Legal

What is a mechanics lien in construction?

A mechanics lien is a legal claim an unpaid contractor, subcontractor, or supplier records against the property it improved, which can force payment because the owner cannot sell or refinance cleanly until it is resolved.

An office manager and contractor review invoices with a calculator and laptop in a construction office.
Review invoices, committed costs, and cash timing together before making project decisions. AI-generated illustration.

A mechanics lien (also called a construction lien or, in some states, a materialman's lien) is a security interest in real property, created by state law, for people who added value to that property and were not paid. If a drywall sub hangs board in a building and the GC never pays, the sub can record a lien against the building itself. The lien attaches even though the sub never had a contract with the owner.

That is what makes it powerful. The owner may have already paid the GC in full and still face a lien from the GC's unpaid sub. In the worst case, a court can order the property sold to satisfy the claim.

How a mechanics lien works

Every state writes its own lien law, but the steps follow a similar pattern.

  1. Notice. Many states require a preliminary notice or notice to owner early in the job, especially from subs and suppliers who do not contract with the owner. Miss it and the lien right may be lost before any money is late.
  2. Recording. If payment does not come, the claimant records a claim of lien with the county recorder within a deadline that usually runs from completion of the project or the claimant's last work.
  3. Enforcement. The claimant has a limited time to file a lawsuit to foreclose the lien. If it does not, the lien typically expires.
  4. Resolution. The claim is paid and a lien release is recorded, a bond replaces the lien, or a court rules on it.

California as an example of the deadlines

The deadlines are short and strict, and they vary by state. California shows how they stack up:

California private work recording and enforcement deadlines
ClaimantRecord the lien before the earlier ofThen sue to enforce within
Direct contractor (Civil Code 8412)90 days after completion, or 60 days after the owner records a notice of completion or cessation90 days after recording (Civil Code 8460)
Sub, supplier, or other claimant (Civil Code 8414)90 days after completion, or 30 days after the owner records a notice of completion or cessation (and only after it stops work)90 days after recording (Civil Code 8460)

Notice how a recorded notice of completion can cut a sub's window to 30 days. Other states use different clocks entirely. Check your state on the mechanics lien laws by state page.

An example on a real job

Say a concrete sub pours footings and slab on a $3.4 million private medical office. It sent its preliminary notice in week two. The GC pays the first two pay apps, then stops, citing cash flow, with $61,000 unpaid. The sub's lien deadline is running the whole time it is sending polite reminder emails.

Sixty days later the sub records a lien for $61,000. The owner's lender sees it on the next title check and holds the draw. Now the owner and GC both want it gone, and the sub gets paid within a few weeks in exchange for a recorded release. The lien did not require a lawsuit. It just moved the sub's invoice to the front of the line.

Common mistakes and disputes

  • Skipping the preliminary notice because the GC is a long-time customer.
  • Counting from the wrong date. Last day of work, completion of the whole project, and recorded notice of completion are different triggers.
  • Overstating the claim. Adding unapproved extras, interest, or work not yet done can expose the claimant to penalties in many states.
  • Signing waivers too early, such as an unconditional lien waiver before the check clears, which can give the right away.
  • Trying to lien public property. Public jobs usually cannot be liened. Payment bonds under the federal Miller Act or state equivalents take their place; see payment bond.

Related terms

See notice of intent to lien, lien priority, notice of commencement, and retainage, which is often the last money on a job and the most likely to need lien protection. The guide when to file a mechanics lien covers the decision. Smart Business Automator tracks notice dates and outstanding balances by job in construction accounts receivable automation, so lien deadlines are visible before they pass.

Frequently asked questions

Who can file a mechanics lien?

Generally anyone who furnished labor, materials, or certain services to improve private property and was not paid, including GCs, subs, suppliers, and sometimes equipment renters and design professionals. Each state defines eligible claimants differently.

How long does a mechanics lien last?

Not forever. The claimant must file a lawsuit to enforce it within a state deadline, or the lien expires. In California that window is 90 days after recording, unless the parties record an extension of credit.

Can a lien be filed if the owner already paid the GC?

In many states, yes. That is why owners collect lien waivers from subs and suppliers before paying, and why some states require preliminary notices so owners know who is on the job.

Is a mechanics lien the same as a judgment?

No. A mechanics lien attaches to the specific property improved and comes from state lien law. A judgment comes from a lawsuit and can attach to the debtor's property generally.

Sources

  1. California Civil Code section 8412, direct contractor lien deadline (public.law)
  2. California Civil Code section 8414, other claimant lien deadline (public.law)
  3. California Civil Code section 8460, time to enforce a lien (public.law)
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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