Range from the cheapest Loft conversion £30,000 (P & M Builders based in RM7) to the dearest Loft conversion £45,000 (Optimus Build Solutions based in Rm1).
Comparing extension builders estimates for Loft conversion 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 for the cost of a loft conversion in Collier Row by posting your job to extension builders in Collier Row.

"Loft conversion"
ROMFORD
"Velux Loft conversion for a terraced house in Romford. Just turning into a multi space room. Office/ kids chill area. No bathroom needed."
RM7