Finishing an Extension Properly

The last few weeks of an extension are a strange time. The big work is done, the room looks almost finished, and everyone wants to get it over the line. That is exactly when things get missed.

Finishing properly means three things: sorting out the snags, closing out the money, and getting the paperwork in place. In Scotland, that paperwork includes the completion certificate, and it matters more than people think.

Snagging: what it is and how to do it

A snag is a small defect or unfinished item: a door that catches, a scuff on the paintwork, a missing bit of sealant, a socket that is not quite level. Snagging is the process of finding them, listing them and fixing them before the job is signed off.

How to do it well:

Walk the extension with the builder, in good light, with a notepad or phone.
Go room by room, top to bottom: ceilings, walls, floors, windows, doors, fittings.
Open and close every window and door.
Test every switch, socket and tap.
Check the outside: roof edges, gutters, downpipes, drainage, external finishes.
Photograph each snag.

Agree a written snag list, with a date for completion. Then walk it again when the builder says it is done.

Most good builders welcome a thorough snag list. It is much easier to fix things before they pack up the van than to come back later.

Practical completion

Practical completion is the point at which the work is complete for practical purposes, apart from minor snags. It often triggers:

The final or near-final payment.
The start of the defects period.
The release of half of any retention, if the contract provides for it.
Responsibility for the building passing back to the homeowner, including insurance.

If your contract uses this term, it is worth being clear on the date.

The defects period

After practical completion, most contracts include a defects period, during which the builder returns to fix defects that appear. Common examples: plaster cracks as the building dries out, doors that need adjusting after the first winter, a slow leak from a fitting.

Keep a list during the defects period and send it to the builder at the agreed time, or promptly if something urgent comes up.

Retention

Retention is a small percentage of the contract value held back by the client until the end of the defects period. It is an incentive for defects to be put right. It is common on larger projects and appears in some domestic contracts.

If your contract includes retention:

Know how much it is and when it is due for release.
Release it promptly once defects are fixed.
If there are outstanding defects, agree them in writing.

Retention is not a tool to hold money back indefinitely. Used fairly, it gives both sides confidence.

The completion certificate

In Scotland, if your extension was built under a building warrant, a completion certificate must be submitted to the local authority's building standards service at the end of the work. In Edinburgh, that is the City of Edinburgh Council.

The completion certificate is a declaration that the work has been carried out in accordance with the building warrant and the building regulations. Building standards then decides whether to accept it, which may involve an inspection.

Why it matters:

It is a legal requirement for warrant work.
You need it to use or occupy the extension in some cases.
Solicitors will ask for it when you sell your house.
A missing completion certificate can delay or complicate a sale.

Who submits it? The relevant person (usually the owner or the developer) is responsible, but in practice the architect, agent or builder often prepares it. Agree who is doing it at the start of the project, ideally in the contract.

What is needed? Depending on the work and the Construction Compliance and Notification Plan issued with the warrant, building standards may want evidence such as:

Electrical installation certificates.
Drainage test results.
Energy or ventilation information.
Certificates from approved certifiers where used.
Photos of key stages.

Gathering these as you go, rather than at the end, saves weeks.

Handover pack

A good builder hands over:

Completion certificate, or evidence of submission.
Electrical certificates.
Gas and heating certificates if relevant.
Manufacturer guarantees for windows, doors, rooflights, boiler and appliances.
Operation and maintenance information for any systems.
Contact details for aftercare.

Keep all of this together. You will need it when you sell.

Final account

The final account is the last reckoning of the money: the contract sum, adjusted for variations and provisional sums. It should be clear, itemised and agreed. Once agreed and paid, apart from any retention, the financial side of the job is closed.

How we finish jobs

We walk every job with the client at completion, agree a written snag list, and come back to close it out. We prepare the paperwork for the completion certificate as we go, so it does not hold up the end of the job.

The same close-out applies to a house extension. What to put in writing before work starts is covered in what should be in your extension building contract.

FAQ

What happens if the completion certificate is not submitted? The warrant is not closed, which can cause problems when you come to sell and may be a breach of the building regulations. It is important to get it submitted and accepted.

How long is a typical defects period? It is set in the contract. Periods of six or twelve months are common on building contracts.

Can I hold back money for snags? If there are genuine outstanding snags at the end, it is reasonable to agree a sum to be paid once they are fixed. If your contract includes retention, follow its terms.

Who inspects the extension at the end? Building standards may inspect before accepting the completion certificate. Your architect may also carry out a final inspection.

What should be in my handover pack? Certificates, guarantees, manuals and the completion certificate or evidence it has been submitted.

Finishing an Extension Properly: Snagging, Retention and the Completion Certificate in Scotland