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Is It Safe to Stay in the House After Spray Foam Installation?

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.

What Happens During Curing?

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:

  • Irritate your nose, throat, and eyes
  • Trigger asthma or respiratory issues
  • Linger for hours or even days in poorly ventilated homes

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.

What Do Manufacturers Recommend?

Most major spray foam manufacturers advise:

  • No one should occupy the home for 24–48 hours post-installation
  • The area should be fully ventilated during and after application
  • Protective gear (masks and suits) is required for installers and anyone nearby

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.

Is It Still a Problem After That?

If installed correctly and cured fully, the foam becomes inert. But in the real world, we’ve encountered:

  • Lingering odours weeks after installation
  • Complaints of sore eyes, headaches, and breathing issues
  • Homes where people returned too early — and regretted it

This is particularly risky in lofts that aren’t ventilated or homes with vulnerable occupants.

What Should You Do If You’re Worried?

If you’ve already had spray foam installed and didn’t get clear instructions:

  • Ventilate the loft space thoroughly
  • Avoid sleeping directly beneath the insulated area for a few days
  • Contact the installer and ask what chemicals were used
  • If in doubt, arrange for an independent check

Or if you’re considering removal, we can help with that too — safely and without damaging your roof. Read more here.

Final Thoughts

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.

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