MW Builders, a general contractor, tried to recover money on behalf of its subcontractor Bergelectric by claiming the subcontractor's lien waiver didn't apply to all claims. The federal court rejected this argument, ruling that when a subcontractor signs a clear lien waiver covering a specific time period, it gives up all claims from that period—no exceptions. The court also said it cannot rewrite private contracts between contractors and subcontractors. This means subcontractors need to be extremely careful about what they waive in writing.
A signed lien waiver with clear language and dates will be enforced as written. Courts will not let contractors argue around it on your behalf.
Once you sign a lien waiver releasing claims through a certain date, you cannot later claim you were owed money for work done before that date.