Surveyors, solicitors and lenders all refer to the RICS when spray foam turns up in a roof. The Royal Institution of Chartered Surveyors put out a householder-facing document on spray foam in March 2023, and Mortgage Solutions covered it on 3 March. Because the guide is written for householders, it uses plain language and runs to a few pages. That brevity is why it gets quoted loosely, so reading it for yourself is worthwhile.
This guide sets out its main points, then explains how to read them: as a set of questions to put to whoever installed the foam, to your surveyor and to the companies you pay. It is about the document. Whether removal is always needed is a different question, and our answer on whether spray foam must be removed settles it. The wider service is described at spray foam insulation assessment and removal. You can read the source itself on the RICS website.
Who the guide is written for, and what kind of document it is
A consumer guide from a professional body is advice, not law. It does not amend the Building Regulations, it does not create a duty on lenders and it cannot order anyone to alter a roof. What it does is record how chartered surveyors are expected to think about a product when it appears in a home they are valuing or inspecting. That is why it matters so much in practice: a surveyor who follows it will write up spray foam in a particular way, and a lender who reads the report will react to what is written.
The date and its meaning
The March 2023 date is part of the picture. Guidance of this kind describes the position at the time of writing, and the document can be revised. When a surveyor, buyer or solicitor quotes it to you, ask which version they are working from, and check the current text yourself on the RICS site.
The limits of the document
It is no technical standard for installing foam, no test method and no certificate. It does not say a roof is safe or unsafe. Nothing in it replaces looking at your particular roof, which is why the guidance keeps pointing back to qualified professionals and to the people you owe information to. We use it as a framework for questions, not as a verdict.
The central warning: dampness and uncontrolled condensation
The core of the guide is a warning about what happens when foam is put in wrongly. In the guide's words, a faulty installation is a route to dampness, with condensation running out of control and knock-on damage elsewhere in the house. Each phrase there is worth slowing down for.
Why the word is faulty
The guide targets bad installation, not the existence of foam. A roof that has been designed for it, with the right thickness, the right foam and the right provision for moisture, is a different thing from one where foam went on to whatever surface was available. Reading the sentence as a ban would be a misreading. Reading it as a warning about workmanship and design is closer to what it says.
What condensation is, in a roof
Condensation forms when warm, moist air meets a surface cold enough to turn that moisture into water. In a roof void, that surface can be the underside of a covering, a felt or a timber. Foam changes where the cold surface sits. With foam filling the space under the covering, the timbers behind it can end up cold and out of sight. If any moisture reaches them, it has nowhere obvious to go. Uncontrolled means nobody planned where the moisture would end up.
Why harm beyond the roof matters
The guide looks past the roof itself. Damp that starts in a roof void can reach ceilings, wall heads and the structure that holds up the covering. That is also why the guide matters to lenders: the thing they lend against is the whole building.
We cannot tell you from outside whether a particular roof is affected. What we can do is look in the roof void, take moisture readings in timbers we can reach, and photograph what we find. That evidence is the practical answer to the guide's warning.
Calculations and condensation risk checks before installation
The second main point is about what should happen before foam goes on. The guide says thermal calculations and condensation risk checks need to be undertaken by a qualified professional. This is a statement about process, and it is the most useful part for an owner who inherited foam from a previous one.
Questions it hands you
If foam was installed before you bought the house, you can ask the seller or the original installer a short list of questions. Were thermal calculations done? Was a condensation risk check carried out, and by whom? Does any paperwork survive? What product was used, at what thickness, and over what surface? The answers will not always exist, and that is itself information. A missing record does not prove a fault, but it removes one comfort a buyer, valuer or lender might otherwise rely on.
Why the paperwork carries weight
A condensation risk check is the proof that someone thought about where moisture would go. Without it, a surveyor has no way to tell a sound installation from a risky one except by looking at the timbers, and the timbers are often covered by the foam. That circle, where the thing you need to inspect is hidden by the thing you are inspecting, is the reason surveyors reach for words like further investigation.
If you hold any paperwork for the foam in your roof, keep it with the deeds and give a copy to your surveyor. It is often the least costly evidence you can offer.
What we add
An assessment from a roofer is not a replacement for design calculations made before installation. It fills a different gap: the actual state of the roof void today, measured and photographed. For the cost of that visit, see what spray foam removal costs.
