How to sue a builder for bad workmanship in the UK (Small claims guide)
The short answer: you can sue a builder in the County Court (Small Claims Track for claims up to £10,000) for breach of Section 49 of the Consumer Rights Act 2015, which implies a statutory term into every building contract that the work must be carried out with "reasonable care and skill". To win, you do not need an expensive solicitor, but you do need: (1) photographic proof of defects, (2) two or three written quotes from independent builders for rectification, (3) a structured Scott Schedule, and (4) an independent RICS surveyor report for technical or structural disputes.
REVIEWED BY: Sean McNamara on 2026-09-03
The legal foundation: Section 49 Consumer Rights Act 2015
When building work is defective, cracked, out of plumb, or substandard, the law is on your side:
- Section 49 CRA 2015: Every contract to supply a building service includes a mandatory implied term that the builder must perform the work with reasonable care and skill. This cannot be excluded by any contract term or small print.
- Section 55 (Right to Repeat Performance): The consumer has a statutory right to require the builder to redo or rectify defective work at the builder's own expense, within a reasonable time and without significant inconvenience.
- When you can bypass repeat performance: You are not required to let the original builder touch the property again if: 1. It is impossible for them to rectify the work properly; 2. They have failed repeatedly or caused significant inconvenience; 3. The work is dangerous, structurally compromised, or in breach of Building Regulations; 4. Trust has broken down completely due to abusive behaviour, abandonment, or aggressive demands.
- Section 56 (Right to Price Reduction & Damages): Where repeat performance is impossible or inappropriate, you are entitled to a price reduction (which can be up to 100% of the contract sum) plus consequential damages to pay another contractor to rectify the defects.
What evidence decides a bad workmanship claim?
County Court judges are not builders; they rely strictly on documentary and technical evidence. In order of evidential weight:
1. Independent RICS Surveyor's Report
For claims involving structural movement, damp ingress, roof defects, or major plastering/brickwork failures, an independent report from a RICS Chartered Building Surveyor is gold standard evidence.
- Under CPR Part 35, expert reports must state they are independent and owe their primary duty to the court, not to you.
- In the Small Claims Track, you can claim up to £750 towards the cost of an expert report if you win, pursuant to CPR 27.14(2)(g).
2. Two to Three Independent Rectification Quotes
Judges require proof that your claimed repair figure is reasonable market value:
- Obtain 2 or 3 formal, written, fully itemised quotes from reputable local builders to strip out and rectify the defective work.
- The average of these competitive quotes establishes your "Cost of Cure" under standard contract law.
3. The Scott Schedule
In construction litigation, courts expect defects to be presented in a Scott Schedule (a standardised defect table):
| Item # | Location | Nature of Defect | Contract / CRA Reference | Rectification Required | Independent Quote Cost |
|---|---|---|---|---|---|
| 1 | Bathroom | Shower tray not bedded; leaking into kitchen below | CRA 2015 s.49 (lack of skill) | Remove tray, replace rotted joist, refit | £1,450 (Quote A) |
| 2 | Kitchen Ext. | Sub-floor concrete 35mm out of level across 4m | BS 8204-1 tolerance breach | Apply smoothing compound / screed | £850 (Quote B) |
| 3 | Rear Wall | Brickwork ties missing; cavities blocked with mortar | Building Regs Part A breach | Rake out mortar, insert retro-ties | £2,100 (Quote A) |
4. Photographic & Video Evidence Log
- High-definition photographs with date-stamps.
- Use a spirit level, ruler, or coin in photos to demonstrate out-of-plumb walls, uneven tiles, or gap widths.
Step-by-Step: The Small Claims Court Roadmap
Step 1: Pre-Action Letter Before Claim
Under the court's Pre-Action Protocol, you must send a formal Letter Before Action giving the builder 14 days (or 28 days for complex construction claims) to pay the rectification costs or reach a settlement. Enclose your Scott Schedule and photographic summary.
Step 2: Issue the Claim Online (MCOL)
If the builder ignores you or refuses to pay: 1. File your claim online via GOV.UK Money Claims Online. 2. For claims up to £10,000, the case is allocated to the Small Claims Track. 3. State your Particulars of Claim clearly: > "The Claimant claims damages of £[sum] for breach of contract and breach of Section 49 of the Consumer Rights Act 2015 in respect of defective building works at [address], as detailed in the attached Scott Schedule, plus statutory interest pursuant to Section 69 County Courts Act 1984 at 8% per annum (£[interest sum]), plus court fees."
Step 3: Free Small Claims Mediation
Once the builder files a defence, HMCTS will offer a free 1-hour telephone mediation appointment with a court mediator. Over 60% of small claims settle at this stage without ever stepping foot inside a courtroom.
Step 4: Prepare the Court Hearing Bundle
If mediation fails, the court will order both parties to file and serve their witness statements and document bundles typically 14 days before the hearing.
Your bundle should contain:
- Chronological timeline of the project;
- The original quote, contract, and proof of payments;
- Your Scott Schedule of defects;
- Independent surveyor report and remedial quotes;
- Indexed and paginated photographic exhibits;
- Copies of all written communications (WhatsApp, emails, text messages).
Related guides & tools
- Schedule of loss guide — calculate your total damages
- Letter before action builder template — pre-action protocol letter
- Small claims hearing day walkthrough — what happens before the judge
- Court fee calculator — calculate court issue fees
- Builder walked off the job — what to do — repudiatory breach guidance
This guide provides general procedural information for England & Wales and is not formal legal representation. Sourced from the Consumer Rights Act 2015 and Civil Procedure Rules (CPR Part 27). Verified 2026-09-03.
Turning your evidence into a court-ready bundle? EvidenceCanvas (Casewright) helps you organise your evidence and draft pre-action documents for the small claims track. It is not a law firm and does not give legal advice.
Reviewed by Sean McNamara · 2026-09-03 · Independent information directory — not legal advice.