Blog
Timings, rules and fees for kitchen extensions, one question at a time.
Do I need planning permission for a kitchen extension?
Usually not. In England a single-storey rear kitchen extension is permitted development if it reaches no more than 3 m beyond the original back wall of a terraced or semi-detached house, or 4 m on a detached house, and is no more than 4 m high. Flats, listed buildings, conservation areas and Scotland follow different rules, and building regulations approval is needed in every case.
How long does a kitchen extension take?
Allow 10 to 16 weeks of building for a single-storey kitchen extension. The part people underestimate is everything before the builder arrives: drawings, permission, building regulations and party wall notices usually add four to six months, so seven to ten months from first sketch to finished kitchen is a fair plan.
How much does an architect cost for an extension?
For a single-storey kitchen extension, planning drawings typically cost £1,000 to £2,500. A full service, from design through tender to inspecting the work on site, is usually charged at 3% to 15% of the build cost. The structural engineer, planning fee and building control are separate bills. These are typical national ranges for 2026, including VAT.
Kitchen extension ideas, and what each one does to the price
The ideas that improve a kitchen extension most are often the cheap ones: a rooflight where the old house meets the new, a window seat, a pantry wall. The expensive ones are nearly all glass. Decide early which of each you want, because the time to choose is before the drawings are priced.