A completion certificate is the form you send the council when work under a building warrant is finished, declaring that it was built as approved. The council inspects and, if satisfied, accepts it. Until it is accepted, a new extension should not be lived in.
The building warrant opens the job and the completion certificate closes it. Scotland’s system runs in that order for every extension, from a timber-frame kitchen to a module craned over the roof, and it is the second document that buyers’ solicitors ask to see.
What the certificate actually is
It is not something the council writes. It is a declaration made by the “relevant person”, normally the owner, that the work has been finished in line with the building warrant and the building standards. You send it to the council that granted the warrant, usually through the same eBuildingStandards portal used for the application, along with any certificates the warrant asked for: electrical installation, drainage tests, an energy figure, and on factory-built work, often the manufacturer’s records for the panels or modules.
The council then decides whether to accept it. Most will want a final inspection first. If the inspector is satisfied, the council accepts the certificate and records it against the property. If not, it rejects the certificate and tells you why, and you put the problems right and send it in again.
Who signs it
The owner is responsible in law, even when the builder did everything. In practice the firm or the designer who acted as your agent on the warrant usually fills in the form and gathers the paperwork, and you or they submit it. Make that part of the contract. Write in that the price includes submitting the completion certificate and dealing with the council’s final inspection, and that the last payment falls due when the council has accepted it.
When to send it
As soon as the work is finished. The certificate has to go in before the warrant expires, which is three years from the date it was granted unless you apply for more time. Our post on how long a building warrant lasts covers that deadline.
There is a second reason not to wait. A new extension should not be occupied until the completion certificate has been accepted. Councils can allow temporary occupation in some cases, but on an ordinary house extension the simple rule is to get the certificate accepted before you move the sofa in.
Why the inspections during the build matter
The warrant comes with a list of stages at which the council wants to be told work is ready to inspect, typically foundations, drainage before it is covered, and the finished job. Miss one and the inspector may ask for things to be opened up at the end, or for photographs and test results to make up for it.
On a modular extension the stages arrive quickly. The base and drains might be ready on a Monday and the room delivered on the Wednesday. Ring the council as soon as the delivery date is fixed so that someone can see the foundations before the crane arrives. Firms that build modular extensions Scotland-wide are used to this, but it is your name on the warrant, so check that the calls are made.
If a certificate was never submitted
This happens more than people expect: the builder finished, the final payment was made, and the paperwork stopped. The council still has an open warrant on its records, and a buyer’s solicitor will find it.
If the warrant is still in date, finish the process as normal. Gather the certificates, submit the completion certificate and arrange the final inspection. If the warrant has expired, ask the council whether it will extend it first; otherwise the route is a completion certificate submitted where there is no valid warrant. That route is slower and dearer. Under the fees in force from 1 April 2026, a completion certificate for work done without a warrant costs three times the normal warrant fee.
For much older work, before the current system began in May 2005, some councils will consider a letter of comfort instead.
What it costs
There is no separate fee for submitting a completion certificate for work done under a warrant. The inspection is covered by the warrant fee you paid at the start. What can cost money is the evidence: an electrician’s certificate, a drainage test, or, if a stage was missed, the time to open up a floor or wall so the inspector can see inside.
Keep a copy
Once the council has accepted the certificate, download or ask for a copy of the acceptance and keep it with the title deeds. When you sell, the buyer’s solicitor will want the warrant and the accepted completion certificate together. A few minutes of filing now saves weeks of searching later.