Builders in Wales
Find verified builders across 60 Welsh towns. Every listing is cross-checked against Companies House and the credentials that matter for builder work, FMB, TrustMark, NHBC. Free to use, no sign-up.
Credentials to look for in a builder
The badges that prove a builder is qualified for the job. We confirm these before a listing earns a Verified badge.
Read the rules: Pre-hire checklist, verifying any Welsh tradesperson · TrustMark, FMB & builder vetting in Wales · Welsh Building Regulations 2026, extensions, conversions, council fees
What a builder costs in Wales
- Single storey extension
- £20,000–£50,000
- Loft conversion
- £25,000–£60,000
- Garage conversion
- £8,000–£20,000
Find builders near you
Browse verified builders town by town across all 60 areas of Wales.
South Wales
Common questions
How much does a single-storey extension cost?
Typically £20,000–£50,000 depending on size, finish and groundworks. Get an FMB or TrustMark builder and a written spec.
How much does a loft conversion cost?
Usually £25,000–£60,000 for a dormer loft, including stairs, insulation and building control.
Do I need planning permission?
Many extensions fall under permitted development, but always check with your local Welsh council first.