater investment than off-the-shelf alternatives, maximises every centimetre. Floor-to-ceiling bookcases, media units that conceal technology when not in use, or banquette seating with integrated storage all enhance functionality without visual clutter. Think about different storage types: some items require easy access, others can occupy less accessible locations like high cupboards or deep underfloor spaces.

Don't overlook opportunities to improve circulation-related storage. Enlarged hallways or through-spaces might accommodate coat storage, shoe cupboards, or bike stores, particularly relevant if your extension creates a more practical garden access point.

Planning Permission and Permitted Development Rights

Good news first: many single storey extensions qualify as permitted development. That means no planning application needed, though there are size limits and conditions to meet. The Planning Portal is your friend here. It'll tell you whether your plans qualify, though be warned: the rules can vary depending on your property type and where you live.

Here's the basic maths: detached houses can go four metres back from the original rear wall. Semi-detached and terraced properties get three metres. But (and this is important) these rights don't apply everywhere. Conservation areas? Forget it. National Parks or AONBs? Additional restrictions apply. Article 4 directions? That's when your local council has specifically removed permitted development rights in certain areas. And if you've got a listed building, you'll need both planning permission and listed building consent. Historic Englandhas the guidance on that.

Height limits matter too. Four metres maximum for the extension, three metres for the eaves. Side extensions have their own specific rules about width and roof form. These numbers might seem arbitrary, but they'll shape what your architect can do, so it's worth getting advice early.

Even where permitted development rights exist, larger single storey rear extensions may require prior approval through a process called the 'larger home extension' scheme. This involves notifying adjoining neighbours, who have 21 days to comment. Local planning authorities then have 42 days to assess impacts on neighbouring amenity.

Front and side extensions face more stringent planning controls. Front extensions rarely benefit from permitted development rights, typically requiring full planning applications. This reflects greater sensitivity around streetscape character and public realm impacts.

The UK Government Planning Portal provides detailed permitted development guidance worth reviewing early in your planning process. These regulations may seem complex, but understanding them helps architects design solutions that work within the framework.

Navigating the planning system can feel complex. Our comprehensive guide on securing planning permission for extensions explains the process step-by-step, whilst our article on permitted development vs planning permission clarifies which route applies to your project.

Building Regulations Compliance

Regardless of planning status, all extensions must comply with Building Regulations. These comprehensive technical standards ensure structural safety, fire protection, energy efficiency, accessibility, and proper drainage. Building Control approval involves submitting detailed technical drawings and calculations, followed by inspections at key construction stages.

Part L (Conservation of Fuel and Power) mandates minimum thermal performance standards for extension walls, roofs, floors, and glazing. This influences material choices, construction methodologies, and detailing approaches. The Energy Saving Trust provides helpful guidance on improving home energy efficiency through extensions. Extensions must also meet requirements for ventilation, sound insulation where applicable, and structural integrity.

The Party Wall Act 1996 may apply if your extension abuts or affects boundaries with neighbouring properties. This statutory framework requires formal notification and, potentially, agreements before work commences. The Royal Institution of Chartered Surveyors (RICS) provides guidance on party wall procedures, and party wall surveyors ensure works don't adversely affect neighbouring structures.

Your architect or structural engineer will coordinate Building Control submissions, ensuring technical compliance whilst achieving your design aspirations. The Institution of Structural Engineers (IStructE) sets professional standards for structural design. Building Control Officers make site visits at foundations, damp-proof course, structural frame, and pre-completion stages, issuing a completion certificate once satisfied with compliance.

To understand more about technical requirements, read our detailed explanation of Building Regulations for home extensions, or learn about what to expect during the Building Control process.

2. Double Storey Extensions: Rear and Side

Double storey extensions represent a substantial architectural intervention, delivering maximum spatial gain by building vertically. By extending across two floors, you effectively double your return on the ground footprint, creating significant additional accommodation whilst preserving more garden or external space than equivalent single-storey alternatives.

These extensions suit families requiring substantial additional space. Perhaps a new master bedroom suite with ensuite bathroom above an expanded kitchen-dining area, or a home office above a garden room. The investment is considerable, but the spatial transformation can be dramatic, fundamentally reimagining how your home functions across both levels.

Internal Spatial Dynamics and Planning

Two-storey extensions demand comprehensive spatial planning across both floors simultaneously. Unlike single-storey additions where you can focus exclusively on ground-floor arrangements, multi-level extensions require coordination between upper and lower floors, ensuring structural elements align vertically, service routes connect logically, and room layouts make sense independently whilst functioning as a cohesive whole.

Ground floors typically accommodate expanded living spaces: kitchen-dining extensions being most common, though some projects create additional reception rooms, utility areas, or home offices. First floors most frequently deliver bedroom accommodation, often with ensuite facilities, though home offices, playrooms, or hobby spaces feature increasingly in response to changing working patterns.

Critical to success is maintaining appropriate room hierarchies. Primary bedrooms above reception spaces work logically; bedrooms above kitchens require careful acoustic design. Consider ceiling heights too. Regulations mandate minimum dimensions, but generous proportions transform lived experience. Coordinating floor levels between existing and new structures presents particular challenges; even minor level differences create accessibility issues and disrupt flow.

The extension provides opportunities to rationalise your entire floor plan. Perhaps awkward upstairs circulation can be improved, or that problematic bathroom repositioned. Think strategically about how the extension enables improvements throughout your home, not just within the new footprint.

Flow and Vertical Circulation

Vertical circulation (how you move between ground and first floors) becomes paramount in two-storey extensions. Most extensions connect to existing staircases, meaning upper-floor access remains unchanged. However, if the extension allows you to reconfigure stair positions or add secondary staircases, circulation patterns can be fundamentally reimagined.

