Spray foam installation certificates: do they help?

Installers differ in what they hand over, so there is no single standard sheet. A typical certificate or guarantee names the company, the address, the date, the type of foam and the area covered. Some add a product data sheet and a warranty from the foam manufacturer.

Those details are useful for a plain reason. A surveyor who has flagged foam wants to know which product it is, open-cell or closed-cell, how thick it was applied and whether anyone checked the roof before it went on. Our guide to adding ventilation instead of removal shows why the answer to those questions shapes what can be done next.

A certificate also tells you who to contact. If the installer still trades, you can ask them for their records and for the paperwork that supported the installation. If they have closed, the certificate is at least a trail to follow.

What it cannot do is describe the present condition of the roof. It is a record of the day the work was done.

Requests vary by lender and by surveyor, so ask for the list rather than guess. The documents that tend to come up fall into three groups.

• Who installed it and what product: the certificate, the guarantee and the data sheet.
• Whether the risk was assessed first: the RICS consumer guide expects thermal and condensation checks from a qualified person before foam goes in, so a copy of that work answers the question directly.
• What the roof looks like now: a specialist assessment, moisture readings from the timbers and dated photographs.

The third group is usually the one that moves a file. Our page on spray foam and mortgages covers why lenders differ, and the pattern is that a certificate alone seldom settles it for a cautious lender. A lender that reviews cases one at a time is more likely to respond to a complete file than to a single sheet.

Check dates as well as names. A certificate issued years ago says nothing about the roof today, so a lender or surveyor may well want something recent beside it. An inspection report dated within the last few months, tied to photographs of the same roof, makes the older certificate easier to rely on, because the two documents describe one roof at two points in time.

Many owners inherit foam with nothing in the deeds. The previous owner may have used an installer who has since closed, or may have done a scheme through a grant, or the work may simply predate the sale. Missing paperwork is a problem, but it leaves the file short, not beyond repair.

Without a certificate, evidence of condition carries more weight. An inspection that opens a small section, reads the moisture in the timber and photographs the back of the covering hands the surveyor something concrete to assess. We record what the foam is, how far it extends and what the exposed timber looks like, then set that out in photographs from your roof and a written note.

Ask the seller or previous owner to check any papers from the time, including emails, invoices, warranty cards and even bank statements that show who was paid. Ask your solicitor how a missing certificate should be handled, as we do not give legal or insurance advice.

Certificates matter more where inspection is hard. Foam inside a flat-roofed extension or the side wall of a dormer is difficult to see, because the timbers sit between a deck and a ceiling with no loft space to look into. In those places the installer's record may be the only evidence of what was sprayed and how deep.

That is also why a surveyor may want an opening cut rather than rely on paperwork. Our answer on spray foam on flat roofs and dormers explains how those assessments differ from a pitched-roof loft check.

If you do have a certificate for a flat-roof installation, keep it with the build-up details. The type of deck, the vapour control layer and the ventilation, where there is any, all affect how the foam behaves, and a certificate that mentions them is worth more than one that gives only an address and a date.

The most helpful thing is to assemble one folder in date order. Put the certificate and guarantee first, then any calculation, then the inspection report, moisture readings and photographs. Add the lender's or surveyor's own wording about what they need.

If work follows, it joins the folder. Once the roof has been surveyed we write one quote for the job, photograph the finished work for your folder and give a ten-year workmanship guarantee on paper. If the job is notifiable, the Building Regulations paperwork is ours to deal with.

MyBuilder's 2026 figures for a spray foam assessment sit between £100 and £200, a modest sum against a stalled sale. Post or email whatever papers you hold, with some loft or roof-edge photographs, and we will list what the file lacks and what an inspection would add. The full service is described on our spray foam insulation removal page.