You are sitting at the kitchen table looking at a job you finished six weeks ago and an invoice the homeowner is now picking apart. The problem started long before they stopped paying. It started with the contract you signed (or the one you never wrote down). A good contract will not make every client pay on time, but it gives you the tools to collect when they don't.
Why the Contract Decides Whether You Get Paid
When a client stops paying, the contract is the first thing a judge, a mediator, or your own demand letter will reference. Vague terms favor the client. Specific terms favor you.
If your agreement was a text thread and a verbal "we're good," collecting is hard. If it was a signed document with payment dates, late fees, and a scope locked down in writing, you have leverage. The same logic applies whether you write a formal demand letter or end up in small claims court.
Write Payment Terms That Leave No Room to Argue
Most disputes start because payment expectations were never written clearly. Spell out exactly when money is due and what counts as late.
- Deposit: 25% to 50% due before work starts, non-refundable once materials are ordered
- Progress payments: tied to specific milestones (rough-in complete, drywall up), not vague percentages
- Final payment: due within 7 days of substantial completion, not "upon satisfaction"
- Accepted payment methods: list them, and exclude anything you won't take (personal checks over $5,000, for example)
- Late fee: 1.5% per month on unpaid balances, applied after a 10-day grace period
Avoid "upon satisfaction" or "when the client is happy." That language makes payment subjective. Tie payment to objective events: dates, inspections, or specific completed work.
Lock Down the Scope and Force Change Orders in Writing
A vague scope is the second most common reason invoices get disputed. The client says the new bathroom included the vanity. You say it didn't. Without a written scope, that argument has no winner.
Your contract should list what's included in plain language, what's excluded, and what materials are specified. Then add a change order clause: any work beyond the original scope requires a written change order signed before the work starts. No exceptions.
Sample clause: "Any modifications to the scope of work, including additional materials or labor, require a written change order signed by both parties before the additional work begins. Verbal changes are not binding."
That single paragraph kills 80% of "I never agreed to that" disputes before they start.
Add Clauses That Make Non-Payment Expensive
These are the clauses that turn a contract from a handshake into a tool. Every one of them changes what a client risks by withholding payment.
- Late fees and interest: 1.5% per month is standard and enforceable in most states
- Stop-work clause: you reserve the right to suspend work if a progress payment is more than 10 days late
- Attorney's fees and collection costs: if you have to pursue collection, the client pays reasonable costs
- Venue clause: disputes are resolved in the county where the work was performed
- Acceptance clause: if the client does not object in writing within 7 days of completion, the work is deemed accepted
Lien rights are a separate remedy that varies significantly by state. If you want to preserve them, talk to a licensed attorney in your state about the specific notice language and deadlines. Do not rely on a generic clause copied from the internet.
Build Documentation Requirements Into the Contract
The contract is also where you set expectations for how the job will be documented. This protects you twice: it forces the client to engage on the record, and it gives you evidence if things go sideways.
- Photos before, during, and after each phase, shared with the client by email
- Sign-off on milestone completion before the next progress payment is invoiced
- All communications about changes, delays, or issues in writing (email or text)
- A final walkthrough with a written punch list, dated and signed
When a client later disputes the work, this paper trail is the difference between a quick resolution and an expensive fight. Our guide on handling invoice disputes after the job walks through how to use this documentation when the fight actually starts.
What to Do When the Contract Still Doesn't Get You Paid
Even a strong contract won't stop every bad client. Some people just won't pay. The contract's real job is to make the next step easier: a written demand that references specific contract terms the client agreed to.
Writing that letter is where most contractors get stuck. The tone has to be firm without being emotional, the legal references have to be accurate, and the deadlines have to be realistic. PaperHammer generates three escalating versions (polite, firm, final demand) referencing your state's small claims limit, in about five minutes. You fill in the job details and the contract terms you set, and you get back letters you can send the same day.