House Extensions in Brighton & Hove
An extension is one of the biggest ways to add space and value to a home, but it is also one of the easiest to get wrong. In Brighton and Hove, the main challenges are tight sites, difficult access, older houses with unpredictable foundations, and getting new work to sit properly alongside period brickwork. A good extension is planned properly, built to the approved design, and tied into the existing house so it does not leak or crack later.
When This Service Is Needed
- You need more living space but do not want to move house.
- The kitchen is cramped and you want an open-plan kitchen-diner.
- A growing family needs an extra room, utility or downstairs WC.
- You want to open up the rear of the house onto the garden.
- The property has an awkward layout that an extension could resolve.
- You are extending as part of a wider renovation or refurbishment.
Brighton & Hove Property Context
Much of Brighton and Hove is made up of Victorian and Edwardian terraces on narrow plots, which affects what an extension can realistically achieve and how it gets built. Rear access is often limited, so materials and spoil may have to come through the house. Older foundations can be shallow and vary along a run of houses, so ground conditions need checking rather than assuming. Coastal weather also means the tie-in, roof falls and glazing all have to be weathered carefully. In flats and leasehold properties, extending is usually more complicated and may need freeholder consent, so the ownership position should be checked before any work is planned.
Construction & Materials
| Area | Recommended Approach |
|---|---|
| Foundations | Design based on ground conditions and Building Control input |
| Walls | Cavity construction with insulation to current standards |
| Flat or pitched roof | Correct falls, insulation and quality covering |
| Glazing | Double or triple glazed units, rooflights or bi-folds |
| Junction to existing house | Careful tying-in, flashing and weathering |
How We Approach the Work
- 01Discuss what you want to achieve and assess whether it is feasible.
- 02Check planning position, permitted development limits and any constraints.
- 03Coordinate design, structural calculations and Building Regulations drawings.
- 04Prepare the site, protect the existing house and set out the footprint.
- 05Dig and pour foundations to the approved design and inspection stages.
- 06Build the structure: walls, roof, openings and the tie-in to the house.
- 07First fix plumbing, electrics and heating, then insulate and plaster.
- 08Second fix, decorate, fit flooring and complete final testing and sign-off.
Common Mistakes
The biggest mistake is rushing into building before the design, planning position and structural details are properly settled. Starting on site with unresolved decisions leads to changes mid-build, which cost more and slow everything down. Foundations are another common problem, especially on older houses where the ground is not what was assumed and the design has to be revised on the spot.
The other frequent mistake is a poor junction between the new extension and the existing house. If the tie-in, flashing and roof weathering are not done carefully, this is exactly where leaks and cracking appear a year or two after the work looks finished.
Building Regulations
Extensions almost always require Building Regulations approval, covering foundations, structure, insulation, ventilation, drainage, fire safety and glazing. Where a wall between the house and the extension is removed to open up the space, that is structural work needing a structural engineer's calculations and usually a steel beam, signed off by Building Control. Electrical work must comply with Part P, and any drainage connections need to be handled correctly. Separately from Building Regulations, you may also need planning permission, or the work may fall under permitted development within set limits — those limits are tighter in conservation areas and for flats, so the planning position is always worth confirming before work starts.
Cost Factors
- Extension size and number of storeys.
- Ground conditions and foundation type.
- Complexity of the tie-in to the existing house.
- Amount of glazing, rooflights or bi-fold doors.
- Kitchen, bathroom or utility fit-out included in the work.
- Structural work such as steel beams where walls are removed.
- Access to the rear of the property for materials and waste.
- Level of finish and specification of fittings.
Frequently Asked Questions
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