Range from the cheapest single storey extension £39,000 (L.M Landscapes & Driveways based in Tw15) to the dearest single storey extension £54,360 (GDC Design & Build based in TW19).
Comparing extension builders estimates for fitting a downstairs toilet gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to build a single storey extension in TW18 by posting a job with HaMuch and we will send it to extension builders in TW18.
