Extension builders in Cardiff
Firms in Cardiff who list single and double storey, side return and wraparound extensions, ranked by verified customer reviews and then distance. Nobody pays to move up this list, and a message goes to the one builder you choose.
No builders match these filters for kitchens and bathrooms in CardiffSorted by verified reviews, then distance. Never by payment.
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Before you contact a builder
Our guide to extension builders covers what the job involves, the approvals it needs and what to check before you hire. For prices, read House extension cost in the UK (2026 prices). Local planning, building control and housing notes are on the Cardiff page.