How to Write a Contract for a Building Job
Most tradespeople never use a written contract. They agree a price, shake hands, and get on with the job. And most of the time that works fine.
But when it doesn’t — when a customer disputes the price, refuses to pay, or claims the work wasn’t what they agreed to — the absence of a written contract leaves you with very little protection.
A simple written contract doesn’t need to be complicated or written by a solicitor. It just needs to clearly set out what was agreed, what it costs, and what happens if things go wrong. Done properly, it protects both you and your customer and prevents the kind of disputes that cost tradespeople thousands every year.
This guide walks you through exactly how to write a contract for a building job — what to include, how to structure it, and how to use it professionally without making customers feel like they’re signing their life away.
Why Tradespeople Need Written Contracts
Before getting into the detail, it’s worth understanding what a contract actually does for you.
It sets clear expectations A written contract means both you and the customer have agreed — in writing — exactly what work is being done, what’s included, what’s excluded, and what it costs. There’s no room for “I thought that was included” conversations later.
It protects you if a customer doesn’t pay If a customer refuses to pay and you need to take action — through the Small Claims Court or a debt recovery service — a signed contract is your strongest piece of evidence. Without it, it’s your word against theirs.
It protects you from scope creep Customers sometimes try to add extra work without acknowledging it should cost more. A contract that clearly defines the scope of work makes it straightforward to say “that’s outside what we agreed — here’s the cost for the additional work.”
It looks professional Presenting a clear, professional contract builds confidence. Customers who might have hesitated about a large project feel more comfortable when they can see exactly what they’re signing up for.
What to Include in a Contract for a Building Job
You don’t need legal jargon or a ten-page document. A clear, straightforward contract covering the following points is sufficient for most trade jobs.
1. Your Business Details
Include your full name or business name, address, phone number, email address, and any relevant registration numbers — Gas Safe, NICEIC, Companies House if you’re a limited company.
2. Customer Details
The customer’s full name and address — including the address where the work is being carried out if it’s different from their home address.
3. Date of the Contract
The date the contract is agreed and signed.
4. Description of the Work
This is the most important section. Be as specific as possible about exactly what work you will carry out.
Don’t write “bathroom refurbishment.” Write:
“Remove existing bath, toilet, and basin. Supply and fit new shower enclosure, back-to-wall toilet unit, and pedestal basin. Tile walls to full height with customer-supplied tiles. Tile floor with customer-supplied tiles. Connect all pipework and test. Make good any areas disturbed in the course of the works.”
The more specific you are, the less room there is for dispute.
5. What’s Not Included
Just as important as what you will do is what you won’t do. Clearly listing exclusions prevents customers from claiming work was included when it wasn’t.
Common exclusions to list:
- Making good plasterwork beyond the immediate work area
- Decorating after the works are complete
- Removing or disposing of customer-supplied materials
- Any work that becomes necessary as a result of unforeseen conditions discovered during the job
6. Materials
Specify who is supplying materials — you or the customer. If you’re supplying, note whether the price is fixed or subject to change based on material costs at the time of purchase.
If the customer is supplying materials, make clear that delays caused by late delivery of customer-supplied materials are outside your control and may affect your programme.
7. Price and Payment Terms
State the total price clearly — including whether it’s VAT inclusive or exclusive. If you’re VAT registered, show the net price, VAT amount, and gross total separately.
Set out your payment terms clearly:
- Deposit amount and when it’s due — for example, 30% on signing
- Stage payments if applicable — for example, 40% on completion of first fix
- Final payment on completion — for example, 30% on practical completion
- Payment method — bank transfer, card, cash
- Payment due date — for example, within 7 days of invoice
8. Programme and Start Date
State your expected start date and an estimated completion date — making clear that the completion date is an estimate and subject to factors outside your control such as weather, material availability, and unforeseen site conditions.
