12 Celyn Grove, Cyncoed, Cardiff, United Kingdom CF23 6SH
Building, extensions and refurbishment
Quote on request.
Cardiff · Building & conversions
Builders in Cardiff
Phone numbers for builders covering Cardiff — extensions, loft conversions and refurbishment. Open a profile and call the business yourself. This site does not send your job.
Extensions and loft work need more than a day rate. The renovation budget tool can sit beside a local quote. Barry and Caerphilly on a card are not Roath. The Welsh form of the electrical notification rule applies here; this is not an English Part P form with the city swapped. Profiles show a name, the area they cover and a phone number. Public qualifications such as Gas Safe or NICEIC appear only when they are on the profile. Read the cost notes for a sourced national range; a figure on a card is not a quote.
Desg, 11-13 Penhill Road, Cardiff, Wales CF11 9PQ
Building, extensions and refurbishment
Quote on request.
2 Coed Cochwyn Avenue, Llanishen, Cardiff, Wales CF14 5BS
Building, extensions and refurbishment
Quote on request.
231 Cyncoed Road, Cardiff, Wales CF23 6NY
Building, extensions and refurbishment
Quote on request.
7/8 Raleigh Walk, Waterfront 2000 Brigantine Place, Cardiff CF10 4LN
Building, extensions and refurbishment
Quote on request.
49 Fishguard Road Llanishen, Cardiff, Wales CF14 5PQ
Building, extensions and refurbishment
Quote on request.
Hafod Fan The Close, Llanishen, Cardiff, Wales CF14 5NG
Building, extensions and refurbishment
Quote on request.
2 Brynheulog, Pentwyn, Cardiff, United Kingdom CF23 7JA
Building, extensions and refurbishment
Quote on request.
Portland House, 113-116 Bute Street, Cardiff, Wales CF10 5EQ
Building, extensions and refurbishment
Quote on request.
Clifton House, Four Elms Road, Cardiff, Wales CF24 1LE
Building, extensions and refurbishment
Quote on request.
No businesses match those extra filters. Clear 24-hour or qualification to widen the list.
Typical building & conversions costs
Checkatrade’s house-extension guide, per-square-metre table last updated March 2025, is a national sense-check for shell versus finished work. It is not a local tariff. Loft rooms over Cathays bays have to keep the bay ceiling height. Ask if the steel crosses that bay or if the quote pretends the plan is a rectangle.
A local rule to check in Cardiff
Many extensions, loft conversions and structural openings need building control, and some need planning. A listing is not an approval and not a party-wall agreement.
Questions before you phone
How do I find builders in Cardiff on this list?
Cathays and Roath are bay-fronted terraces used as shared houses. Pontcanna is closer to the river and more likely to be a conservation street. Splott is a different roof and a different parking problem. Names, service areas and phone numbers sit on the cards. Open a profile and call the firm yourself. Barry and Caerphilly on a card are not Roath. The Welsh form of the electrical notification rule applies here; this is not an English Part P form with the city swapped.
Does this page send my job to a Cardiff building & conversions firm?
No. You place the call. This site does not email or text anyone on your behalf.
What should the written price say for building & conversions in Cardiff?
Show the bay on the loft sketch. Headroom there decides the steel.
What is easy to miss before booking in Cardiff?
Bay roofs leak into the front bedroom while the main pitch is sound. A 'roof repair' that does not say 'bay' has not looked at a Cathays terrace.
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