Consider landing spaces carefully. Cramped landings create bottlenecks and feel mean-spirited; generous landings accommodate multiple people, can house built-in storage, and make homes feel more spacious. Sightlines matter too, being able to see from landing into new first-floor rooms creates visual connections that enhance the sense of openness.

Ground-floor flow requires equal attention. Two-storey extensions often enable removal of more internal walls than single-storey alternatives because structural loads distribute differently. This creates opportunities for expansive open-plan arrangements. However, completely open spaces can feel undefined; use level changes, joinery elements, or material transitions to subtly zone areas whilst maintaining visual connectivity.

First-floor circulation patterns influence daily life substantially. Avoid creating long corridors serving multiple rooms; they waste space and feel institutional. Instead, consider how rooms relate to landings, whether ensuites reduce bathroom queues, and how privacy is maintained between bedrooms.

Daylighting Strategies Across Two Levels

Achieving adequate daylight across two storeys requires coordinated glazing strategies that respond to each floor's distinct requirements. Ground floors typically prioritise visual connection to gardens and outdoor spaces, whilst first floors balance daylight needs against privacy considerations.

Ground-floor glazing in two-storey extensions often mirrors single-storey approaches: large sliding or bi-fold systems opening to gardens, supplemented by roof lights where depth prevents adequate side fenestration. However, the floor above influences design options; loadings from first-floor structures can limit glazing widths unless substantial structural beams support upper walls.

First-floor fenestration requires careful calibration. Bedroom windows need adequate daylight without compromising privacy, particularly relevant where extensions extend closer to boundaries than original houses. High-level windows admit light whilst maintaining privacy; carefully positioned standard windows frame sky views rather than neighbouring properties. Bathroom and ensuite lighting often relies on roof lights, providing excellent natural light whilst ensuring privacy.

Roof lights prove invaluable in two-storey extensions, bringing daylight deep into both floors. Positioning requires thought; first-floor roof lights directly illuminate upper rooms, whilst double-height spaces with high-level roof glazing can flood ground floors with overhead light, creating dramatic spatial effects.

Consider seasonal and diurnal light variation. South-facing first-floor rooms can overheat in summer; appropriate shading, ventilation, or external blinds maintain comfort. North-facing rooms require maximised glazing to capture available light. Modelling daylight digitally helps predict actual conditions before committing to glazing configurations.

Integrated Storage Across Two Levels

Two-storey extensions facilitate comprehensive storage planning across both floors, addressing requirements that vary fundamentally between ground and first-floor functions. Strategic distribution of storage types (some easily accessed, others for less-frequent requirements) maximises usability whilst maintaining clear, uncluttered living spaces.

Ground floors typically accommodate frequently accessed storage: kitchen pantries, utility cupboards, coat storage near entrances, or media equipment housing in living areas. These benefit from generous proportions and thoughtful organisation: pull-out drawers, adjustable shelving, and dedicated spaces for specific items all enhance daily functionality.

First-floor storage serves different needs: wardrobes and drawer units in bedrooms, linen cupboards on landings, or airing cupboards integrating boiler systems. Two-storey extensions often create opportunities for walk-in wardrobes or dressing rooms: particularly if the extension delivers a new master bedroom suite. These require minimum dimensions to function properly; cramped walk-ins prove less effective than well-designed fitted wardrobes.

Utilising structural depths intelligently creates additional storage. The space beneath staircases, eaves storage in rooms with sloping ceilings, or Boxing-in services can all incorporate concealed cupboards. Coordinate storage planning with structural and services design from the outset to maximise every available centimetre.

Storage planning significantly impacts how well your extension functions daily. Discover clever storage solutions for home extensions or explore the benefits of bespoke joinery in maximising space.

Planning Permission for Two-Storey Extensions

Two-storey extensions rarely qualify as permitted development, typically requiring formal planning applications. Local planning authorities scrutinise these proposals carefully, assessing impacts on neighbouring properties, visual prominence within streetscapes, and appropriateness relative to the original building's character.

Key planning considerations include overshadowing (whether the extension will reduce daylight to neighbouring windows or gardens) and overlooking, particularly from new first-floor windows towards neighbouring private spaces. Planning officers apply well-established principles around acceptable separation distances, typically requiring minimum spacings to maintain privacy.

Design quality matters substantially in planning decisions. Extensions should respect the original building's proportions, use sympathetic materials, and typically remain subordinate to the main house. The Design Council champions excellence in built environment design. Matching brick bonds, slate types, or window patterns helps extensions sit comfortably with existing structures. Conversely, contemporary interventions can succeed where they clearly read as modern additions whilst respecting overall composition and scale.

Your architect will prepare comprehensive planning drawings including elevations, floor plans, and site sections demonstrating relationships with neighbouring properties. Design and Access Statements articulate design intentions and demonstrate how proposals respond to site context and planning policies.

Successfully navigating the planning process for substantial extensions requires expertise and preparation. Learn our tips and strategies for securing planning permission, or understand how design quality influences planning decisions.

Building Regulations for Multi-Storey Construction

Two-storey extensions face heightened Building Regulations scrutiny compared to single-storey additions. Structural requirements intensify; foundations must support increased loads, wall thicknesses require careful specification, and floor structures need comprehensive engineering to ensure stability and adequate sound insulation. The National House Building Council (NHBC) provides technical guidance and standards that inform best practice in residential construction.

Fire safety provisions become more stringent with multiple storeys. First-floor rooms require protected escape routes, typically meaning fire doors, adequate corridor widths, and appropriate fire resistance between floors. If the extension creates three-storey accommodation, additional requirements apply, potentially including sprinkler systems depending on specific circumstances.

