Range from the cheapest single storey extension £36,600 (Building & Flat Roofing Contractors based in LL54) to the dearest single storey extension £37,400 (WJ Builders based in LL53).
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 Gwynedd by posting a job with HaMuch and we will send it to extension builders in Gwynedd.

| Business name | Single storey extension cost |
|---|---|
| WJ Builders, Pwllheli, LL53 | £37,400 |
| Building & Flat Roofing Contractors, Caernarfon, LL54 | £36,600 |
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Single Storey Extension near Conwy | £26 | £212 |
| Single Storey Extension near Conway | £22 | £173 |
| Single Storey Extension near Llandudno | £22 | £173 |
| Single Storey Extension near Colwyn Bay | £26 | £212 |
| Single Storey Extension near Rhyl | £24 | £178 |