9. Variations
Include a clause explaining how changes to the agreed scope of work will be handled. Something like:
“Any variations to the agreed scope of work will be agreed in writing between both parties before work proceeds. Variations may affect the contract price and programme.”
This is your protection against customers asking for extras and then refusing to pay for them.
10. Disputes and Complaints
Include a simple process for raising and resolving complaints — for example, that any issues should be raised in writing within a set number of days of completion, and that you will respond within a set timeframe.
You might also reference an alternative dispute resolution scheme — some trade associations offer mediation services for their members.
11. Cancellation Terms
What happens if the customer cancels after you’ve started? Or after you’ve ordered materials? Include a clear cancellation clause covering:
- Notice period required for cancellation
- What costs are recoverable if the customer cancels — materials ordered, work already completed
- Your right to retain the deposit if the customer cancels without reasonable notice
12. Signatures
Both parties should sign and date the contract. Each party should keep a copy.
A Simple Contract Template Structure
Here’s how a basic contract might be structured:
CONTRACT FOR BUILDING WORKS
Contractor: [Your name / business name / address / contact details]
Customer: [Customer name / address]
Date: [Date]
Address of works: [If different from customer address]
1. Description of Works [Detailed description of exactly what work will be carried out]
2. Exclusions The following are specifically excluded from this contract: [List exclusions]
3. Materials [Who supplies materials, and any relevant conditions]
4. Contract Price The total price for the works described above is £[amount] [plus VAT at 20% = £[VAT amount] / inclusive of VAT].
5. Payment Terms
- Deposit of £[amount] due on signing
- Balance of £[amount] due within [X] days of completion
- Payment by [bank transfer / card / cash]
6. Programme Expected start date: [date] Estimated completion: [date] — subject to [conditions]
7. Variations Any changes to the agreed scope of work must be agreed in writing before proceeding.
8. Cancellation [Your cancellation terms]
9. Disputes [Your complaints and dispute resolution process]
Signed by Contractor: _________________________ Date: _________
Signed by Customer: _________________________ Date: _________
How to Present a Contract to Customers
The way you present a contract matters. Done right, it builds confidence. Done wrong, it can make customers feel like you don’t trust them.
Keep the language simple Write your contract in plain English. If a customer has to read a sentence three times to understand it, rewrite it.
Walk them through it Don’t just hand over a document and ask for a signature. Take five minutes to walk the customer through what’s in it — what work is included, what’s excluded, the payment terms. This demonstrates professionalism and gives them the opportunity to raise any questions before work starts.
Use a digital signing tool Tools like DocuSign or Adobe Sign let customers sign contracts electronically from their phone. It’s faster, more convenient, and means you get a signed copy back immediately rather than chasing a piece of paper.
Include it with your quote The best approach is to send your contract alongside your quote — so the customer can review both together and sign when they accept the quote. Tradify lets you attach documents to quotes and send them professionally in one go.
What to Do if a Customer Refuses to Sign
Occasionally a customer will resist signing a contract — particularly for smaller jobs. How you handle this depends on the size and risk of the job.
For small jobs — a few hundred pounds — it’s probably not worth making it a sticking point. A detailed quote that the customer accepts in writing (even by email or text) provides some protection.
For larger jobs — anything over £1,000 — a signed contract is worth insisting on. If a customer refuses to sign a reasonable contract, that’s a red flag worth taking seriously before you commit to the work.
The Bottom Line
A written contract doesn’t have to be complicated or intimidating. It just needs to clearly set out what was agreed so that both you and your customer know exactly where you stand.
Start with the template structure in this guide, adapt it to your trade and the types of jobs you do, and use it consistently from day one. The first time it saves you from a disputed invoice or an unpaid bill, you’ll wonder why you ever worked without one.
And once you’ve got your contracts sorted, make sure your quotes and invoices are just as professional. Tradify lets you create and send polished quotes, attach documents, and manage the full job workflow in one platform — making you look professional at every stage of the customer journey.
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