How to Deal With a Bad Builder UK: A Step-by-Step Guide

A bad builder experience is one of the most stressful things that can happen to a homeowner. Whether it's poor workmanship, a contractor who's gone quiet mid-project, or a dispute over money, the principles are the same: document everything, escalate calmly and methodically, and know exactly what your options are before you need them.

This guide covers prevention first, then walks you through the escalation ladder from informal complaint to court.

1. Prevention First

The best time to deal with a bad builder is before you hire one. These protections cost little to put in place and matter enormously if things go wrong.

The JCT Minor Works Contract

The JCT Homeowner Contract (available from the JCT at jtc.org) is designed for renovation and refurbishment projects up to £250,000. It establishes:

• Scope of works — what is included and excluded
• Contract sum — the agreed price (or budget for a cost-plus arrangement)
• Completion date — with provision for liquidated damages if the contractor overruns
• Payment schedule — how and when payments are made
• Defects period — typically 3–6 months post-completion, during which the contractor must return to remedy defects
• Dispute resolution — adjudication or arbitration provisions

A contractor who refuses to sign any form of written contract is a contractor to avoid.

Stage Payments vs Upfront Payment

Never pay more than 10–25% upfront. A larger upfront payment reduces your leverage if work is poor or abandoned. Structure payments around milestones:

• 10–15% on mobilisation (to cover material ordering)
• 25–30% at structural completion
• 25–30% at first fix (or plasterboard)
• 20–25% at practical completion
• 5–10% retention for 3–6 months post-completion

Any contractor demanding 50%+ upfront without a strong reason (bespoke material ordering, for example) is a warning sign.

Written Variations

All changes to the agreed scope — however minor — must be agreed in writing before work proceeds. A simple WhatsApp message confirming the variation and its agreed cost is sufficient. "My contractor said it would only cost a bit more" is not a defensible position if the variation bill is double what you expected.

2. Types of Problems

Understanding which category your problem falls into helps you choose the right response:

Poor workmanship: Work completed but not to a satisfactory standard — cracked tiling, uneven plastering, leaking joints, structural work that doesn't comply with Building Regulations.

Delays: Work proceeding more slowly than agreed, or contractor off-site for extended periods without explanation.

Abandoned site: Contractor has stopped attending and is uncontactable. This is the most urgent situation — you may have open structure exposed to weather.

Overcharging: Final account significantly exceeds agreed contract sum without legitimate variations to justify the difference.

Damage to property: Contractor has damaged your home, contents, or adjacent structures during works.

3. The Escalation Ladder

Step 1: Document Everything (Start Before Problems Arise)

Before raising any formal complaint, ensure your documentation is in order:

• Photographs: Dated photos of work at each stage. If you're in dispute, photograph defects from multiple angles with a scale reference.
• WhatsApp/email records: Save all correspondence. Screenshot WhatsApp chats (messages can be deleted by the other party).
• Daily diary: A contemporaneous diary noting what work was done each day, who was on site, and any concerns raised — even informally.
• Invoices and receipts: All payments made with dates and amounts.
• Original quote and contract (if any): The document against which workmanship and scope disputes are judged.

If you're not already doing this, start today — even if there's no current problem.

Step 2: Formal Written Complaint to the Contractor

Before escalating externally, give the contractor a formal written opportunity to rectify. Send by recorded delivery (Royal Mail Signed For or Special Delivery) so you have proof of receipt.

Your letter should:

1. State clearly what the problems are with specific reference to the scope of works
2. Refer to photographs and any specific clauses in the contract
3. Request a written response within 14 days
4. State that if the issues are not addressed, you will pursue the matter through the relevant trade body and/or the courts

Keep the tone professional and factual — emotion rarely helps at this stage.

Step 3: Trade Body Complaint

If you hired a contractor registered with a recognised trade body, that body has a complaints and conciliation process:

Trade body conciliation is free or low-cost, faster than court, and often results in remediation without formal proceedings. The contractor's membership depends on maintaining good standing, which is a real incentive to engage.

Step 4: Alternative Dispute Resolution (ADR)

If direct negotiation and trade body conciliation fail, ADR offers a formal but non-court route to resolution.

RICS Adjudication: For disputes involving RICS members (surveyors, project managers) or under JCT contracts with adjudication clauses, RICS provides adjudication under the Scheme for Construction Contracts. An adjudicator's decision is temporarily binding and enforceable in court.

CTSI-approved ADR schemes: The Chartered Trading Standards Institute (CTSI) approves ADR schemes across sectors. TrustMark's scheme covers most residential building trades.

Ombudsman Services: Some trade bodies have access to ombudsman services — check your specific trade body.

ADR is typically faster (8–12 weeks) and cheaper than court. If you proceed to court subsequently, evidence from ADR can be used.

Step 5: Small Claims Court

For disputes up to £10,000, the Small Claims track in the County Court (England and Wales) offers a straightforward, low-cost route to judgment.

