Blog
Planning limits, boundaries, roofs and tax: the things worth settling before a kit goes into production.
How close to my boundary can I build an extension?
You can build right up to the boundary, but each step closer brings a rule. Within 2 m the eaves must stay under 3 m for permitted development, within 1 m the wall must resist fire, and building on the line or digging near a neighbour's foundations means serving party wall notice.
How far can you extend without planning permission?
Behind an attached English house you can usually build out 3 m on one storey with no application, and 4 m behind a detached one. Prior approval from the council stretches that to 6 m and 8 m. Going up two storeys, the limit is 3 m and the extension must leave 7 m to the back boundary.
Is a lean-to extension kit right for your house?
A lean-to kit suits a house with enough wall height between the ground-floor ceiling and the sills of the upstairs windows. The roof needs a slope steep enough for the covering you choose, and the low edge has to clear the 3 m eaves limit near a boundary. Where the wall is too short, a flat roof kit is the better fit.
Do you pay VAT on an extension kit?
Yes. A kit for extending a house you already own attracts VAT at the standard 20%, and so does the building work. A homeowner cannot reclaim it. The main ways the bill can come in lower are trades too small to be VAT registered, and specific relief for adaptations for a disabled person.
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