May 4, 2025
Spray foam might look like a clean, quick job once it’s finished — but behind that tidy surface is a complex chemical process that continues long after the installers leave.
So if you’ve had spray foam applied to your loft or roof space (or are thinking about it), you might be wondering: how long before it’s safe to be in the house again?
The short answer: not immediately.
Here’s why — and what you need to watch out for.
Spray foam insulation is made by mixing two chemicals on site. As they react, they expand and harden — but during that reaction, they release volatile organic compounds (VOCs).
These fumes can:
Even if you can’t see it, the chemical reaction continues for 8 to 24 hours after installation — sometimes longer depending on temperature and thickness.
Most major spray foam manufacturers advise:
Despite this, many spray foam jobs in the UK have been done without proper aftercare — especially during the 2010s boom in quick-sell energy upgrades.
If installed correctly and cured fully, the foam becomes inert. But in the real world, we’ve encountered:
This is particularly risky in lofts that aren’t ventilated or homes with vulnerable occupants.
If you’ve already had spray foam installed and didn’t get clear instructions:
Or if you’re considering removal, we can help with that too — safely and without damaging your roof. Read more here.
Spray foam insulation needs time to cure — and during that window, it’s not safe to be in close proximity. If you’ve recently had work done or are planning to, make sure you understand the aftercare process.
And if the insulation’s been in for years but something doesn’t feel right, it might be time to take a closer look.
Contact us for honest advice, or browse our blog for more information on safety, removal, and modern alternatives.
Spray foam insulation isn’t just a mortgage issue — it can also raise concerns with insurers. Here’s how it affects cover, and what to do if your policy is at risk.
Read more >>Trying to remortgage but the survey flagged spray foam? Here’s why lenders are cautious — and what steps to take if you want your application approved.
Read more >>Spray foam won’t rot your roof on its own — but it can trap moisture against the timbers, leading to hidden damage. Here’s how it happens and what to look out for.
Read more >>