SPRAY FOAM INSULATION: WHAT YOU NEED TO KNOW BEFORE YOU BUY
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If you're planning to sell a property after your renovation, spray foam insulation can be a major red flag.
Many mortgage lenders refuse to lend on homes with it, meaning the property becomes unmortgageable. And that limits your buyer pool significantly.
For flippers, this is a serious issue. If your exit relies on a standard sale, spray foam will likely need to be fully removed before marketing the property. That’s not just a technical job—it’s a cost you need to factor in before making an offer.
Here’s what you need to understand:
The Two Types of Spray Foam
Closed Cell: This is the more compact, rigid type. It used to be common in residential buildings but is now mostly used commercially. It’s harder to remove, and therefore more expensive.
Open Cell: Softer and more flexible. Easier to remove, but you still need a full inspection to understand how it was applied.
The Key Cost Factor: What Was It Sprayed On?
If spray foam was applied directly onto roof tiles, removal could require replacing all tiles and battens.
If it was applied onto a membrane, you may only need to replace the membrane, tiles can be reused. That brings the cost down significantly.
The Usual Removal Process (for Closed Cell)
Spray foam is cut off the joists.
Roof tiles are removed.
Joists are cleaned, scraped and sanded to about 90% bare timber (which most lenders accept).
Roof is reassembled, reusing tiles if possible.
There are alternative methods (e.g. dry ice blasting) that might avoid removing tiles, but these depend on the type of foam and how it was installed.
Always get a specialist to inspect the property.
Real Cost Example
When I looked at a 4-bed house with closed cell foam sprayed directly onto tiles (roof footprint ~51m²), the removal quote was around £25,000.
That’s not a small adjustment to your renovation budget, so this step is crucial when doing your due diligence.
Bottom line:
If you’re buying to flip and you spot spray foam in the roof, don’t guess.
Get it inspected early and costed properly, before you make your offer.
Knowing how to handle issues like this is what sets professional flippers apart.
If you’re not sure how to run due diligence like this yet, that’s exactly the kind of thing we work through together, inside FLIPIT.