How long should I expect a typical project to take in Cardiff?

It depends entirely on the job. A kitchen refurbishment takes 3-6 weeks. A single-storey extension takes 12-16 weeks from start to finish, including Planning and Building Control approvals. A full house renovation can take 6-12 months. Weather affects timescales significantly in South Wales. Winter work takes longer because drying times increase and weather delays are common. Rain, frost, and wind can all set you back days or weeks. Always add 10-20% contingency to the quoted timescale. Builders underestimate because they want to win the job, but unexpected issues (hidden structural damage, supply delays, Building Control requests for rework) are normal. A builder who gives you a guaranteed timescale with no flexibility is either inexperienced or lying.

What should a contract with a builder include?

Your contract must cover: the scope of work (exactly what's being done, with specifications), the total cost (broken down by labour and materials), the timescale (start and end dates, or 'approximately X weeks'), payment schedule (when you pay and how much), how changes are handled (written request, new quote, signed amendment), insurance details (public liability, employer's liability if they have staff), Building Control and Planning responsibilities, and what happens if work is defective. It should also cover how disputes are resolved (many builders now use mediation or arbitration clauses), liability limits, and what happens if either party needs to withdraw. Include a clause about keeping the site clean and safe. Use a standard contract form if possible. The FMB has templates, as does the RIBA (Royal Institute of British Architects). Don't sign anything without reading it carefully. If you don't understand something, ask a solicitor—it's money well spent.

How much deposit should I pay upfront?

Standard practice is 10-20% upfront. This covers the builder's initial costs (materials ordered, site setup). Don't pay more than 20%—if a builder insists on 50% or more, it's a red flag. The remaining balance should be paid in stages tied to work completion. For example: 50% when first fix is done (electrical and plumbing installed), 30% when snagging is complete, final 10-20% after Building Control sign-off and you've inspected everything. Never pay the final amount before Building Control approval. This is your only leverage to ensure work is completed to standard. Once you've paid in full, the builder has no reason to come back and fix problems. If anything goes wrong after final payment, disputes become much harder and more expensive to resolve.

What's the difference between Planning Permission and Building Control approval?

Planning Permission is about whether your development is acceptable to the council from a land-use perspective. It checks whether the work fits with local planning policy, doesn't harm neighbours' amenity, and follows design guidelines. It's applied for before work starts and can take 8-13 weeks. Building Control approval is about safety and standards. It checks whether the work meets current building regulations—structural safety, fire safety, electrical standards, and so on. Building Control inspects the work at key stages (foundations, first fix, completion) and signs it off when complete. You need both for most structural work. Your builder should handle both applications, but the costs and timescales are separate. Planning can be refused (in which case you redesign and reapply); Building Control approval is granted if you meet the standards, though they may ask for rework if standards aren't met.

What should I do if there's a dispute with my builder?

First, try to resolve it directly. Speak to the builder, put your concern in writing (email is fine), give them a reasonable opportunity to fix it. Many disputes are simple misunderstandings. If direct negotiation fails and the contract includes a mediation clause, use it. Mediation is faster and cheaper than court. If there's no mediation clause, your next steps are: contact the builder's accreditation body (FMB, TrustMark, or Which?), which often has dispute resolution procedures; or seek legal advice about whether you have grounds for small claims court. Keep all documentation: quotes, contracts, photos, emails, invoices, and notes of conversations. If Building Control has inspected work and found it defective, that's official documentation supporting your case. If the builder is FMB or TrustMark registered and fails to resolve the dispute properly, their accreditation body can enforce standards and even revoke membership. This is another reason accreditation matters—it gives you recourse.

Cardiff builders 2026, Costs, Free Quotes, Vetted Pros

What to know before hiring a builder in Cardiff

Hiring a builder is one of the biggest decisions you'll make as a homeowner. Get it right and you'll have quality work, on time and on budget. Get it wrong and you're looking at delays, poor workmanship, and arguments about money.

This guide is written for Welsh homeowners in Cardiff who need practical, no-nonsense advice. We've focused on what actually matters: what builders cost in 2026, which accreditations are worth checking, and the specific questions you need to ask before you sign anything.

Whether you're doing a kitchen extension, a full renovation, or just fixing structural issues, the principles are the same. A good builder will have references you can speak to, proper insurance, and a clear contract. They won't rush you, they won't cut corners, and they'll communicate with you regularly.

Cardiff's housing stock is mixed—Victorian terraces, post-war semis, and modern estates. Each type brings different challenges and costs. Your builder needs to understand your property type and the common issues that come with it.

Take your time hiring. The cheapest quote is rarely the best value. A builder who charges more but finishes on time and does quality work will save you money and stress in the long run.

What builders charge in Cardiff in 2026

Builder costs depend on the job type and complexity. Here's what you should expect to pay in 2026:

Labour rates: Most Cardiff builders charge £150-£250 per day for skilled work, or £35-£65 per hour. Specialists like roofers or electricians cost more—expect £200-£300+ per day. These rates vary by experience and the nature of the work.

Extensions: A single-storey rear extension (4m x 4m) typically costs £25,000-£45,000 depending on specification and your property type. Two-storey extensions run £40,000-£70,000+. These figures include labour, materials, and basic finishes.

Renovations: A full kitchen refurbishment costs £8,000-£20,000. A bathroom typically runs £5,000-£15,000. A full house renovation (rewiring, replumbing, new heating, decoration) on a mid-sized Cardiff terrace can be £80,000-£150,000+.

Roofing: Replacing a roof on a standard semi-detached house costs £7,000-£12,000. Slate (common on older Cardiff properties) costs more—£12,000-£18,000.

Structural work: Underpinning, cavity wall ties, damp remediation—these are costly and specific. Budget £5,000-£25,000+ depending on severity and property size.

