What is a lien waiver in construction?

Lien waivers come in four types that matter in practice. A conditional lien waiver takes effect only when a specified payment clears — it is safe to sign before the check arrives. An unconditional lien waiver takes effect immediately on signing, regardless of whether payment has been made — it should never be signed before funds are confirmed. Progress waivers cover a specific billing period; final waivers cover the entire contract and are exchanged with the last payment.

Owners and general contractors routinely require lien waivers from every tier of the project — GC, subcontractors, and material suppliers — before releasing each progress payment. This protects the owner from paying the GC and then being hit with a lien from an unpaid sub or supplier. For subcontractors, the waiver is leverage — it is the one document the owner needs to clear title — and signing it before payment is received gives that leverage away. Lien waiver requirements and enforceability vary significantly by state. This is general information, not legal advice.