Signed Quote With No Start Date in Belgium: What Are Your Rights?

Key Takeaway: In Belgium, omitting a start date does not invalidate a quote: once signed, it remains a legally binding contract. The mere passage of time does not automatically place the contractor in default; the client must first send a written reminder followed by a formal notice setting a reasonable deadline.

You've signed a quote, but it doesn't list a start date for the work. Good news: that's not an irregularity. Under Belgian law, the start date isn't one of the mandatory details on a quote. The quote is still valid, and becomes a contract as soon as the client signs it, whether or not a start date is written on it.

That doesn't mean the missing date causes no practical friction. It's actually one of the most common sources of disputes between a client and a contractor.

1. The start date isn't mandatory, and that's by design

A Belgian quote needs a precise set of details: the identity of both parties, a VAT or company number, an itemised breakdown of the service, the applicable VAT rate, a validity period for the offer. You'll find the full list in our guide on writing a professional quote in Belgium. The start date isn't part of that list, for a simple reason: at the moment of signing, a contractor doesn't always know their exact schedule. A previous job can run late, a materials delivery can slip by a week. Requiring a firm date at quote stage would make a trade that deals, by nature, with the unexpected far too rigid.

2. A signed quote remains a contract, with or without a start date

This is the central point, and plenty of clients (and contractors) get it wrong. As soon as the client signs with the words "approved" or "bon pour accord," the quote becomes a mutual contractual commitment: the contractor commits to carrying out the described work at the agreed price, the client commits to paying it. A missing start date doesn't undo that commitment. It only leaves a grey area on one specific point: from when can you actually call it a delay?

3. Why the mere passing of time doesn't put the contractor at fault

This is where Belgian obligations law settles the question, and the principle often surprises people: the mere lapse of a deadline, even one mentioned somewhere, never automatically puts the debtor (here, the contractor) in default. Unless the quote states otherwise, the creditor (the client) needs to send a formal notice before the delay starts counting legally. That's what Book 5 of the Belgian Civil Code sets out, in force since 1 January 2023, in its chapter dedicated to formal notice (articles 5.231 to 5.233).

In practice, if no start date appears on the quote, the client can't simply wake up one morning and decide, on their own, that the contractor is at fault because three months have gone by. They first have to formally request that the contract be carried out.

Personally, I find this mechanism fairly sound in both directions: it protects the contractor from a client who changes their mind midway and invents a fictional delay as an excuse to back out, and it protects the client from a contractor who keeps pushing things back without ever being formally called to order. It does assume the client knows they have to act, which, in practice, is almost never the case.

4. What to actually do if the work still hasn't started

1. Send a simple written message first. An email is enough: "The quote signed on [date] doesn't mention a start date, could you confirm an expected date?" Most situations get resolved at this stage, with no formal procedure needed.
2. If the silence continues, move to a written formal notice, ideally by registered letter with acknowledgement of receipt. It should reference the signed quote, note the lack of execution, and set a new, feasible and therefore reasonable deadline to start (Belgium's SPF Économie states this explicitly for this kind of construction dispute).
3. If that new deadline passes with no response, you have recourse: forced performance, termination of the contract, or damages depending on the actual harm suffered.

No official text sets a universal number of days beyond which a "reasonable timeframe" is automatically exceeded: it depends on the nature of the job, installing a water heater doesn't run on the same schedule as a full roof replacement. Be wary of figures thrown around on forums as if they were a fixed legal rule: they aren't.

If your dispute is about an unpaid invoice rather than a delayed start, the formal notice procedure is covered step by step in our guide on formal notice for unpaid invoices.

Download formal notice Word template, Belgium

5. For contractors: how to avoid this dispute when writing the quote

Tip: To avoid locking yourself into an unrealistic fixed date while reassuring your client, state on your quote: "Work estimated to start within 3 to 5 weeks following receipt of the 30% deposit and administrative clearance."

Leaving it blank isn't a mistake, but it isn't the best sales strategy either. A client who doesn't know when their work is starting is a client who doubts, follows up, and sometimes turns to a competitor who was more precise. Two simple habits cut the risk of a dispute, without committing you legally more than necessary:

• State an expected start date, explicitly framed as such ("subject to availability, expected start in [month]") rather than a firm date you don't fully control.
• Set a clear validity period for the offer (typically 30 to 60 days), so the client understands the quote commits to an overall timeframe, even if the exact starting point still needs confirming.

How HeyDevis reduces this kind of ambiguity

A quote created on HeyDevis carries a timestamped signature date and an event history (sent, viewed, signed) tied to each quote. If there's a disagreement about when the commitment actually started, that precise record, rather than a rough memory on either side, is what settles it. The service catalogue also lets you itemise every line of the quote, which narrows down what was actually agreed on.

What HeyDevis doesn't do: guess your site schedule for you. Stating a realistic start date stays your call; the tool just makes everything around it more reliable (numbering, legal mentions, signature, proof).