Planning a house extension in Kent? Here's our honest, up-to-date guide to what you should expect to pay in 2026, based on real projects we've completed across the county.
Single-storey rear extensions remain the most popular option. For a standard 4m x 5m extension with bi-fold doors, expect to pay between £35,000 and £55,000 depending on specification. Larger extensions (up to 8m under permitted development) typically cost £50,000 to £75,000.
Two-storey extensions offer significantly better value per square metre. A typical two-storey rear extension costs between £55,000 and £90,000 — roughly 50% more than single-storey but delivering double the floor space.
Wrap-around extensions (combining side and rear) are increasingly popular for creating large open-plan kitchen-diners. These typically cost between £60,000 and £100,000+ depending on size and whether structural walls are involved.
Side return extensions in terraced and semi-detached homes are a cost-effective way to widen a narrow kitchen. Costs range from £25,000 to £45,000 for a typical side return infill.
Key factors affecting cost include: ground conditions and foundations, proximity to boundaries and party walls, level of finish (budget vs premium kitchen and bathroom fittings), structural steelwork requirements, and whether the project needs planning permission.
At TEMBOK, every extension quote is fixed-price with no hidden extras. We include foundations, structural work, roofing, electrics, plumbing, plastering and decoration as standard. What we quote is what you pay.