A frozen, hashed snapshot of an estimate that a claim can be replayed against.
Costing and commercial control. 5 questions answered below, each with the arithmetic behind it and the limits of what the tool decides. Open the Warranty Certificate tool.
A warranty certificate records what was built, by whom, with which materials, and it does so at a moment when all of that is still known. Years later, when a defect appears, the difference between a certificate and a memory is the difference between a claim and an argument. The certificate freezes the configuration: the specification, the quantities, the products and the date. That freeze is the point, because a specification that can still be edited is not evidence of anything. A hash of the frozen configuration is stored with it, so the record can be shown to be unchanged since issue rather than merely asserted to be, which is what separates evidence from a claim.
A roof replacement with a ten year workmanship warranty: the certificate records the specification, the sheeting, the fixings, the underlay, the quantities and the completion date, then hashes the frozen set. Two years later a leak appears and the question is whether the fixings specified were the fixings used. The certificate says what was specified and that the record has not changed since. It does not prove what was installed, which is what photographs and inspection records are for.
The specification, the products and quantities, the parties, the completion date, the warranty period and its start, and a hash of that frozen set. It is a record of what was agreed and measured at handover, which is the moment when all of it is knowable. What it deliberately does not contain is an opinion, since opinions do not survive contact with a dispute. It is a short document by design: the facts that a claim turns on are few, and a record that runs to thirty pages is one nobody reads at the moment it matters.
Because a specification that can still be edited is not evidence. The value of a certificate is that it records a state at a date and can be shown not to have changed since. Freezing the configuration is what allows the hash to mean anything: a hash of something revisable proves only that the revision happened.
That the recorded configuration is the one that was issued, unchanged. It is a check on the record, not on the building. If a specification is altered after issue, the hash no longer matches and the alteration is visible. What it cannot tell you is whether the work on site followed the specification, which requires inspection records.
No. It is a record, and a record is what a warranty claim is argued with rather than what creates the warranty. The warranty itself comes from the contract, the guarantee or the statute. The certificate's job is to make the facts of the work available years later, in a form that can be trusted, which is often the difference between a claim that proceeds and one that stalls.
At practical completion, or at the completion of the element it covers. Issuing it later means reconstructing the specification from memory and photographs, which is exactly the situation the certificate exists to avoid. Where an element is completed early, such as a roof before the interior is finished, that element can be certified on its own date.