Range from the cheapest single storey extension £47,000 (GENERAL BUILDING SERVICES based in KT1) to the dearest single storey extension £63,000 (A Dawson Building Surveys Ltd based in IM4).
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 Onchan by posting a job with HaMuch and we will send it to extension builders in Onchan.

"Single storey extension"
ISLE OF MAN
| Business name | Single storey extension cost |
|---|---|
| GENERAL BUILDING SERVICES, Kingston upon Thames, KT1 | £47,000 |
| A Dawson Building Surveys Ltd, Higher Foxdale , IM4 | £63,000 |