Since 1 January 2026, Belgian VAT-registered businesses send and receive their business-to-business invoices in a structured electronic format, via the Peppol network. We explained the general principle in an earlier article. But a construction contractor does not invoice like a shop: reverse charge, deposits, progress billing, credit notes, invoices to private individuals and to public bodies. Each of these situations has its counterpart in a Peppol invoice, and site management software that ignores it produces invoices that are rejected or, worse, accepted but wrong.
Reverse charge: a code, and a notice
For construction work invoiced to another VAT-registered contractor, VAT is payable by the client, the co-contractor: this is the reverse charge provided for by Article 20 of Royal Decree No. 1. In a Peppol invoice, this translates into a specific VAT category code. The reference document published by the administration in February 2026 gives the code AE for this work, to be completed with the reason “Autoliquidation” at line level and a note at invoice level.
This note carries the usual wording: absent a written objection within a month, the client is deemed to acknowledge being a VAT-registered business required to file periodic returns. The administration specifies that a client cannot refuse an invoice missing this full clause, as long as the words “autoliquidation” or “TVA autoliquidée” appear. But the supplier then bears the consequence: without the clause, the transfer of liability does not work in its favour. A single invoice may also combine several VAT codes, for instance one part under reverse charge and one at the standard rate.
The 6% renovation rate, often outside Peppol
The reduced 6% rate for renovating a home over ten years old applies to work invoiced to the end consumer, owner, tenant or usufructuary, for a home used mainly privately. Since July 2022, there is no longer a certificate: the invoice itself must state the elements justifying the reduced rate. Yet invoices addressed to private individuals are not subject to the Peppol obligation. A good share of renovation therefore stays outside the network, and your software must handle both: Peppol for businesses, a conventional invoice with the right wording for individuals.
Watch out for recent changes too. Since 29 July 2025, installing fossil-fuel heating during a renovation is invoiced at 21%, and the transitional measure for earlier contracts ended on 30 June 2026. The FPS Finance accepts a flat-rate split for a hybrid system sold at an overall price: 35% at the 21% rate and 65% at 6%. A rate hard-coded into software is exactly the kind of rule that eventually makes it wrong.
Deposits and progress billing
A building project is rarely invoiced in one go. The Peppol format provides a document type for the deposit invoice, code 386, defined as an invoice for amounts paid in advance that will be deducted from the final invoice. On the final invoice, a dedicated field shows the amount already paid, which the format subtracts from the total to give the balance due. If your software simply adds a negative “deposit already paid” line, the invoice may pass validation while being misread by your client’s accounting software.
For progress billing, the list of accepted codes even includes three construction-specific codes: partial construction invoice, partial final invoice and final construction invoice. But the Peppol specification states that the partial and final invoicing process is outside its scope, and we found no official Belgian guidance on their use. In practice, before using them, check with your access point and main clients that their software handles them. Your detailed progress statement or bill of quantities can accompany the invoice as an attachment, as a PDF or spreadsheet: the administration points out that attachments are legally part of the invoice and must travel through the same channel.
A construction invoice is not like any other. If your software treats it as one, your client will be the one to notice.
Credit notes and public contracts
Credit notes follow the same route: between businesses, they too must go through Peppol, with their own document type. The only tolerated exception: a credit note issued in 2026 to correct a 2025 paper or PDF invoice may stay in the same format as the original invoice. Another constraint of the current standard: an invoice can only reference a single purchase order; the administration has published a temporary workaround for cases that combine several.
For contractors who work with public bodies, the obligation is older: since March 2024, invoices over 3,000 euros under certain public contracts must be electronic. The free Mercurius portal lets you enter them by hand, but only for public administrations, not to invoice other businesses. To find out whether a client is a contracting authority, the Crossroads Bank for Enterprises shows it among its “qualities”.
The grace period is over, 2028 is coming
The general grace period ended with the first quarter of 2026. According to the FPS Finance as quoted in the press, nearly nine in ten VAT-registered businesses were using Peppol by mid-July. Fines are set by law, from €1,500 for a first offence up to €5,000 for repeat offences. On the incentive side, SMEs and the self-employed can deduct 120% of their e-invoicing subscriptions and related consultancy fees up to the 2027 tax period.
What comes next is announced: the administration plans e-reporting for 2028, the transmission of invoice data to the tax authority, which will replace the annual client listing; the measure still has to be transposed into Belgian law. In practice, the data in your construction invoices will be read by one more machine. A wrongly chosen VAT code or a badly deducted deposit will no longer remain an approximation between you and your accountant.
What your software needs to handle
- Choose the right VAT code per line, including reverse charge with its full notice
- Tell clients apart: Peppol for businesses, a conventional invoice for individuals, a dedicated channel for public bodies
- Handle deposits and balances with the intended document type and field, not with negative lines
- Attach site documents to the electronic invoice
- Receive invoices from your suppliers and subcontractors, because the obligation works both ways
Off-the-shelf invoicing software covers some of these cases. When your invoices originate in site management software built for you, that is what has to produce these files, and that is exactly the kind of integration we carry out in product engineering. Show us one of your construction invoices: we will tell you what is missing for it to go cleanly through Peppol, today and in 2028. For a specific tax question, your accountant remains the right person.