Range from the cheapest single storey extension £43,800 (Eco Construction Systems Ltd based in CH42) to the dearest single storey extension £143,000 (G R T building&roofing based in L13).
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 Liverpool by posting a job with HaMuch and we will send it to extension builders in Liverpool.

"Single storey extension"
LIVERPOOL
"L shape extention with doom loft"
L4