Acoustic performance between floors demands careful attention. Building Regulations specify minimum sound insulation standards to prevent noise transfer: critical for maintaining privacy and comfort. This affects floor construction details, potentially requiring resilient layers, increased mass, or acoustic treatment that impacts ceiling heights and construction depths.

Thermal performance, ventilation, drainage, and accessibility requirements mirror those for single-storey extensions, though coordinating services across two floors adds complexity. Your design team will integrate all these technical requirements whilst achieving your architectural vision, ensuring comprehensive compliance without compromising design quality.

3. Single Storey Garden Extensions and Garden Rooms

Garden rooms and detached garden extensions represent a distinctive extension typology. Structures positioned away from the main house, creating self-contained spaces within your garden. These pavilion-like buildings offer remarkable flexibility, serving as home offices, studios, guest accommodation, or leisure spaces whilst maintaining physical separation from the main dwelling.

The appeal lies partly in minimal disruption to the main house during construction, and partly in the distinct character these buildings possess. A garden room separated from your house by even a few metres creates psychological distance. This transforms how you use the space. Home offices feel genuinely separate from domestic life; studios benefit from focused, undistracted environments; guest rooms provide privacy for visitors and hosts alike.

Layout and Positioning Strategy

Positioning garden extensions requires careful analysis of your plot's characteristics: orientation, existing landscaping, boundary relationships, and views. Unlike attached extensions where position is largely predetermined, garden rooms offer considerable freedom in placement, making strategic siting decisions critical to success.

Solar orientation fundamentally influences comfort and energy performance. South-facing garden rooms maximise passive solar gain and daylight, ideal for year-round studios or home offices. North-facing positions suit uses requiring consistent, diffused light. Artist studios traditionally favour northern light for its quality. East-facing rooms capture morning sun; west-facing positions enjoy afternoon and evening light.

Consider relationships with existing buildings and landscaping. Garden rooms can terminate vistas, frame particular views, or create courtyards between themselves and the main house. Think about how you'll move between house and garden room, across open lawn, along paths, or through planted areas? This journey affects usability significantly, particularly in poor weather.

Boundary relationships matter too. Garden rooms positioned near boundaries require careful consideration of neighbouring impacts: privacy, overshadowing, and overlooking all apply even though structures are detached from the main house. Positioning buildings away from boundaries often proves beneficial, creating buffer zones and reducing planning sensitivities.

Internal layouts for garden rooms typically favour simple, efficient plans. Single large spaces suit most uses: studios, offices, or occasional guest rooms, though some schemes incorporate small utility zones or shower rooms. Avoid over-compartmentalising modest footprints; clear, uncluttered spaces function better and feel more generous.

Scale and Proportional Relationships

Getting scale right proves critical with garden rooms: too small and they feel cramped and mean; too large and they dominate gardens and potentially create planning difficulties. The building must relate comfortably to both your garden's size and the main house's scale, creating harmonious relationships rather than awkward juxtapositions.

Garden rooms generally work best when they read clearly as subsidiary structures: smaller than the main house, with simpler forms and lower ridge heights. This maintains hierarchical clarity within your plot. However, contemporary garden rooms often employ architectural distinctiveness, modern pavilions alongside traditional houses can work beautifully when proportions and materiality are considered carefully.

Height matters significantly. Lower, more horizontal garden rooms sit comfortably in most gardens, reducing visual impact and often benefiting from permitted development allowances. Permitted development typically allows garden buildings up to four metres high for dual-pitched roofs, or three metres for other roof types, provided they're positioned specific distances from boundaries.

Consider proportion within the building itself, room dimensions, window sizes, door heights all contribute to architectural quality. Generous ceiling heights create spaciousness even in modest footprints; carefully proportioned windows frame views whilst maintaining appropriate solid-to-void ratios in elevations.

Maximising Natural Light

Garden rooms offer exceptional opportunities for natural light. being detached structures, they can be glazed on multiple sides without neighbouring properties constraining fenestration. This creates potential for beautifully light-filled spaces, though balance remains essential to avoid overheating, glare, or excessive heat loss.

Consider glazing strategically according to function and orientation. Home offices benefit from generous glazing on multiple elevations, creating bright, pleasant working environments. However, avoid positioning desks directly against south-facing glass where solar gain creates glare on screens; instead, consider north or east-facing working positions with south-facing glazing behind or to the side.

Studios, whether for art, music, or other creative pursuits. have specific lighting requirements. Artists often prefer consistent northern light; photographers might want controllable lighting; yoga or pilates studios benefit from uplifting, changeable light that connects to the surrounding garden. Tailor glazing configurations to intended use.

Roof lights work particularly well in garden rooms, admitting overhead daylight that floods spaces evenly. Contemporary flat-roof garden rooms often incorporate large-format flat roof lights or linear glazing that creates dramatic lighting effects. Traditional pitched-roof garden rooms might feature conservation-style roof lanterns that add architectural character whilst admitting generous daylight.

Glazing quality affects both thermal performance and aesthetic. Slim-framed systems maximise glass area and create refined elevations; thermally broken aluminium or high-performance timber systems deliver excellent insulation without compromising appearance. Consider maintenance too. easy-clean glass coatings prove worthwhile for roof lights.

Storage Considerations

Storage requirements in garden rooms vary dramatically according to function. Home offices need filing systems, stationery storage, and potentially server or IT equipment housing. Art studios require materials storage, often with considerable space devoted to canvases, paints, or sculptural elements. Guest rooms need wardrobe space and luggage storage. Gyms require equipment storage when not in use.

Built-in solutions prove more space-efficient than freestanding furniture, particularly relevant in garden rooms where footprints are often modest. Floor-to-ceiling joinery along one or two walls can house substantial storage whilst maintaining clear floor areas. Concealed storage behind joinery panels maintains clean aesthetic whilst providing functional capacity.

