A flat roof extension is a great way to add extra space to your home without splashing out on the costs of a pitched roof extension. Often exempt from planning permission rules, you can build a flat roof extension up to 3 metres in height as long as it's not visible from a road. But how much do they cost in M40?

A flat roof extension ranges from the cheapest of £21,560 (H TIMMINS BUILDING & MAINT based in M18) to the dearest of £21,664 (Pillo rooms based in M8), but these are just estimates. While they give you an idea of who will be better value, the best way to compare costs is to get real quotes. 

Find out how much your flat roof extension will cost in M40 by posting a job with HaMuch. We'll send it to extension builders in M40.