extensions

House Extensions in Somerset and Beyond

Single-Storey and Two-Storey Rear Extensions

Rear extensions remain the most effective way to transform family homes, typically creating open-plan kitchen-dining spaces that connect with gardens. MJW Architects’ approach to rear extensions prioritises natural light penetration, spatial flow, and architectural integration with existing buildings.

The challenge with rear extensions lies in achieving adequate ceiling heights whilst complying with planning constraints on ridge heights and eaves levels. We employ various roof strategies—flat roofs with parapets, mono-pitched roofs, or dual-pitched forms—selected to maximise internal volume whilst respecting neighbouring amenity. Roof lights are positioned strategically to bring daylight deep into plans, avoiding dark zones where extensions meet existing buildings.

Two-storey rear extensions require careful compositional design to avoid overwhelming existing properties. We establish clear visual hierarchies through material changes, roof form variations, or deliberate setbacks that read as subordinate additions. Upper floor windows are positioned to achieve required natural light and outlook whilst minimising overlooking of neighbouring gardens—often the primary planning concern that determines application outcomes.

For kitchen extensions, we consider practical requirements beyond spatial planning: adequate task lighting for food preparation, ventilation strategies for cooking, and circulation patterns that allow multiple family members to occupy spaces simultaneously. Bi-fold doors or sliding glazing systems maximise opening widths, though fixed glazing often delivers better thermal performance and lower maintenance requirements.

Side Extensions and Wrap-Around Developments

Properties with available side access can benefit from side extensions, though planning constraints around boundary treatments and neighbouring impact make these projects particularly sensitive. Somerset planning authorities typically require minimum 1-metre separation from boundaries, with greater distances expected where side extensions include habitable room windows overlooking neighbouring properties.

Side extensions work effectively for utility rooms, home offices, or extending existing kitchens without impacting rear gardens. The architectural challenge involves integrating side additions with existing elevations—matching ridge heights, aligning window proportions, and selecting materials that unify extended buildings without appearing obviously added.

Wrap-around extensions combining side and rear additions deliver substantial floor area increases but demand skilled architectural design. These projects risk creating over-extended buildings with poor natural light penetration and awkward circulation routes. Success depends on establishing coherent spatial planning, ensuring adequate glazing to central areas, and designing external compositions that read as unified architectural forms rather than incremental additions.

Conservation Area and Listed Building Extensions

Extending properties within Conservation Areas or Listed Buildings requires specialist conservation knowledge and planning expertise. MJW Architects prepares detailed Heritage Statements that analyse architectural significance, assess impact of proposed extensions, and justify alterations through clear conservation rationale.

Conservation Area extensions face scrutiny regarding material selection, architectural detailing, and impact on area character. Some Conservation Areas favour matching materials and traditional forms that maintain historic character; others accept contemporary contrast where modern additions respect scale and massing whilst expressing their construction date honestly. We assess specific Conservation Area character and planning authority expectations to develop appropriate design approaches for individual projects.

Listed Building extensions must demonstrate minimal impact on significant fabric whilst creating viable additional accommodation. We employ reversible construction techniques—structural independence from historic walls, bolted fixings rather than mortared connections—that allow future removal without damaging original buildings. Modern extensions to Listed Buildings often work best when designed as clearly contemporary additions that respect historic architecture without attempting pastiche replication.

Planning applications for heritage extensions require comprehensive supporting evidence: historical research, photographic surveys, and detailed analysis of proposed interventions. Our heritage planning submissions demonstrate understanding of conservation principles and build confidence with conservation officers, improving consent prospects and reducing negotiation timescales.

Structural Considerations in Extension Projects

Extension design requires careful structural coordination from concept stage onwards. MJW Architects works with structural engineers to develop extension schemes that integrate with existing building structures whilst meeting Building Regulations requirements for structural stability and safety.

Common structural challenges include inadequate existing foundations requiring underpinning or alternative foundation strategies, masonry quality insufficient for new floor loadings, and roof structures requiring strengthening to accommodate extended spans. We address these through strategic structural interventions—steel beams concealed within floor depths, discrete reinforcement of existing walls, and new structural frames that support extension loads independently.

For large open-plan extensions, achieving clear spans without intermediate columns requires substantial structural members. We position these strategically: steel beams aligned with circulation routes, columns located where furniture layouts naturally create divisions, and structural grids that suit kitchen planning rather than compromise functional layouts.

Building Regulations compliance for extensions involves demonstrating adequate foundation design, structural calculations for all new elements, and appropriate fire separation between existing buildings and new construction. Our technical drawings communicate structural requirements clearly, ensuring contractors understand construction sequences and temporary support requirements during building works.

Thermal Performance and Building Regulations

Meeting Building Regulations thermal performance standards presents particular challenges when extending period properties with solid walls and single-glazed windows. New extensions must achieve U-values significantly better than existing buildings, creating thermal bridges where new construction meets old fabric.

We address thermal performance through high-specification insulation, thermally broken glazing systems, and careful detailing at junctions between new and existing construction. For Conservation Area and Listed Building projects where external insulation compromises architectural character, we maximise new extension insulation to compensate for existing building thermal limitations.

Glazing proportions significantly impact thermal performance—large glazed areas create heat loss in winter and solar gain in summer. We balance desire for garden connections against thermal efficiency, sometimes recommending reduced glazing areas or high-performance glazing specifications that improve U-values whilst maintaining design intent.

Building Regulations approval for extensions involves demonstrating compliance across multiple areas: structural safety, fire safety, thermal performance, ventilation, drainage, and electrical safety. MJW Architects coordinates these technical requirements, preparing comprehensive Building Regulations submissions that achieve approval without compromising design quality.

Planning Permission for House Extensions

Most house extensions require planning permission, though some qualify as permitted development under specific criteria. Permitted development rights vary based on property type, location, and previous extensions that may have exhausted available allowances.

Planning applications for extensions must address multiple considerations: impact on neighbouring amenity (particularly overlooking and loss of light), design quality and relationship to existing buildings, impact on Conservation Area character where relevant, and compliance with local plan policies. Our planning submissions anticipate these concerns, demonstrating how extension proposals respect neighbouring properties and enhance existing building character.

Somerset planning authorities expect high-quality design that contributes positively to local context. We prepare detailed Design and Access Statements that explain design rationale, material selection, and how proposals comply with planning policy requirements. Supporting this with clear drawings and realistic visualisations helps planning officers understand proposals and recommend approval.

For extensions in sensitive locations—Conservation Areas, Article 4 Direction areas, or sites adjacent to Listed Buildings—we provide additional heritage analysis demonstrating preservation or enhancement of special character. This evidence-based approach addresses conservation concerns proactively, reducing negotiation requirements and improving approval timescales.

Why Choose MJW Architects for Your Extension Project

MJW Architects brings over 25 years of RIBA chartered experience to house extension projects across Somerset, Bath, Bristol, and Frome. Our approach combines design quality with technical rigour, delivering extensions that enhance architectural character whilst meeting Building Regulations and planning requirements.

We understand local planning landscapes—Somerset’s Conservation Area policies, Bath’s World Heritage Site constraints, Bristol’s design quality expectations. This knowledge informs design development from concept stage, creating proposals that achieve planning approval efficiently whilst delivering spaces that genuinely improve how your home functions.

Our extension projects demonstrate how specialist architectural knowledge addresses complex challenges: integrating new construction with period buildings, maximising natural light within planning constraints, and creating spatial layouts that suit contemporary family living. The projects featured below show this approach across various scales, contexts, and architectural typologies.