Single-Storey Extension
Create a kitchen-diner, rear lounge, or open-plan family hub.
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Benefits of a Single-Storey Extension.
A single-storey extension is the most popular way to transform your home. Whether you need a larger kitchen, an open-plan family space, or a dedicated home office, extending at ground level gives you flexibility without the cost of building upward.
What's Included
Every single-storey extension project includes architect-led design and full technical documentation.
- Site survey and existing floor plans
- Design options exploring layout and orientation
- Planning application or lawful development certificate
- Structural engineer coordination
- Builder-ready construction drawings
Why work with us?
- Architect-led from day one
- Fixed fees, no surprises
- Planning success rate over 95%
- Direct communication throughout
Rear, Side, or Wraparound?
The best approach depends on your plot, lifestyle, and budget:
- Rear extension - Extends into your garden, ideal for kitchen-diners and living spaces with garden views.
- Side extension - Uses underutilised side access or garage space. Great for utility rooms, WCs, or widening existing rooms.
- Wraparound - Combines rear and side into an L-shaped extension. Maximises space but may require more planning consideration.
Permitted Development Limits
Under Permitted Development, you can typically extend:
- Detached homes - Up to 8m to the rear (or 4m under standard PD)
- Semi-detached/terraced - Up to 6m to the rear (or 3m under standard PD)
Extensions must not exceed 4m in height, cover more than 50% of the garden, or extend beyond the side wall facing a highway. We will confirm what is achievable for your property.
Design Considerations
A successful extension balances internal flow with external aesthetics:
- Natural light - Rooflights, bi-fold doors, and clerestory windows prevent the "dark middle" problem
- Connection to garden - Large glazed openings blur the boundary between inside and out
- Existing layout - Consider how the extension integrates with your current rooms
- Neighbours - Overlooking, overshadowing, and overbearing impact all affect planning success
Common Questions
How long does a single-storey extension take to build?
Typically 10-16 weeks for construction, depending on size and complexity. Allow 6-10 weeks beforehand for design, planning, and Building Regulations.
Do I need planning permission for a single-storey extension?
Many single-storey extensions fall under Permitted Development. However, if your home is in a Conservation Area, is a listed building, or you want to extend beyond PD limits, you will need planning permission.
How much does a single-storey extension cost?
Build costs typically range from £1,800-£2,500 per square metre, depending on specification. A 20m² extension might cost £40,000-£50,000 including finishes.
Will I need Building Regulations approval?
Yes. All extensions require Building Regulations approval covering structure, insulation, drainage, ventilation, and electrical safety.