Consider whether storage should be visible or concealed. Creative studios might display materials and tools. open shelving creating visual interest and maintaining accessibility. Offices might require mixed storage. some items concealed behind doors, others on open shelving. Guest rooms benefit primarily from concealed storage to maintain uncluttered, restful environments.

Don't overlook outdoor storage associated with garden rooms. Tool storage, garden furniture, or equipment related to the garden room's function might require dedicated external sheds or stores positioned discreetly nearby.

Planning Permission for Garden Buildings

Many garden rooms qualify as permitted development under 'outbuilding' regulations, allowing construction without planning permission subject to specific limitations. These rules are more generous than those for attached extensions but still impose meaningful constraints that influence design options.

Permitted development allows garden buildings covering up to 50% of your garden area (excluding the original house footprint), though practical considerations usually result in far smaller buildings. Height restrictions apply: four metres maximum for pitched roofs, three metres for other roof types, reducing to 2.5 metres if within two metres of boundaries.

Buildings positioned forward of your principal elevation (typically the front) rarely qualify as permitted development. Certain uses may also trigger planning requirements: garden buildings used as primary residential accommodation or for business purposes often require permission regardless of size. The distinction between 'incidental' use (permitted) and primary accommodation (requiring permission) can be nuanced; your architect can advise on specific circumstances.

As with all permitted development, gardens in conservation areas, AONBs, National Parks, or sites of special scientific interest face additional restrictions. Article 4 directions may remove permitted development rights entirely. Listed building curtilages present particular complexities. garden buildings within the curtilage of listed buildings often require listed building consent regardless of permitted development status.

Understanding the regulatory framework for garden buildings ensures your project proceeds smoothly. Read our guide on garden room design, planning and permissions, or explore permitted development rights for garden buildings.

Building Regulations for Detached Garden Structures

Building Regulations requirements for garden rooms depend significantly on size, use, and permanence. Small garden buildings (typically under 15 square metres internal floor area) positioned more than one metre from boundaries and containing no sleeping accommodation often exempt from most Building Regulations, requiring approval only for electrical work.

Larger garden rooms or those intended for sleeping require full Building Regulations compliance covering structure, thermal performance, fire safety, drainage, and electrical installations. This adds complexity and requires technical submissions, though doesn't fundamentally constrain design quality. many superb contemporary garden rooms meet all regulations whilst achieving exceptional architectural character.

If your garden room includes bathroom facilities or kitchens, drainage connections require Building Control approval regardless of building size. Foundations must be adequate for ground conditions; thermal performance must meet current standards if the building is habitable. Your architect will determine precise requirements based on your specific proposal.

4. Basement Extensions

Basements are brilliant, if you can afford them and if your site allows it. They're technically complex, no question. But think about it: you gain substantial space without losing any garden, without changing how your house looks from the street. In tightly constrained urban areas where every square metre of garden matters and where planning scrutinises every external alteration, going down rather than out or up makes a lot of sense.

Home cinemas love basements: natural sound insulation, easy light control. Wine cellars too, with their stable temperatures. We've done gyms, swimming pools, playrooms, home offices, even guest bedroom suites down there. The trick is making these underground rooms feel like genuine parts of your home rather than forgotten storage spaces. That means getting light down there, ensuring decent ventilation, and creating proper connections to the rest of your house.

Creating Effective Spatial Connections

The fundamental challenge with basement extensions lies in their underground position. they inherently lack direct garden connections and risk feeling disconnected from your home's main living spaces. Success depends on establishing strong visual, physical, and atmospheric connections that integrate basements into your home's spatial sequence rather than creating isolated, forgotten rooms.

Visual connections prove particularly important. Where possible, create sightlines from upper floors into basement spaces. perhaps through glazed doors at stair heads, or double-height voids that allow glimpses downward. Even partial visual connections make basements feel less remote. Consider materials and finishes too; continuing flooring materials, wall colours, or architectural details from ground floors down into basements creates coherence.

Successful basement rooms often benefit from some connection to external ground level. 'light wells' or sunken courtyards that bring daylight and fresh air below ground whilst creating visual links to gardens. These features transform basement experiences, admitting natural light and enabling direct ventilation whilst providing psychological connection to the outside world.

Think about acoustic relationships between basement and upper floors. Basements naturally offer sound isolation. excellent for music rooms, home cinemas, or noisy activities. but this isolation shouldn't feel oppressive. Consider whether you want to hear activity from upper floors or maintain complete acoustic separation, and design accordingly.

Staircase Design and Vertical Flow

Staircases to basements critically influence how integrated these spaces feel within your home. Poor staircase design makes basements feel remote and rarely used; excellent staircases create anticipation and welcome, encouraging regular use and maximising your investment.

Positioning matters enormously. Ideally, basement stairs descend from central circulation spaces. hallways or landings. making them natural extensions of your home's movement patterns. Avoid tucking stairs away in forgotten corners or behind multiple doors; such positioning psychologically separates basements from daily life.

Stair proportions affect comfort significantly. Building Regulations mandate minimum dimensions, but generous stairs with comfortable rises and going measurements, adequate headroom, and landings where direction changes make basement access pleasant rather than forbidding. Consider stair width too. narrow stairs feel constricted when carrying items; wider stairs suggest importance and encourage use.

Daylighting staircases enhances the descent experience remarkably. Roof lights above stairs, glazed doors at the top, or light wells visible during descent all make basement access feel lighter and more welcoming. Artificial lighting design matters equally. well-lit stairs with thoughtful lighting sequences create atmosphere and ensure safety.