How it works:

1. File a claim online at gov.uk/make-court-claim-for-money
2. Fee: £25–£455 depending on claim amount (sliding scale)
3. The defendant has 14 days to respond; 28 days to file a Defence
4. Most small claims are settled before the hearing once the claim is filed
5. If defended, a hearing date is set — typically 3–6 months from issue
6. You don't need a solicitor in Small Claims, though legal advice is useful beforehand

Important: Before issuing a claim, send a Letter Before Action (also called a Letter Before Claim) giving the other party a final opportunity to resolve. Courts expect this step to have occurred.

Step 6: County Court (Claims Over £10,000)

For claims above £10,000, the matter moves to the Fast Track (£10k–£25k) or Multi-Track (above £25k). Legal costs become more significant and the proceedings more complex. Consider instructing a solicitor, particularly if the other side is likely to defend vigorously.

Enforcement of judgment: Winning a judgment is only the first step — you then need to enforce it if the contractor doesn't pay. Options include:

• Attachment of earnings
• Charging order on the contractor's property
• Instructing High Court Enforcement Officers (bailiffs) — requires registering the judgment with the High Court first (for claims over £600)

4. Independent RICS Defects Survey

Before bringing any formal claim, commission an independent defects survey from a RICS-regulated building surveyor. This is one of the most powerful tools available to a homeowner in dispute.

Cost: £500–£2,000 depending on property size and scope of defects.

What it covers:

• Identification and description of all defects
• Assessment of whether they represent a departure from reasonable workmanship and/or Building Regulations
• Estimated cost to rectify each defect
• Photographs with annotations

How to use it:

• Attach it to your formal complaint letter
• Submit it in your ADR or court claim as expert evidence
• Use the rectification cost estimate as the basis of your claim amount

A surveyor's report dramatically strengthens your position in any dispute — it converts "I think this is wrong" into an independent professional opinion with a costed remedy.

5. Stopping Payment

Withholding payment is a legitimate tool, but must be used carefully. Under the JCT Minor Works Contract (and under the Housing Grants, Construction and Regeneration Act 1996 for contracts over £250), you have the right to serve a Pay Less Notice if you intend to pay less than the sum notified by the contractor.

Key principles:

• You cannot simply withhold payment without giving written notice
• Your notice must state the sum you propose to pay and the basis for the reduction
• You must serve the notice within the timeframes in the contract
• Set-off is available where you have a genuine counter-claim (e.g. cost to rectify defects)

For contracts without formal payment mechanisms, you can withhold payment for:

• Defective work (to the value of the cost to rectify)
• Liquidated damages for delay (if agreed in contract)
• Damage caused by the contractor

Do not withhold payment for anything that isn't quantified and documented. Blanket non-payment can expose you to a counter-claim.

6. Getting Another Builder In

When a contractor abandons a project or you terminate the contract due to material breach, you'll need a new contractor to complete the works. This creates a specific set of challenges:

Documentation of existing works: Before the new contractor starts, commission a schedule of condition documenting the state of every element of the existing works. Photograph and measure everything. This is the baseline for any subsequent defects claim against the original contractor.

New contract terms: Your new contractor should agree in writing that any additional costs arising from defects in the existing works (additional materials, making good, re-doing work) will be documented separately from the completion works. This creates a clear evidential record for your claim.

No guarantee of quality: The new contractor is not responsible for what was done before they arrived. They will need to assess the existing works and may find problems the original contractor concealed.

7. What You Cannot Do

Self-Help Remedies

You cannot unilaterally instruct a third party to undo or replace the contractor's work and then deduct the full cost from what you owe, without following the proper contractual process. Do it wrong and you may convert yourself from claimant to defendant.

Social Media and Defamation

Posting negative reviews or social media posts about a contractor can be defamatory if you state facts that are untrue or inaccurate. Stick to documented facts. "The roof leaked" is a fact. "He is a fraudster" without a fraud conviction is potentially defamatory. Keep all public commentary factual and measured.

Threatening Counterclaims

Do not threaten to "bring a counterclaim" in response to a contractor's demand unless you have taken legal advice. Empty threats look unserious and can damage your credibility.

Template Complaint Letter Outline

This is a structural outline only. For a full legal template, consult Citizens Advice (citizensadvice.org.uk) or a solicitor.

[Your name and address] [Date]

[Contractor's name and address]

Re: Formal Complaint — [project address] — Contract dated [date]

Dear [Contractor name],

Paragraph 1 — Introduction I write to formally set out my concerns regarding the works carried out at [address] under our agreement of [date], a copy of which is enclosed.

Paragraph 2 — Summary of defects / issues I have identified the following specific problems with the works: [list each item clearly, with reference to photos attached as appendices]. These represent a departure from the agreed specification / reasonable standard of workmanship / Building Regulations as set out in [specify].

Paragraph 3 — Requested remedy I require you to [rectify the specified defects / provide a written explanation / return to site to complete outstanding works] within 14 days of the date of this letter.

Paragraph 4 — Next steps If I do not receive a satisfactory response within 14 days, I will pursue this matter via [the relevant trade body / Alternative Dispute Resolution / the courts] and will seek recovery of all costs incurred, including the cost of independent rectification works.

Yours sincerely, [Signature]

Facing a contractor dispute? Renovate Me helps you manage your project with the documentation tools, checklists, and supplier tracking to protect yourself from day one.