Thinking About Spray Foam Insulation? Why It Could Derail Your Property Sale in South East London and Kent

Thinking About Spray Foam Insulation? Why It Could Derail Your Property Sale

At Integra Estates, we’ve witnessed a growing number of property sales being delayed — or even falling through — due to spray foam insulation. What may have once seemed like a clever way to improve energy efficiency is now raising serious concerns for surveyors, mortgage lenders, and buyers alike.

If you’re based in Beckenham, Orpington, Bromley, Chislehurst, Catford, Eltham, South east Londonor nearby areas, and you're considering selling your home (or buying one), this blog is essential reading

❓ What Is Spray Foam Insulation?

Spray foam is a liquid-applied insulation material that expands to form a solid foam. It’s often used in lofts and wall cavities to reduce heat loss and improve energy efficiency. There are two main types of spray foam: open-cell and closed-cell — and knowing the difference is crucial when it comes to understanding the risks.

🔍 What’s the Difference Between Open-Cell and Closed-Cell Spray Foam?

🟢 Open-Cell Spray Foam

Lightweight and breathable — but not suitable for roof spaces

- Structure: Contains cells that aren’t fully closed, giving it a soft, spongy texture.

- Air permeability: Allows airflow and water vapour to pass through.

- Insulation value: Has a lower R-value compared to closed-cell foam, so it’s less thermally efficient.

- Soundproofing: Offers excellent noise reduction.

- Risks: Often used in roof voids, where it can expand significantly and cover vital roof timbers. This makes it hard for surveyors to check for hidden issues like leaks or rot, leading to concerns from lenders.

✅ Verdict: While it offers breathability and soundproofing, it's still likely to cause problems when selling — particularly in lofts.

🔴 Closed-Cell Spray Foam

Dense and moisture-resistant — but often a deal-breaker

- Structure: Made of tightly packed closed cells, resulting in a rigid, solid material.

- Moisture resistance: Excellent barrier against water and vapour.

- Insulation value: High R-value per inch — extremely energy efficient.

- Structural impact: Adds rigidity to roof structures, but can trap moisture against timbers.

- Risks: Closed-cell foam is often an automatic red flag for surveyors. It completely masks timber, making it impossible to assess roof condition. If applied to a roof, most lenders will demand it be removed before mortgage approval.

❗ Verdict: Closed-cell foam is the most problematic type, especially in lofts and roofs. It’s harder to remove and more likely to be rejected by lenders outright.

⚠️ The Hidden Risks of Spray Foam Insulation

Even with a valid guarantee or installation certificate, spray foam insulation can cause serious headaches:

- Mortgage refusals – Many UK lenders will not offer mortgages on properties with spray foam, especially in the loft.

- Survey complications – Surveyors often cannot inspect roof timbers adequately, forcing buyers to walk away.

- Sales fall-through – Buyers may be advised against proceeding by their broker or solicitor.

- Costly removals – Foam removal can cost £4,000–£10,000, depending on the property and type of foam used.

- Extended time on the market – Properties with spray foam often take longer to sell and may fetch reduced offers

🧾 What to Do If Your Property Already Has Spray Foam

If you’ve already had spray foam installed, it’s not necessarily the end of the world — but you must be prepared:

- Gather all documentation – This includes warranties, installation records, and installer details.

- Get an independent timber report – Especially important if the foam covers roof timbers.

- Be open and upfront – Tell your estate agent and any potential buyers immediately.

- Consider removal – In many cases, the only way to proceed with a sale is to remove the foam entirely.

🛑 Why You Should Think Twice Before Installing Spray Foam

We strongly recommend against installing spray foam if you plan to sell your property in the next 5–10 years. While it may offer short-term insulation benefits, the long-term impact on your property’s value — and its saleability — could be significant.

Safer alternatives like mineral wool or rigid insulation boards are far more acceptable to lenders and surveyors.

📍 Areas Affected Across South East London and Kent

We’ve encountered issues with spray foam insulation in sales across

Addington Addiscombe Anerley Avery Hill Badgers Mount Bankside Beckenham Beddington Bell Green Bellingham Bermondsey Bickley Biggin Hill Biggin Hill Airport, Biggin Hill Blackfen Blackheath Blackheath Park Borough Brasted Brockley Bromley Camberwell Canada Water Catford Charlton Chelsfield Chevening Chislehurst Crofton Park Croydon, Surrey Crystal Palace Cudham Denmark Hill Deptford Downe Downham Dulwich Dulwich Village East Dulwich Elephant and Castle Eltham Eltham Park Farnborough Forest Hill Forestdale Gipsy Hill Green Street Green Greenwich Grove Park Halstead, Kent Harvey Gardens Hayes, Bromley Herne Hill Hither Green Honor Oak Park Ide Hill Kennington Keston Kidbrooke Knockholt Ladywell Lambeth Lee Lewisham Lower Sydenham Maze Hill Mottingham New Addington New Charlton New Cross New Cross Gate New Eltham Newington North Lambeth Norwood Norwood New Town Nunhead Orpington Park Langley Peckham Penge Petts Wood Plumstead Pratts Bottom Rotherhithe Selhurst Sevenoaks Shirley Shooter's Hill Shoreham, Kent Shortlands Sidcup South Bank South Bermondsey South Norwood Southwark St John's St. Mary Cray St. Pauls Cray Stockwell Sundridge Surrey Quays Sydenham Tatsfield Toys Hill, Westerham Upper Norwood Upper Sydenham Waddon Walworth Waterloo Weald, Kent West Dulwich West Norwood West Wickham Westcombe Park Westerham Woodside Woolwich

Thinking of selling your home and unsure about spray foam insulation? Speak to the experts at Integra Estates for honest advice and trusted guidance. Call us today on 0203 870 0000, email [email protected], or visit www.integra-estates.com to arrange your free property consultation.