Stair materiality and detailing contribute significantly to perceived quality. Handrails at comfortable heights, non-slip treads, and carefully detailed junctions with walls and floors all demonstrate attention to craft. Consider whether stairs should match existing stair detailing elsewhere in your house or establish distinct character appropriate to basement functions.

Daylighting Strategies for Below-Ground Spaces

Bringing natural light into basements represents the primary design challenge. addressing it successfully transforms basement extensions from dark, cave-like spaces into comfortable, habitable rooms that enhance rather than compromise your home. Multiple strategies exist, often used in combination to maximise daylight penetration.

Light wells. excavated areas outside basement windows. provide the most effective daylighting solution. These sunken courts allow basement windows to function normally, admitting direct daylight and enabling natural ventilation. Sizing light wells appropriately requires balancing daylight requirements against safety, maintenance access, and garden impact. Deeper light wells admit more light but consume more external space; shallower wells prove more space-efficient but limit daylight.

Positioning light wells strategically maximises their effectiveness. South-facing light wells capture more sun; east or west-facing wells provide morning or evening light; north-facing wells deliver consistent, diffused daylight. Consider what basement windows overlook too. light wells opening to gardens create pleasant outlook and psychological connection; those against blank walls feel more constrained.

Glass pavement lights or structural glass floors at ground level provide alternative daylighting approaches, allowing light to filter down through the ground floor into basements below. These work particularly well in hallways or circulation spaces where you're willing to have glazed floor sections. The visual effect of looking down through floors adds architectural interest whilst serving a functional purpose.

Internal voids. double-height spaces connecting ground and basement floors. create dramatic spatial relationships whilst channelling daylight downward. These suit larger projects where you can afford to sacrifice some ground-floor area for the spatial and lighting benefits of a void. Voids create remarkable sense of volume and transform how basements relate to upper floors.

Where natural daylighting proves impossible or impractical, excellent artificial lighting design becomes critical. Contemporary LED systems can create lighting qualities that approximate natural light reasonably effectively, though they never entirely replicate it. Consider layered lighting. ambient, task, and accent lighting. to create variety and interest in artificially lit basement rooms.

For detailed guidance on daylighting strategies in basement design, the Building Research Establishment (BRE) provides comprehensive technical resources that help architects maximise daylight in below-ground spaces through various proven strategies.

Planning Permission for Basement Extensions

Basement extensions rarely qualify as permitted development except in very limited circumstances. generally requiring formal planning applications. This reflects their potential impacts on structural stability, drainage, neighbouring properties, and, in some areas, concerns about cumulative basement development affecting groundwater and geological stability.

Some local authorities. particularly in London boroughs where basement development has been extensive. have adopted specific basement development policies. These may limit basement footprint relative to garden area, restrict depth, or require comprehensive structural and hydrological impact assessments. The Royal Town Planning Institute (RTPI) provides resources on planning policy development. Policies vary significantly between authorities; early consultation with planning officers proves essential.

Planning applications for basements typically require detailed supporting information: structural methodology statements explaining excavation and construction approaches; impact assessments demonstrating no harm to neighbouring properties; drainage strategies; and sometimes hydrological or geological reports if local geology presents particular challenges.

External alterations. light wells, external basement access doors, or ventilation grilles. all require planning consideration. Even though the basement itself sits underground, these external manifestations affect appearance and potentially impact neighbours, informing planning assessment.

Building Regulations and Structural Requirements

Basement construction demands rigorous Building Regulations compliance across multiple technical domains. Structural design requires particular scrutiny. excavating below existing buildings affects their support, necessitating temporary works during construction and permanent underpinning or similar structural interventions. Structural engineers specialising in basement construction should lead technical design.

Waterproofing proves critical. basements below water table require comprehensive tanking systems to prevent water ingress. British Standard BS 8102 provides guidance on basement waterproofing, specifying different 'grades' according to intended use. Habitable basements require Grade 3 (dry environment) protection; storage basements might accept Grade 2 (some dampness tolerable); car parking might use Grade 1 (water-resistant but dampness acceptable).

Fire safety regulations govern means of escape from basements, typically requiring protected routes and potentially sprinkler systems depending on depth and use. Ventilation requirements ensure adequate air quality. mechanical ventilation systems often prove necessary where natural ventilation proves insufficient. Drainage. both foul and surface water. requires comprehensive design to prevent flooding and ensure proper waste disposal.

Party Wall Act considerations apply whenever basement excavation affects neighbouring properties, common in terraced or semi-detached properties. Formal party wall agreements must be established before works commence, protecting both your interests and those of neighbours.

5. Swimming Pool Extensions

Swimming pool extensions represent a luxury addition that transforms how homeowners use their properties, creating dedicated wellness and leisure facilities within residential settings. Whether indoor pools attached to main houses, detached pool houses in gardens, or basement pool installations, these projects demand specialised architectural and engineering expertise addressing the unique environmental conditions pools create.

The architectural challenge extends beyond simply housing a body of water. Pool extensions must address high humidity environments, manage complex mechanical and electrical services, create appropriate spatial character for swimming and relaxation, integrate changing facilities and technical plant rooms, and often incorporate associated amenities like gyms, saunas, or entertaining spaces.

Strategic Positioning and Site Planning

Pool extension positioning significantly influences both functionality and planning prospects. Attached pool extensions connect directly to main houses: convenient for daily use and allowing shared services, but potentially impacting the original building's character and requiring careful architectural integration. Detached pool houses positioned in gardens offer design freedom and atmospheric distinction but necessitate outdoor circulation in all weathers.

Solar orientation affects pool environments considerably, particularly for pool buildings with significant glazing. South-facing pools maximise passive solar gain. valuable for reducing heating demands and creating bright, sunny swimming environments. However, excessive glazing on south elevations can cause overheating and glare; balance proves essential. East or west orientations provide morning or afternoon sun respectively; north-facing pools require entirely artificial climate control but avoid solar gain complications.

