Building regulations for extensions in Cardiff
We prepare building regulations for extensions for homes in Cardiff, as a stand-alone service or as the first stage of a design and build project.
- Guide price in CardiffFrom £800 inc VAT
- Approval routeFull plans or building notice
- Timescale2–5 weeks for drawings
- Postcode districtsCF5, CF10, CF11, CF14, CF23
Fees in Cardiff
Fees below are our Cardiff guide (×0.93, the Wales factor), including VAT. Council and building control fees are extra.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Building regulations drawings for a simple single-storey extension | £800 – £1,700 |
| Standard | Drawings plus structural calculations | £1,200 – £2,450 |
| Premium | Complex or two-storey pack with energy calculations | £2,000 – £3,550 |
Our design fee only. Building control charges are set by your council (or, in England and Wales, a registered building control approver) and quoted separately.Council fees are extra and are set by the Welsh Government.
Want a range for your exact size? The guide-price tool takes about a minute.
Local to Cardiff
Our survey diary covers Cardiff, including CF5, CF10, CF11, CF14, CF23, CF24. Neighbouring towns we cover include Penarth (3 miles), Barry (7 miles), Cowbridge (12 miles).
Caerphilly, in Mid Glamorgan, is roughly 7 miles from Cardiff and also on our list. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Who this service is for
- Glass-heavy designs that need energy calculations
- Every extension, whatever the planning route
- Homeowners using their own builder who need the drawings
Do I need planning permission in Cardiff?
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
The planning position for a specific Cardiff address depends on its history and any designations, which is why we check it at the first visit.
Building over or within 3 m of a public sewer needs the water company's consent before the foundations go in.
The Party Wall etc. Act 1996 applies in Wales as in England: notice must be served before work to a shared wall, building on the boundary, or excavating close to a neighbour's foundations.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Cardiff
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Cardiff, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with in Cardiff?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will my neighbours in Cardiff be involved?
If a planning application is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Full plans or building notice?
A full plans application gets the drawings checked before work starts, which we usually recommend for extensions. A building notice is quicker to submit but carries more risk if something needs changing on site.
Who are building control?
Either your local council’s building control team or a registered building control approver. Both inspect the work and issue the completion certificate.
Book a free site visit in Cardiff
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.