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Builders in Cardiff

31 practices covering Cardiff. Listings are business information researched by Renovome; contact details and matching happen inside Workspace.

Appointing a builder in Cardiff

Cardiff builders handle rear extensions, loft conversions and refurbishment of Victorian terraces across Cathays, Roath and Canton, plus semis in the northern suburbs. Wales has its own building regulations and planning policy, so confirm your builder works to them routinely.

Property you'll be working with in Cardiff

Bay-fronted Victorian terraces with rear lanes — which often make access and muck-away easier than in London — alongside interwar and post-war semis further out.

Planning in Cardiff

Planning policy in Wales differs from England, and Welsh building regulations apply, including separate sprinkler requirements in some residential conversions. Cardiff Council publishes its own householder guidance.

What builders charge in Cardiff

£2,000 to £2,800 per square metre for a mid-finish extension shell in 2026, and £900 to £1,450 per square metre for a full internal refurbishment.

Indicative 2026 ranges and local context, not quotations or planning advice. Last reviewed: September 2026.

How to choose a builder in Cardiff

You appoint a builder once the scope is defined. If you invite builders before the drawings and specification are settled, every quote prices a different job and you cannot compare them.

  1. Give every builder the same drawings, specification and programme, then compare line by line.
  2. Check the company at Companies House, and ask how long the team has worked together.
  3. Visit a current site, not just a finished photo.
  4. Ask for public liability insurance and, where relevant, a warranty or guarantee.
  5. Agree a payment schedule tied to stages completed, never a large payment up front.

What builders in Cardiff typically work on

  • Single and two-storey extensions
  • Loft conversions and garage conversions
  • Kitchen and bathroom refits
  • Structural openings and knock-throughs
  • Whole-house refurbishments

Typical 2026 fees for builders

ItemTypical 2026 cost
Extension shell, per square metre£2,300 - £3,400
Single-storey rear extension, 20 sq m£52,000 - £86,000
Loft conversion, rear dormer£48,000 - £78,000
Structural opening with flush beam£4,500 - £12,000
Day rate, two-person team£380 - £620

Indicative 2026 UK ranges, not quotations. London and the South East usually sit at the top of each range. Last reviewed: September 2026.

Common questions

How many builders should I ask to quote?
Three is enough, provided all three price the same written scope. More quotes on a vague brief produce a wider spread, not better information.
Why do quotes for the same job differ so much?
Usually because they include different work. Compare the inclusions, exclusions and provisional sums before you compare the totals.

Read next

Brief several builders at once

Renovome Workspace shortlists suitable practices for your project, sends one consistent brief and lays the responses out side by side so you compare scope, not just price.

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