Consider relationships with existing buildings and landscape features. Pool houses positioned to create courtyards with main dwellings establish protected, private swimming environments. particularly valuable in urban settings. Views from pool buildings matter too; overlooking gardens creates pleasant outlook whilst swimming, though privacy from neighbouring properties requires careful consideration.

Ground conditions significantly influence positioning decisions. Pool structures impose substantial loads and require robust foundations; poor ground conditions necessitate expensive foundation solutions. Proximity to existing drainage, electrical supplies, and water mains affects installation costs and complexity. Existing trees present particular challenges. root protection zones may constrain building positions, and tree roots can damage pool structures over time if positioned too close.

Basement pool installations offer intriguing alternatives. consuming no garden space and integrating discreetly within properties. However, excavation complexity, waterproofing requirements, and daylighting challenges make basement pools amongst the most technically demanding residential projects.

Natural Light in Pool Environments

Daylighting swimming pool enclosures requires balancing multiple considerations. desire for bright, uplifting environments against privacy needs, thermal performance requirements, and managing solar gain to prevent overheating. The unique combination of high humidity, temperature, and light creates distinct atmospheric qualities that influence design approaches.

Large-format glazing systems create spectacular pool environments, establishing strong visual connections to gardens and flooding spaces with natural light. Contemporary pool buildings often feature full-height glazing on garden-facing elevations, creating pavilion-like transparency. However, such extensive glazing demands high-performance glass specifications to manage heat loss, solar control, and condensation risks inherent to pool environments. The Glass and Glazing Federation (GGF) provides guidance on glazing standards and specifications for demanding environments.

Roof glazing proves particularly effective in pool buildings, admitting overhead daylight that creates even illumination across water surfaces whilst reducing reliance on vertical glazing where privacy concerns exist. Structural glass roofs, large-format roof lights, or traditional lantern designs all work well, though all require specification for high-humidity environments and regular maintenance access for cleaning.

Privacy represents a significant consideration in pool building daylighting. While you want natural light, overlooking from neighbouring properties proves problematic. High-level windows, clerestory glazing, or strategic positioning of solid walls and translucent glazing sections all balance daylight and privacy. Landscaping. carefully positioned trees or screening. can provide additional privacy whilst maintaining garden connections.

Consider how light interacts with water. Dappled light patterns reflecting off water surfaces create beautiful, ever-changing effects on walls and ceilings. Positioning windows or roof lights to maximise these effects adds considerable atmospheric quality to pool spaces. Underwater lighting deserves equal attention. well-designed pool lighting transforms evening swimming and creates dramatic visual effects when viewed from houses or gardens.

Storage and Support Spaces

Swimming pool extensions require substantial storage and support spaces beyond the pool hall itself. Pool plant rooms house filtration systems, heating equipment, chemical dosing apparatus, and control systems, typically requiring dedicated rooms with external access for maintenance and separate environmental controls from pool halls. These spaces, though utilitarian, must be appropriately sized and ventilated to ensure equipment operates effectively and safely.

Changing facilities require integrated storage solutions. cubicles or alcoves for clothing, towel storage (often heated to provide warm, dry towels), and potentially shower facilities. Consider whether pool users will change in main houses and walk to pools (requiring covered routes) or whether self-contained changing facilities within pool buildings prove more practical.

Pool equipment storage. floats, lane markers, cleaning equipment, pool toys. requires dedicated space, ideally adjacent to pool halls for convenient access. Built-in cupboards or separate store rooms keep these items organised and out of sight when not required. Pool chemicals demand particular attention. they must be stored securely, away from pool areas, in well-ventilated spaces meeting health and safety requirements.

Many pool extensions incorporate additional amenity spaces. gyms, saunas, steam rooms, or entertaining areas. Each function demands specific storage: gyms require equipment storage and potentially changing facilities; saunas need towel storage and potentially shower access; entertaining spaces benefit from bar areas, glassware storage, and integrated seating with concealed storage.

Swimming pool extensions represent significant architectural undertakings requiring specialist expertise. Explore our insights on designing spa and pool facilities for the home, or view our pool house architecture portfolio to see how we create luxury leisure spaces.

Planning Permission for Pool Buildings

Swimming pool extensions rarely qualify as permitted development, typically requiring formal planning applications. This reflects their substantial size, potential impacts on neighbouring amenity through noise and activity, and often significant architectural presence within plots. Planning authorities assess proposals carefully, considering visual impact, neighbour privacy, noise potential, and appropriateness relative to local context.

Design quality matters considerably in planning assessments. Pool buildings should relate comfortably to main houses in terms of scale, architectural language, and materials. Contemporary pool houses can successfully contrast with traditional main dwellings where design quality justifies the approach, but poorly considered schemes face planning refusal.

Noise represents a key planning consideration. Swimming, filtration plant, and social activity around pools generate noise that might affect neighbours, particularly relevant in denser residential areas or where pool buildings sit close to boundaries. Acoustic reports may be required for planning applications, demonstrating noise levels remain acceptable. Design mitigation. positioning plant rooms away from neighbours, incorporating acoustic insulation, or limiting hours of use through planning conditions. addresses these concerns.

In green belt locations or other constrained designations, pool buildings face heightened scrutiny. Demonstrating the pool serves the existing dwelling rather than creating separate residential accommodation becomes important. planning authorities sometimes express concern about pool houses being converted to independent dwellings, potentially leading to restrictive conditions preventing such conversion.