VAT: Remember that standard-rated work is subject to 20% VAT. Some renovation work qualifies for zero-rated VAT if your property is over two years old—ask your builder about this.

Always get three written quotes. Prices should include materials, labour, and VAT. If one quote is significantly cheaper, ask why before accepting it.

Accreditations and credentials that matter

Not all accreditations are equal. Here's what to look for and why it matters:

FMB (Federation of Master Builders): This is the gold standard for general builders in the UK. FMB members commit to a Code of Conduct, carry proper insurance, and must have provable experience. An FMB-registered builder has been vetted and can be held accountable if things go wrong. Check the FMB website—you can verify membership instantly.

TrustMark: Run by the government, TrustMark certifies traders across the built environment. Builders with TrustMark status have been properly checked and have consumer protection built in. If a TrustMark trader fails to complete work properly, you have a formal dispute process.

Which? Trusted Trader: Consumer organisation Which? vets traders independently. This badge means the trader has been checked for insurance, qualifications, and customer feedback. They also handle complaints if things go wrong.

NHBC Warranty: If your builder is NHBC-registered, any new build work comes with a structural warranty. This protects you after completion.

Building Control approval: Any structural work must be signed off by Building Control. Your builder should arrange this or confirm it's been done. Never skip this—it affects future insurance and resale value.

Specialist certifications: For electrical work, check Part P certification. For gas, check Gas Safe. For boilers and heating, look for OFTEC or similar.

Don't assume a trader is safe just because they're not accredited, but accreditation makes it much easier to enforce standards if something goes wrong.

Cardiff-specific things your builder needs to know

Cardiff's housing is varied and brings specific issues that affect both cost and timeline.

Victorian and Edwardian terraces: These make up much of inner Cardiff (Canton, Cathays, Roath). They're often built with solid brick walls, poor insulation, and original timber windows. Damp is common, especially in basements. Rising damp, penetrating damp, and condensation are frequent problems. Your builder needs experience with lime mortar, traditional ventilation, and damp remediation. Modern solutions (like impermeable renders) can cause more problems than they solve on these properties.

Subsidence risk: Parts of Cardiff, especially areas built on clay, are affected by previous mining. The Coal Authority has records. Any crack wider than 5mm should alarm you. A good builder will know how to assess this and when to call in a structural engineer.

Listed buildings: Many Cardiff properties are listed, especially in the city centre and Llandaff. Alterations to listed buildings need Listed Building Consent, separate from Planning Permission. Your builder must be familiar with this process—it adds time and cost.

Building Control: Cardiff Council's Building Control is reasonably responsive but can be slow during busy periods. Budget extra time and inspection fees. Your builder should manage this relationship, not leave it to you.

Local materials: Some Cardiff builders have relationships with local suppliers and salvage yards (useful for matching materials on older properties). Others don't. Ask about their supply chain—it affects both cost and timeline.

Weather: South Wales gets significant rainfall. Drying times for plaster, paint, and external work are longer than you might think. Winter builds take longer.

Choose a builder who knows Cardiff specifically. They'll anticipate problems and manage timelines better.

How to hire a builder in Cardiff

Follow this process to reduce risk:

Step 1: Get recommendations: Ask friends, family, and neighbours about builders they've used. Ask specifically what went well and what didn't. Personal experience is more reliable than online reviews.

Step 2: Get written quotes: Contact at least three builders. Give each the same brief (written, with photos if possible). Ask for quotes that break down labour, materials, and timescales. Unusually low quotes deserve scrutiny—ask why.

Step 3: Check credentials: Verify FMB membership, TrustMark status, or Which? registration. Ask for proof of public liability insurance (minimum £6 million for most work). Ask for references and actually contact them.

Step 4: Meet the builder: This matters. You'll be living with this person for weeks or months. Are they professional? Do they listen? Do they answer questions clearly? Do you trust them? Don't ignore your gut feeling.

Step 5: Get a detailed contract: Before work starts, you need a written contract that covers: scope of work (what's included, what isn't), timescale, payment schedule, how changes are handled, insurance details, and dispute resolution. Don't start work without this.

Step 6: Agree payment terms: Never pay the full amount upfront. Standard terms are: deposit (10-20%), progress payments (tied to milestones), final payment on completion. Get Building Control sign-off before final payment.

Step 7: Stay involved: Regular site visits, clear communication, and documented changes prevent problems. If something looks wrong, raise it immediately.

Take your time. Rushing this process costs more money later.

Eight questions to ask any builder before hiring

Ask these questions and listen carefully to the answers:

1. "Can you show me proof of public liability insurance?" You need copies. Minimum cover is £6 million. If they won't show you, don't hire them.

2. "Can you give me three recent references I can contact?" Ask for references from jobs completed in the last 12 months. Call them. Ask whether work was on time, on budget, and whether they'd hire them again.

3. "How long have you been trading and what's your experience with [your property type]?" A builder with 20 years' experience on Victorian terraces is better than a generalist for that job. Experience matters.

4. "What happens if the job takes longer than planned?" Bad weather, unexpected structural issues, or supply delays happen. How will they communicate delays? Will costs increase? What's the process?

5. "How do you handle changes during the job?" You might want to change something mid-way. Ask how they price changes, how it affects the timeline, and whether it needs writing down.

6. "Will you arrange Building Control inspections or am I responsible?" Most builders arrange this. Confirm it's their responsibility and cost.

7. "What's your payment schedule?" Should be tied to milestones, not time. First fix (electrics, plumbing installed) is a good checkpoint. Final payment after sign-off.

8. "What happens if something goes wrong after you've finished?" Ask about warranty and snagging lists. Most offer 12 months' warranty on labour.

If they're evasive on any of these, that's a warning sign.

Cardiff builders — the complete homeowner guide (2026)