5.4 Mechanics Liens, Preliminary Notices & Stop Payment Notices

Getting paid on a construction project is a legal process with strict deadlines, and HVAC subcontractors — who are frequently paid weeks or months after finishing rough-in and startup work — rely on California's mechanics lien and notice statutes to secure payment. This section condenses the full private-works payment-security sequence: the preliminary notice, the mechanics lien itself, stop payment notices, and the statutory lien release forms.

Step 1: The 20-Day Preliminary Notice (Civil Code Sections 8200-8216)

Before an HVAC subcontractor, equipment supplier, or design professional can record a mechanics lien, file a stop payment notice, or make a bond claim on a private project, they generally must serve a Preliminary Notice — often called the '20-day notice' — on the property owner, the direct (prime) contractor, and the construction lender, if any.

• Timing: Best practice is service within 20 days of first furnishing labor or materials. A late notice is not void, but it only protects work performed in the 20 days before the notice was served and everything performed after — earlier work loses lien protection.
• Exemptions: Direct (prime) contractors do not need to notice the owner, since they already have contract privity, but must notice the construction lender if one exists under Civil Code Section 8200(e)(2). Individual wage-earning laborers are fully exempt.
• Contents: a description of the work, a good-faith total price estimate, the claimant's and hiring party's names and addresses, the jobsite address, and a mandatory boldface 'Notice to Property Owner' warning.

Step 2: Recording a Mechanics Lien (Civil Code Sections 8400-8494)

A mechanics lien is a legal claim against the property itself, recorded at the county recorder's office. Deadlines depend on whether the owner records a Notice of Completion or Notice of Cessation:

The shortened 30/60-day deadlines only apply if the owner also serves a copy of the recorded notice on claimants within 10 days under Civil Code Section 8190; otherwise the full 90-day window still applies. Once recorded, the claimant must serve a copy of the lien on the owner, and must file a foreclosure lawsuit within 90 days of recording under Civil Code Section 8460, or the lien automatically expires and becomes void.

Step 3: Stop Payment Notices (Civil Code Sections 8500-8560, 9350-9566)

A stop payment notice targets undisbursed construction funds instead of the property title. On private jobs, an HVAC subcontractor can serve a stop notice on the construction lender; an unbonded notice only asks the lender to voluntarily withhold funds, while a bonded notice, accompanied by a bond equal to 125% of the claim, legally compels the lender to withhold funds. On public works, liens are prohibited outright, since public property cannot be encumbered, so HVAC subcontractors on school, city, or state HVAC replacement contracts rely entirely on stop payment notices and payment bond claims. Under Civil Code Section 9550 (California's 'Little Miller Act'), the direct contractor on any public works contract over $25,000 must post a 100% payment bond protecting sub-tier claimants.

Step 4: Lien Releases & Waivers (Civil Code Sections 8120-8138)

California only recognizes four statutory release forms, and any custom or non-statutory waiver language is void under Civil Code Section 8122:

An HVAC contractor should never sign an unconditional release before the check actually clears the bank, and should always list unbilled retention or disputed change-order amounts in the form's exceptions field — otherwise those amounts are waived along with everything else through the release's 'through date.'

Worked Example

An HVAC subcontractor installs rooftop package units on a commercial tenant improvement job for $85,000, hired by the general contractor with a construction loan financing the project. The sub serves its Preliminary Notice on the owner, general contractor, and lender 12 days after starting work — well within the 20-day window. The general contractor pays only $50,000 and then stalls, disputing $35,000 of the work. Because the sub preserved its rights with a timely preliminary notice, it can record a mechanics lien for the $35,000 balance within 90 days of project completion, or sooner if a Notice of Completion is recorded, and can simultaneously serve a bonded stop payment notice on the construction lender to freeze $43,750 — 125% of the $35,000 claim — in undisbursed loan funds, giving the sub two independent avenues to force payment.