Building Regulations and Technical Requirements

Swimming pool extensions demand comprehensive Building Regulations compliance covering numerous technical domains. Structural design must address substantial water loads, humidity-induced corrosion risks to structural elements, and ground conditions. Pool structures themselves require specialised engineering. concrete pool shells or liner systems, each with specific structural requirements.

Moisture control proves critical. High humidity in pool halls risks condensation on cold surfaces, potentially damaging building fabric and creating unhealthy conditions. Building Regulations require appropriate vapour control layers, insulation strategies, and mechanical ventilation systems that manage humidity effectively. Windows and roof lights must be specified for high-humidity environments to prevent condensation and maintain visibility.

Electrical installations require particular care. Pools create potentially hazardous environments where water and electricity interact; Regulations mandate specific protection zones around pools with appropriate electrical safety measures. Only qualified electricians experienced in pool installations should undertake this specialist work.

Drainage systems must handle pool water discharge (both emergency overflow and routine water changes), surface water from pool surrounds, and standard foul drainage from changing facilities. Water treatment systems, filtration, and chemical dosing all require regulatory compliance and often necessitate Environment Agency consultation regarding water discharge.

Energy efficiency regulations apply to pool heating and environmental control systems. While pools inherently consume significant energy, specification of efficient plant, appropriate insulation, and potentially renewable energy integration can substantially reduce running demands. The Microgeneration Certification Scheme (MCS) certifies renewable energy installers for technologies like solar thermal for pool heating or photovoltaics for electrical loads.

6. Loft Extensions and Conversions

Look up. There's probably usable space up there that's currently just storing Christmas decorations and forgotten furniture. Loft conversions make perfect sense when you can't extend outwards (small garden) or downwards (geology or budget rules out basements). You gain proper rooms without touching your footprint, crucial in dense urban areas where every metre of garden counts.

'Conversion' versus 'extension'. what's the difference? A conversion works within your existing roof envelope. You're insulating, adding windows, putting in a proper floor and staircase, but the roof itself stays put. An extension involves changing the roof. maybe building up a hipped end to create a gable wall, or adding dormers to gain headroom and floor area. Extensions give you more space but they're more involved structurally and usually need planning permission.

Creating Effective Connections and Access

Staircase design critically influences loft extension success. Adding entirely new staircases to access loft levels affects ground and first-floor layouts significantly. staircases consume substantial floor area and require careful positioning to avoid compromising existing room layouts or circulation patterns. The challenge lies in finding positions that feel natural rather than forced, integrating staircases into your home's movement patterns rather than creating awkward diversions.

Building Regulations mandate minimum stair dimensions, headroom clearances, and landing sizes for habitable loft spaces. Staircases must be permanent, properly constructed stairs. retractable loft ladders don't satisfy regulations for habitable rooms. Space-saving stair designs. alternating tread stairs or spiral stairs. can work in constrained situations, though they're less comfortable for frequent use and may not suit all households, particularly those with young children or mobility considerations.

Consider where staircases land on first floors. Ideally, they should emerge from existing landing areas rather than requiring corridors through bedrooms or sacrificing bedroom area. Sometimes extending first-floor landings proves necessary to accommodate loft stairs properly. this affects first-floor room sizes and requires careful design to avoid creating awkward residual spaces.

Visual connections between loft levels and lower floors enhance integration. Glazed panels in stairwell walls, carefully positioned openings allowing glimpses between levels, or continuing material palettes upward all help loft rooms feel like natural parts of your home rather than separate, tacked-on spaces.

Think about access frequency when planning stair positions. Loft rooms used daily. home offices or principal bedrooms. benefit from convenient stair locations; guest rooms used occasionally tolerate less convenient access. Consider carrying furniture and equipment upstairs too; tight spiral stairs may save space but create practical challenges moving beds or office furniture to loft levels.

Spatial Flow and Room Configuration

Loft spaces present unique spatial qualities. sloping ceilings, varying head heights, and often irregular floor plans shaped by roof geometry. Successfully converting these characteristics from constraints into architectural opportunities defines excellent loft extension design. Understanding how people move through and occupy these distinctive spaces informs layout decisions.

Ceiling height variation creates natural zoning within loft rooms. Higher central areas suit primary activities: sleeping zones in bedrooms, desk positions in offices, seating areas in living spaces. Lower eaves areas, while too constrained for standing, work excellently for storage, reading nooks, window seats, or children's play areas. Embrace rather than fight these dimensional constraints; they create character and spatial variety impossible in conventional rectangular rooms.

Where loft extensions create multiple rooms. perhaps two bedrooms and a bathroom. circulation between rooms requires attention. Loft-level landing areas need adequate size to avoid cramped corridors; Building Regulations specify minimum dimensions. Consider whether ensuite bathrooms reduce landing bathroom demand, potentially allowing more compact circulation spaces. Privacy between loft rooms matters too. sound insulation between bedrooms requires appropriate wall construction and door detailing.

Some loft conversions create entirely open spaces rather than divided rooms. loft studios, playrooms, or home gyms often work better as single volumes that maximise sense of space. Here, the sloping ceiling geometry creates natural spatial definition without requiring partition walls that might feel cramped in modestly sized lofts.

Maximising Natural Light in Roof Spaces

Daylighting loft extensions differs fundamentally from ground or first-floor spaces. roof geometry enables overhead glazing that floods spaces with daylight, creating bright, uplifting environments despite being topmost floors. The challenge lies in balancing generous daylighting against thermal performance, privacy, and avoiding excessive solar gain or glare.

Roof lights provide the most effective loft daylighting strategy. Conservation-style roof windows, flat roof lights on contemporary flat-roof extensions, or glazed gable ends on A-frame conversions all admit substantial natural light. Positioning roof lights carefully maximises effectiveness. consider where light falls at different times of day and how it illuminates key activity zones.

