House Extension Build / Construction Cost

Extensions can vary greatly in shape, size and budget so whether you are planning a simple pitched roof extension or a larger project costs can start to add up very quickly and getting the right design can save your build time and money!

From our knowledge a basic single storey extension would typically cost between £1,200m2 to £1,600m2, so a 3m x 5m extension would cost between £18,000 to £24,000 and from £50,000 for a two storey extension. These costs are just to create a room, they would not typically include the cost of a kitchen or bathroom.

This average cost should cover design through to decorating of standard rooms, but it is worth having a 10-15% contingency to cover unexpected costs.

There is also a third party Extension Cost Calculator below that could help you: -

https://www.homebuilding.co.uk/advice/extension-cost-calculator

Here at Extension Drawings Ltd, we can design your extension to meet your budget, whilst suggesting design ideas to maximise your layout.