Construction retention tracking in Belgium: keep invoices and guarantees distinct

Name the mechanism before tracking the amount

Construction teams use “retention” for different arrangements: an amount withheld from an invoice, a contractual guarantee, a public-procurement bond or a guarantee under specific housing rules. These mechanisms do not share one universal percentage or release date. The contract and applicable legal framework decide what the parties must do.

Belgian official information illustrates why the label matters. The FPS Finance page on building and the Breyne Law describes a specific housing guarantee and staged release around provisional and final acceptance. BOSA describes separate rules for guarantees in public procurement. Do not copy those figures into a private B2B project unless that regime actually applies.

Create a retention record next to the invoice

Keep the commercial invoice intact and record the retained amount separately. The record should identify:

• project and customer;
• contract clause or procurement document;
• related invoice and billing period;
• gross certified amount;
• amount currently retained;
• reason for the retention;
• release condition;
• expected review date;
• evidence required;
• owner and current status.

This avoids a common reporting error: showing the whole invoice as overdue when the customer paid the undisputed amount and a contractually identified part remains retained.

Link release to evidence, not memory

Release may depend on provisional acceptance, correction of defects, final acceptance, expiry of a guarantee period or a formal request. Convert the contract wording into a project checkpoint and attach the relevant evidence: acceptance report, completed punch list, customer confirmation or formal release document.

Do not assume that finishing physical work automatically releases every amount. The administrative condition may still be open. Equally, do not leave a retained amount hidden after all conditions are satisfied. Give one person responsibility for checking the release date and sending the required request.

Reconcile project, receivables and cash forecast

Show three figures separately: work invoiced, cash received and retention still outstanding. The project margin should not treat retention as a new cost, while the cash forecast should not count it as available money before release is reasonably expected.

If the customer disputes more than the agreed retained amount, create a separate dispute record. Capture the claimed defect, responsible person, response deadline and financial impact. Mixing a commercial dispute with contractual retention makes collection and project close-out harder to manage.

Review tax and correction questions

A retained payment does not automatically change the issued invoice or its VAT treatment. If the invoice amount itself must change, ask the accountant whether a credit note or other correction is required. Keep the original invoice, payment allocation and any correction linked.

For public works or protected housing projects, verify the current official rules and contract documents. This article describes an operational record, not a conclusion about which legal regime applies to a particular project.

Close only when the balance is explained

At project close-out, every retained amount should be released, actively disputed or supported by a future dated condition. Reconcile the customer ledger to the project record and keep the release evidence with the acceptance documents.

Connect the process with construction progress billing and the digital handover workflow. To track project, invoice and follow-up context together, explore Enfin.