Semi-detached rear extension in Ampthill

How much does a semi-detached rear extension cost in Ampthill?

In Ampthill, our guide for a semi-detached rear extension is £2,010–£3,290 per square metre including VAT for a standard specification. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.

Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.

Do you need planning permission for a semi-detached rear extension in Ampthill?

Here is how the rules in England apply to a semi-detached rear extension in Ampthill.

Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.

A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.

If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.

Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.

What are homes in Ampthill like to extend?

Post-war semis and newer estates are typical of Ampthill, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.

How a semi-detached rear extension in Ampthill comes together

1. Look round and measure

   A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.

2. Design and guide price

   Two or three layout options with a guide price for each, so you choose the design knowing what it costs.

3. Planning and regulations

   We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.

4. Build and sign-off

   We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.

Semi-detached rear extensions near Ampthill

We also build rear extensions for semi-detached houses in nearby Flitwick (1.6 miles) and Kempston Hardwick (4.3 miles).

• Semi-detached rear extension in Flitwick
• Semi-detached rear extension in Kempston Hardwick
• Semi-detached rear extension in Kempston
• Semi-detached rear extension in Bedford
• Semi-detached rear extension in Henlow

Other work in Ampthill:

• Single-storey rear extension
• Two-storey rear extension
• Kitchen-diner rear extension
• Side return extension
• Wraparound extension
• Glazed rear extension

All rear extensions in Ampthill