Once a principal agent, engineer, or project manager signs off a contractor’s payment application, the employer is on the hook. The signed certificate stops being a request for payment that either side can still negotiate. Our courts treat it as a liquid document: a self-standing acknowledgement of a fixed debt, enforceable on the papers alone, without the contractor having to prove a single day of the underlying work.

This principle has real teeth. In 2009, the Supreme Court of Appeal confirmed in Joob Joob Investments v Stocks Mavundla Zek Joint Venture that a certificate issued by the employer’s own agent puts the employer in the same position as if it had personally signed an acknowledgement of debt. The reasoning is agency. The certifier signs on the employer’s behalf, and the employer is bound by that signature.

There is almost no defence once issued

The Constitutional Court set out the narrow list of defences available against a liquid document in Twee Jonge Gezellen v Land and Agricultural Development Bank in 2011: that the money was never advanced, that the document is tainted by illegality, or that it was obtained by fraud. Disputing the value or quality of the work is not on that list.

The Supreme Court of Appeal confirmed as much in Joob Joob, holding that a party who never actually challenged the certifier’s valuation cannot raise that dispute for the first time in enforcement proceedings. The contractor is ordinarily entitled to payment on the certificate, and the burden shifts to the employer to show why it should not have to pay.

The same principle applies against the state. In Inyatsi Construction v National Department of Public Works in 2024, the Gauteng High Court held that enforcing a final certificate is a claim for specific performance of a contractual obligation, not a “debt” under the legislation that otherwise gives an organ of state six months’ notice before it can be sued.

The certifier is an agent, not a referee

This is the point contract administrators most often get wrong. Signing a certificate binds your principal, the employer, exactly as if the employer had signed it personally. This does not licence you to certify whatever suits the employer’s cash flow. Your task is to value the work honestly, strip out defective or unmeasured work, and apply retention and any other contractual deductions before you sign.

Four habits protect the employer, and the discipline has to happen before signature.

• Value before you sign. Check the quantity surveyor’s figures, remove anything defective or unmeasured, and apply retention and contractual deductions. After signature, the money is owed.
• Keep to the contract’s timing. Late certification is one of the most common triggers of payment disputes, and can expose the employer to interest, suspension or termination claims.
• Certify within your mandate. Confirm your authority to bind the employer is recorded in your appointment, and stay within it.
• Correct through the next certificate, not by withholding payment. You cannot simply withdraw a validly issued certificate to fix a mistake. Where value is genuinely disputed, adjust it in the next certificate or refer it to adjudication under the contract.

An employer who pays certified amounts on time, and disputes value separately through the contract’s own machinery, keeps both its remedies and its standing with the contractor. An employer who tries to withhold payment on a certified amount usually loses quickly, and pays interest and costs on top of the amount it owed in the first place.

If you are an employer, contractor, or contract administrator dealing with payment certification or a construction payment dispute, contact Nikita Lalla or Ricardo Pillay for advice on your rights and obligations.

This article is general information and reflects the law at the time of writing. It is not legal advice. For advice on a specific matter, please speak to us.