Subcontractor Back-Charges: How to Document, Apply, and Collect Them
A back-charge is a cost the GC incurs because of a subcontractor's action or failure that gets charged back against the sub's contract. The sub breaks a window; the GC pays to replace it and back-charges the sub. A sub leaves the site dirty; the GC pays for cleanup and back-charges. A sub doesn't complete their punch list; the GC hires another trade to finish and back-charges.
Back-charges are a normal tool in GC-sub contract management. Subcontracts explicitly authorize them, and most prudent GCs apply them when subs cost money. What separates enforceable back-charges from disputable ones is documentation. A well-documented back-charge with clear cause, dollar amount, and paper trail is rarely disputed. A poorly-documented one gets pushed back on and often reversed.
Typical back-charge scenarios:
Common back-charge situations
- Damage to other trades' work — a sub damages another trade's installation, and the GC pays to repair the damage
- Site cleanup — a sub leaves debris or the GC has to clean up after the sub has demobilized
- Failure to complete punch list — a sub doesn't return for punch work, and the GC hires a completion trade
- Safety violations causing project delay or remediation cost — a sub's unsafe practice triggers an OSHA incident or required training that costs the project
- Protection failures — a sub failed to protect their work or adjacent trades' work, resulting in damage
- Rework of defective work — a sub's installation fails inspection and requires redoing; direct costs can sometimes be back-charged even if the sub's own rework is their own cost
- Cost of managing the sub's failures — supervision time the GC incurred beyond normal for managing a problem sub
- Overtime or acceleration costs attributable to the sub's delay
Subcontracts typically authorize back-charges explicitly — the sub agrees in the subcontract that costs arising from their defaults are chargeable against their contract balance. The specific authorization is usually in the General Conditions portion of the subcontract.
A defensible back-charge has several layers of documentation:
Documentation for an enforceable back-charge
- Incident description — what happened, when, where, which party caused it
- Photos or video — contemporaneous images of the damage or condition
- Daily report entries — the superintendent's daily log should capture the incident on the day it occurred
- Notification to the sub — written notice to the sub that a back-charge is being incurred, giving them the chance to address it themselves before the GC does
- Cost documentation — invoices, timesheets, material receipts for the cost being back-charged
- Allocation explanation — if the back-charge includes markup (for GC supervision, overhead), how it's calculated
- Sub acknowledgment (if obtained) — ideally the sub agrees; if not, the sub's objection and the GC's response
The notification-before-action step matters. A GC that incurs a back-charge cost without first giving the sub a chance to address the issue is on weaker ground. The subcontract typically requires notice, and courts enforce the notice requirement. Back-charges that skip the notice step are vulnerable to being reduced or disallowed.
Notify the sub in writing before back-charging. Even a same-day email saying "we're having to pull workers off the critical path to clean up your demo debris; we'll be back-charging you for this time unless you address it by end of shift" creates the paper trail that supports the back-charge later.
The back-charge amount should be the actual cost incurred, not an inflated number. Components typically include:
What to include in the back-charge calculation
- Direct labor — timesheets for GC or third-party labor addressing the issue
- Direct materials — receipts for materials purchased to address the issue
- Equipment — time on equipment used, at internal rates or rental rates
- Sub-sub costs — if the GC hired another sub to do the work, their invoice
- Supervision — GC's project management time allocable to managing the issue, at a reasonable rate
- Markup — GC overhead and profit on the back-charged cost, per the subcontract's markup provision
The markup piece is often where disputes arise. Subcontracts typically allow the GC a markup on back-charged costs (to cover overhead and profit on managing the situation). Common markups are 10-15%. Higher markups, or disputed overhead rates, are where subs push back. Transparent markup calculations tied to the contract provision make the back-charge easier to defend.
A back-charge is typically applied by reducing the amount paid on the sub's next pay application or by reducing retention at closeout. The sub's gross earned amount stays the same; the payable is reduced by the back-charge amount. Specifically:
Mechanics of applying a back-charge
- Document the back-charge with all supporting evidence
- Notify the sub in writing with the specific amount and the basis
- Record the back-charge as a separate line item on the sub's AP ledger
- Reduce the next pay application payment by the back-charge amount, showing the deduction explicitly on the pay app summary
- If the sub's next pay app is insufficient to cover the back-charge, reduce subsequent pay apps or retention release
- Maintain the back-charge file as part of the sub's ledger so any later dispute has complete documentation
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Disputed Back-Charges
Subs dispute back-charges in a few common ways. They may argue the incident wasn't their fault (the damage was caused by a different trade). They may argue the cost charged is inflated beyond the actual cost. They may argue the notice wasn't given properly. Or they may argue the GC's supervision or markup rates are excessive.
When a dispute arises, the GC's documentation is the decisive factor. Complete incident logs, photos, daily reports, notification emails, and itemized cost backup usually resolve disputes in the GC's favor. Thin documentation leads to reduction or reversal of the back-charge as a negotiated settlement.
Back-charges can be applied against retention at closeout, but timing matters. Retention release typically requires a final unconditional lien waiver from the sub. When a back-charge reduces the retention payment, the lien waiver amount should match the net amount paid, not the gross retention before back-charge. A sub who signs a full-retention lien waiver and then finds the retention reduced by a back-charge has waived lien rights for consideration they didn't fully receive — a setup for future dispute.
The clean practice: calculate the net amount to be paid (retention minus back-charges), communicate it to the sub with the back-charge documentation, obtain the sub's signed acknowledgment of the net, and issue a lien waiver for the net amount paid.
Mistakes that weaken back-charge enforceability
- No written notice to the sub before incurring the cost
- Thin or missing documentation of the underlying incident
- Supervision time not properly tracked — vague "project management time" without specific hours
- Markup applied above what the subcontract authorizes
- Back-charge applied without allocating it against the right sub (charging the wrong sub for damage caused by another)
- Cumulative back-charges that exceed the sub's remaining contract balance without clear accounting
- Lien waivers signed for gross amounts without back-charges being netted
Modern construction AP systems handle back-charges as a specific transaction type linked to the sub's contract. Each back-charge gets a unique number, documentation attachments, a dollar amount, a status (proposed, notified, applied, disputed, resolved), and an automatic application against the sub's next pay application.
For subcontractors on the receiving end, the AP system's back-charge trail gives them something to review and dispute through proper channels. The transparency usually reduces disputes — a sub who sees the specific incident, cost, and documentation is more likely to agree than one who just gets a smaller check than expected with no explanation.
Back-charges are a legitimate tool for allocating costs that subs cause back to the responsible party. Done with proper notice, complete documentation, reasonable markups, and transparent accounting, they resolve quickly and keep projects fair. Done sloppily, they become long-running disputes that eat up retention and delay closeout. The difference is mostly about documentation discipline — daily reports that capture incidents, written notice to subs, itemized cost calculations, and clean AP records that show the back-charge trail.
Written by
Marcus Reyes
Construction Industry Lead
Spent twelve years running AP at a $120M general contractor before joining Covinly. Lives in the world of AIA G702/G703, retainage schedules, and lien waiver deadlines. Writes about the construction-specific workflows that generic AP tools get wrong.
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