Construction Lien (Mechanic's Lien): How It Works and How to Protect Your Payment

A mechanic's lien — also called a construction lien, materialman's lien, or contractor's lien — is a legal claim against a property that secures payment for labor, materials, or services provided to improve that property. It's the most powerful payment protection tool available to contractors and subcontractors, and it's often the only leverage that works when an owner refuses to pay.

Lien law is state-specific, and the rules vary significantly — deadlines, notice requirements, and enforcement procedures differ by jurisdiction. This guide covers the general framework applicable in most states, with the caveat that you should always verify your state's specific requirements before filing. When significant money is at stake, use a construction attorney.

How a Mechanic's Lien Works

A mechanic's lien attaches to the property itself — not just to the owner's bank account. Once recorded, the lien clouds the property's title, meaning the owner cannot sell or refinance without resolving the lien. This gives the lienholder leverage even against an owner who is otherwise judgment-proof or simply refuses to engage.

The process generally works like this:

1. Contractor or sub provides labor, materials, or services to improve the property
2. Owner (or GC) fails to pay
3. Contractor files a lien claim in the county where the property is located
4. Lien is recorded against the property title
5. Owner must pay, bond around, or dispute the lien to clear title
6. If unpaid within the enforcement deadline, lienholder can foreclose on the lien — forcing sale of the property to satisfy the debt

Foreclosure is rare in practice — the threat of a lien almost always produces payment negotiations. But the right to foreclose is what makes the threat credible.

Who Can File a Mechanic's Lien

Most states allow anyone who provides labor, materials, or professional services that improve real property to file a lien. This typically includes:

Preliminary Notices: The Step Most People Miss

Most states require parties without a direct contract with the owner — primarily subcontractors and suppliers — to serve a preliminary notice (also called a prelim, pre-lien notice, or notice to owner) early in the project as a condition of preserving lien rights. Miss the deadline, and you permanently lose the right to lien — even if you're clearly owed money.

The practical rule: serve a preliminary notice on every project, every time, before you start work. The cost of serving notice is trivial compared to the cost of losing lien rights.

The Lien Filing Process

Critical Deadlines by State (Samples)

Lien deadlines vary dramatically. These are general examples — verify current law in your jurisdiction:

These are general examples only. Verify current deadlines with an attorney in your state.

Public Projects: No Lien, Use a Payment Bond Claim Instead

You cannot file a mechanic's lien against government-owned property (federal, state, or municipal projects). Instead, federal law (Miller Act) and most state laws (Little Miller Acts) require GCs on public projects above a threshold to post payment bonds. Subcontractors and suppliers on public projects protect their payment by filing claims against the payment bond — not against the property.

Payment bond claim deadlines and procedures differ from lien law but are equally time-sensitive. If you're on a public project and not getting paid, you have 90 days from your last furnishing to file a Miller Act claim (federal) — miss that deadline and the claim is gone.

How Scope Documentation Protects Your Lien Rights

A mechanic's lien is only as strong as your ability to document what you did and what you're owed. Lien disputes almost always come down to: did you actually do the work you're claiming, and is your claimed amount accurate?

The documentation that wins lien claims:

• • Signed contract and change orders — establish the agreed scope and price
• • Daily reports — contemporaneous record of work performed, materials installed, and personnel on site each day
• • Delivery tickets and invoices — prove materials were delivered to the project
• • Payment applications and payment records — establish what was billed and what was paid (the unpaid balance)
• • Scope of work documents — show that the work you performed was within the contracted scope
• • Approved submittals — demonstrate that materials installed were approved for use on the project

The scope documentation that starts at plan review — understanding exactly what's in your contract before you bid — is the foundation that makes all downstream payment documentation coherent. Gaps in scope create gaps in payment claims.