Mortgage providers and insurers: the two checks it tells you to make
The guide does not stop at technical matters. It sends owners to two outside parties: the mortgage provider, to learn if lender policy accepts such products, and the home insurer, to learn the same about the policy on the house. These are listed as things to do, and they sit in the same list as the technical checks.
Why these two calls come first
A lender holds a charge over the building and an insurer carries the risk of damage to it. If either has a rule about foam, the owner finds out in the worst possible way when they discover it late: on a remortgage, a claim or a sale. The RICS wording encourages asking early, before the money is spent on installation.
What the guide does not tell you
It does not list which lenders accept foam and which refuse. A dated snapshot of lender behaviour exists elsewhere. In November 2024 the BBC looked into it, and Today's Conveyancer reported that some lenders would decline foam homes outright while others would judge each application on its facts. That is a news report, not RICS guidance, and positions change. Our page on spray foam and mortgages covers the lender side in detail.
Using the guide with your own lender
When you phone, quote the guide's wording and ask three things. Does your policy allow the product at all? Does it ask for particular evidence, such as a specialist report? And would the answer change if the foam was removed? Note who answered and when. A written reply is worth much more than a conversation.
Listed buildings: the line about reversibility
One passage deals with older and protected homes. The RICS treats foam as something that cannot be reversed, and says consent for putting it into a listed building is unlikely. Stroud District has 41 conservation areas, so the passage deserves attention here.
Why reversibility is the test
Conservation practice prefers work that can be taken out again without damaging the original fabric. Foam sprayed onto old timber, stone slates or the back of handmade tiles sticks to what it touches, and taking it off can pull at the material beneath. The guide treats that as the reason consent is unlikely. If you own a listed house, the starting point is a call to Stroud District Council's conservation team, because Stroud District Council states that protection is full and covers the whole building, whatever its grade.
If foam is already there
Foam that went into a listed roof without consent is a matter to raise with the planning team, not to quietly fix. Taking foam out may itself need consent if it touches the fabric that gives the building its listing, so ask before any work begins. For the specific questions about protected homes, see spray foam in a listed building.
Unlisted homes in conservation areas
The reversibility sentence refers to listed buildings, so do not stretch it to a house that is merely in a conservation area. Where the status is unclear, the planning team can confirm it. Replacing a roof like for like usually falls outside planning control, though listing or an Article 4 direction can alter that.
What the guide leaves open, and how we read it on a roof
A careful reading finds as much in the gaps as in the text. The guide does not say all foam must come out. It does not give a moisture reading above which a roof fails. It does not set a time limit. And it does not claim that foam installed with calculations and checks is a problem.
Reading it as a sequence
Taken together the points form an order of events. Before installation: calculations and condensation checks. At installation: correct work. After installation: lender and insurer policies, and, for a listed building, consent. When the sequence was followed, an owner has paperwork and the roof is likely to be in good order. When it was not, the next step is to find out what is actually there, which is an inspection, not an argument.
What we do with it
On a survey we work through the same sequence in reverse. We ask what documents exist. We look at the foam type and thickness. We take moisture readings in timbers we can reach and note any we cannot. Our guide to how spray foam is removed follows on for roofs where the evidence points to removal, and the answer on whether removal is always needed covers the roofs where it does not.
A note on language
You will see foam described as a banned or condemned product in some places. The RICS guide does not use that language, and we do not either. The sensible position is to treat foam as a risk to be assessed, using the checks the guide sets out, and to decide on what is found.
A checklist drawn from the guide for your own roof
Here is the guide turned into steps, in an order that costs least first.
- Find out whether foam is present and where. Look in the loft, and note whether the rafters and roof boards are visible.
- Gather any paperwork: invoices, product data, calculations, guarantees, and any condensation risk check.
- Phone your mortgage provider and your insurer, as the guide advises, and ask for written replies.
- If the house is listed, contact the conservation team at Stroud District Council before touching anything.
- Arrange an assessment that records foam type, thickness, adhesion and timber moisture readings with photographs.
- Decide on the evidence: leave, partly remove, or remove and re-insulate.
If the answer is remove
Removal and new insulation can fall within the Planning Portal thresholds of 25 per cent of the building envelope and 50 per cent of the roof. Over those, Building Regulations approval applies. We tell you which side of those lines your roof is on and send the notice to building control if the job needs one. Our written quote covers every task, backed by photographs of your own roof and by our 10-year workmanship guarantee, in writing. Our removal process guide describes the method.
Send us your address and a few photographs of the loft. If a surveyor has written about the foam, include the wording, because it tells us what your lender or buyer is likely to ask for.