When a construction invoice is late or disputed, act quickly and methodically: first confirm the invoice is correct and matches the contract, then send a formal written notice, and finally escalate through the contract’s dispute resolution process if payment is still not made. This guide walks you through each step, from reviewing the invoice to protecting your lien rights, so you can get paid without burning the relationship.
Formula
The calculator above works out the net payment due on a construction invoice after retainage (a percentage held back by the client until the work is accepted). The formulas are:
- Gross amount = Work days × Daily rate
- Retainage held = Gross amount × Retainage % / 100
- Net payment due = Gross amount − Retainage held
Where Work days is the number of billable days (or hours converted to days), Daily rate is the agreed rate per day, and Retainage % is the percentage the contract says the owner may withhold. All monetary results are rounded to two decimal places.
Worked Example
Using the default values: 30 work days at $500/day with 10% retainage.
- Gross amount = 30 × 500 = $15,000.00
- Retainage held = 15,000 × 10 / 100 = $1,500.00
- Net payment due = 15,000 − 1,500 = $13,500.00
The calculator shows the same numbers: gross $15,000.00, retainage $1,500.00, net $13,500.00.
Why Invoices Get Disputed or Paid Late
Construction projects are complex, and payment problems are common. Late payments often happen because the owner or general contractor is waiting on funding, has cash flow issues, or simply processes invoices slowly. Disputes usually arise from:
- Work that the client claims was not done or was done incorrectly
- Changes or extra work that were not approved in writing
- Incomplete paperwork – missing timesheets, delivery tickets, or lien waivers
- Confusion about the contract price, unit rates, or allowances
- Damage or defects that the client attributes to your work
Understanding the likely cause helps you choose the right response. A simple delay needs a polite reminder; a real dispute needs evidence and negotiation.
First Steps: Verify and Document
Before you send any demand, check the invoice against the contract and the work performed. Make sure the amounts, dates, and descriptions are correct. If you made a mistake, correct it immediately and send a revised invoice – that often resolves the issue quickly.
Next, gather your supporting documents: signed work orders, change orders, daily logs, photos, delivery receipts, and correspondence. If the dispute is about quality, have a third-party inspector or engineer assess the work if the cost is justified. Keep a written record of every communication – emails, letters, and notes from phone calls.
How to Communicate About the Late Invoice
Start with a polite but firm written notice. Send an email or letter that states:
- The invoice number and date
- The amount due and the due date
- A request for payment by a specific date (e.g., 7 days)
- A request for an explanation if there is a dispute
Give the client a chance to explain. Sometimes the invoice was lost, or the accounting department has a different process. If you get no response, escalate to a phone call, then a certified letter. The tone should be professional – you want to preserve the relationship, but you also need to show you are serious.
When the Invoice Is Disputed
If the client says the work is defective or incomplete, do not argue immediately. Ask for specifics: what exactly is wrong, where, and what they want done. If the complaint is valid, offer to fix the problem or issue a credit. If it is not valid, explain why with evidence – photos, specs, or the contract language.
Consider a compromise if the dispute is about a small amount. The cost of litigation or arbitration often exceeds the disputed sum. A discount or a payment plan can be cheaper than fighting. But if the dispute is large, or the client is using it as an excuse not to pay, you may need to use the contract’s dispute resolution clause – usually mediation first, then arbitration or court.
Lien Rights and Legal Options
Most jurisdictions allow contractors and suppliers to file a mechanic’s lien against the property if they are not paid. A lien is a legal claim that can prevent the owner from selling or refinancing the property. The rules vary by state or country, but generally you must:
- Send a preliminary notice (in some states) before starting work
- File the lien within a strict deadline after the last day you worked or supplied materials
- Enforce the lien by filing a lawsuit within a certain period
Because deadlines are strict and the process is formal, consult a construction attorney before filing. A lien is a powerful tool, but it can backfire if you miss a deadline or make a procedural error.
Common Mistakes to Avoid
Contractors often hurt their own case by making these errors:
- Continuing to work after payment stops – this increases your exposure
- Verbally agreeing to changes without a signed change order
- Not sending a preliminary notice when required
- Waiting too long to file a lien or start legal action
- Threatening the client with a lien before you actually have the right to file
Also, do not stop work without checking your contract – some contracts forbid suspension, and stopping work could put you in breach. If you do suspend work, give written notice and state the reason.
Alternatives to Litigation
Before going to court, consider these alternatives:
- Mediation – a neutral third party helps you negotiate a settlement. It is cheaper and faster than court.
- Arbitration – a private judge makes a binding decision. Many construction contracts require it.
- Payment plans – if the client is willing but cash-strapped, a written schedule can get you paid over time.
- Factoring – you can sell the invoice to a factoring company for a fee, but this only works if the invoice is undisputed and the client is creditworthy.
These options are usually less stressful than litigation and can preserve a working relationship.
Frequently Asked Questions
How long should I wait before sending a second notice?
If the invoice is past due by more than a week, send a second notice. The first notice is often a courtesy; the second should be more formal, referencing the original invoice and the due date. Give the client a clear deadline, such as 7 days, and state what you will do if payment is not received.
Can I charge interest on a late construction invoice?
Only if your contract or state law allows it. Many contracts include an interest clause, typically 1-1.5% per month. If your contract is silent, you may not be able to charge interest unless your state’s prompt-payment laws apply. Check your contract and local regulations.
What is a mechanic’s lien and how do I file one?
A mechanic’s lien is a legal claim against the property for unpaid work or materials. To file, you must follow your state’s procedure exactly – usually filing a form with the county recorder and serving the owner. Deadlines are strict, often 90 days from last work. Consult a lawyer or the local filing office for the correct forms and deadlines.
Should I stop work if I’m not paid?
Not without checking your contract. Some contracts allow you to suspend work for non-payment, but others require you to continue and pursue payment later. If you stop work without the right, you could be in breach and lose your claim. Always send a written notice of intent to suspend if the contract allows it.
What if the client claims the work is defective?
Ask for a detailed list of defects. If the claim is valid, offer to fix the issue or issue a credit. If it is not, provide evidence – photos, specs, or third-party inspection – that the work meets the contract. If the dispute cannot be resolved, use the contract’s dispute resolution process.