Dormer windows. projections from roof slopes that create vertical window walls. combine daylighting with increased headroom and usable floor area. Rear dormers often qualify for permitted development (subject to size limitations), making them attractive options for cost-effective space gains. Front dormers face stricter planning controls but can dramatically improve street-facing loft rooms where roof lights alone prove insufficient.

Gable walls in loft spaces offer opportunities for full-height glazing, creating stunning light-filled spaces and often spectacular views across rooflines. Contemporary loft extensions sometimes feature entirely glazed gable ends, requiring high-performance glass to manage thermal performance but creating remarkable spatial experiences.

Solar control deserves careful attention in loft spaces. Roof glazing admits intense summer sun, potentially causing overheating despite excellent winter solar gains. Integrated blinds, external shutters, or high-performance solar control glass all mitigate overheating whilst maintaining daylight benefits. Ventilation. opening roof lights or dormer windows. proves essential for comfort in warm weather.

Privacy in loft spaces varies depending on position and surrounding context. Roof lights looking skyward rarely present privacy concerns; dormer windows overlooking gardens or streets require more careful consideration. High-level windows, translucent rather than transparent glazing, or strategic positioning relative to neighbouring properties all address privacy whilst maintaining daylight.

Selecting appropriate roof lights and dormers significantly affects loft conversion success. Learn about maximising daylight in loft conversions, or explore dormer design and architectural considerations.

Planning Permission and Permitted Development

Many loft conversions qualify as permitted development, though specific allowances depend on property type, location, and the extent of alterations. The most significant permitted development right allows rear dormers on houses, providing they don't exceed specified volume additions (40 cubic metres for terraced houses, 50 cubic metres for detached and semi-detached houses) and meet other criteria.

Permitted development rear dormers cannot extend beyond the existing roof plane on principal elevations (usually front-facing roofs), must sit at least 20cm from eaves, and must use materials similar to the existing house. These constraints mean front dormers typically require planning permission, though some modest roof lights on front slopes may qualify as permitted development.

Hip-to-gable conversions (where hipped roof ends are built up to create gable walls) affect external appearance significantly and usually require planning permission. These alterations change roof profiles noticeably, influencing streetscape character and neighbouring outlooks, making them appropriate subjects for planning assessment.

Properties in conservation areas, listed buildings, Article 4 direction areas, or other designated locations face restricted or removed permitted development rights for loft conversions. Here, even modest roof lights may require planning permission or listed building consent. Early consultation with local planning authorities clarifies requirements for specific properties.

The Planning Portal provides detailed guidance on loft conversion permitted development rules, helping you understand which alterations qualify and what restrictions apply to your specific property type and location.

Building Regulations for Loft Conversions

All loft conversions creating habitable accommodation require Building Regulations approval, covering structural alterations, fire safety, thermal performance, sound insulation, and staircase design. These requirements significantly influence design approaches and affect existing floors as well as new loft spaces.

Fire safety represents the most substantial regulatory consideration. Creating habitable loft rooms in two-storey houses transforms them into three-storey dwellings, triggering enhanced fire safety requirements. Typically, this means providing a protected stairway with fire-resistant construction and self-closing fire doors on all habitable rooms opening to stairs. First-floor room doors may require upgrading to fire doors. a significant alteration affecting the entire house, not just the loft.

Structural considerations involve both new loft floor structures and existing elements. New loft floors must support imposed loads appropriate to intended use (bedrooms, offices, or other functions have different loading requirements). Existing structures. particularly ceiling joists being converted to floor joists. may require strengthening. Removing structural elements like purlins or struts during conversion necessitates alternative structural support, often through steel beams or engineered timber frames.

Thermal performance regulations require loft conversions to meet current insulation standards. affecting roof construction thickness and potentially headroom. Achieving adequate insulation within limited rafter depths requires careful material selection; high-performance thin insulation systems cost more but preserve precious headroom. The Association for Environment Conscious Building (AECB) provides guidance on achieving excellent thermal performance. Ventilation requirements ensure adequate air quality in loft rooms, often necessitating background ventilation through trickle vents in windows plus mechanical extract in bathrooms.

Sound insulation between loft rooms and first-floor bedrooms below requires appropriate floor construction. typically including acoustic treatment layers. This adds to floor construction depth and affects headroom, requiring coordination between acoustic requirements and spatial needs.

Minimum ceiling heights apply in loft rooms: typically 2.3 metres over at least 50% of the floor area. The sloping nature of loft ceilings means careful planning ensures sufficient usable space whilst maximising floor area despite geometric constraints. Your architect will design floor layouts that optimise usable space within regulatory parameters

Realising Your Extension Vision

So there you have it. six different ways to extend your home, each with its own logic, its own challenges, and its own rewards. The right choice depends entirely on your circumstances: what you need, what your property can accommodate, what your budget allows, and frankly, what planning will let you do.

What ties all these approaches together? Light. Flow. How spaces connect. How they feel to actually live in, not just how they look on a plan. Get those fundamentals right, whether you're building a modest single storey extension or excavating an entire basement. and you'll end up with something that genuinely improves your daily life.

The planning and Building Regulations maze can feel daunting, we know. But it exists for good reasons, and once you understand the logic, it's navigable. That's where working with an experienced architect pays dividends. not just in getting approvals, but in designing something that works beautifully within (or occasionally, creatively around) the constraints.

At Alter, we've seen extensions transform homes and, genuinely, transform lives. More space, yes. But also more light, better connections to gardens, rooms that finally work the way they should. That's what good design delivers. If you're considering extending, invest the time upfront to get the design right. It's worth it.

Ready to begin your extension journey? Contact Alter Architects to discuss your project, book a consultationwith our team, or learn more about our extension design process.