Millwork has a structural cash flow problem, and most subcontracts make it worse. Material is purchased and shop labour is spent months before anything reaches site — but billing is usually tied to installation, and millwork is one of the last trades in. The result is the longest gap between spend and payment of any trade on the job.

Billing for stored materials and off-site fabrication is the mechanism that closes that gap. It only works if it’s in the contract.

Why millwork is different

Most trades spend as they install. Millwork doesn’t:

• Materials bought early — panels, veneer, hardware and solid surface procured at the start, often a reserved flitch that must be secured before anyone else can claim it
• Shop labour spent early — engineering, machining, assembly and finishing all happen before delivery
• Delivery late — millwork goes in near the end, after the space is closed and finished
• Holdback released last — being last on site means the longest tail on the final payment

A package can be 80% complete in the shop and 0% billable under a subcontract that only recognises installed work.

Off-site fabrication and stored materials

Two related but distinct claims:

• Stored materials — raw goods purchased and held for the project (panels, hardware, reserved veneer)
• Off-site fabricated work — completed millwork sitting in the shop or in storage awaiting a site date

Both are commonly billable, but only if the subcontract says so. Silence usually defaults to installed-work-only.

What owners and GCs will want before paying

• Supplier invoices establishing the cost claimed
• Segregation and identification — material physically set aside and marked to the project, not sitting in general inventory
• Photographs, and sometimes a physical inspection
• Proof of insurance covering the material while stored
• Bill of sale or transfer of title in some contracts, so the owner holds title to what they’ve paid for

These are reasonable protections. A fabricator who can produce them quickly gets paid; one who can’t, argues.

Negotiate this into the subcontract — not after

The time to secure stored-materials billing is when the subcontract is being signed, alongside scope and schedule. Points worth settling:

• That off-site fabricated work and stored materials are billable, and at what percentage
• What documentation is required, agreed up front rather than invented at the first application
• Who insures stored material, and to what value
• Whether material must be stored at a bonded or third-party facility, or whether the fabricator’s own plant qualifies
• How storage is handled if the site date slips — which on millwork it frequently does, and storage isn’t free

This is worth more to a millwork subcontractor than almost anything else in the commercial terms. Prompt-payment legislation only accelerates payment on a proper invoice — it does nothing if the right to bill off-site work was never in the contract.

What a GC gets out of it

It isn’t one-sided. A subcontractor who can bill progressively is a subcontractor who can buy materials early, lock a flitch or specialty material before it’s gone, and keep the shop moving during a site delay. Starving the millwork trade of cash flow is one of the more reliable ways to end up with a schedule problem — and a defaulted millwork package is uniquely hard to replace, because shop drawings, templates and matched veneer aren’t fungible.

Frequently asked questions

Can a millwork subcontractor bill for stored materials?

Yes, if the subcontract permits it. Billing for off-site stored materials or completed off-site fabrication is common on millwork packages, but must be written into the contract — typically supported by invoices, proof of insurance, and sometimes a bill of sale or inspection.

Why does millwork have a cash flow problem on construction projects?

Costs are front-loaded — materials and shop labour are spent months before delivery — while billing is usually tied to installation, and millwork is one of the last trades on site.

What documentation supports a stored materials claim?

Supplier invoices, photographs, evidence the material is segregated and identified to the project, proof of insurance, and in some cases a bill of sale transferring title or a physical inspection.

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