Builders in Wales
Find verified builders across 49 Welsh towns. Every listing is cross-checked against Companies House and Google Business Profile. We do not verify trade-body membership — ask the business for its number and check it on the issuing body's register. Free to use, no sign-up.
Credentials to look for in a builder
The credentials worth asking a builder about. We do not verify these ourselves — check the number on the issuing body's own register.
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 49 Welsh towns.
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.