Why Is Spray Foam Hazardous?

Spray foam insulation was once seen as a clever fix for draughty homes and high energy bills. But over time, it's become clear that this type of insulation brings more risks than rewards — especially when used in roof spaces.

From hidden moisture and timber rot to health concerns and mortgage refusals, the hazards of spray foam are well-documented. At Countrywide Roofing and Insulation, we've helped countless homeowners across the UK safely remove spray foam from their lofts after things went wrong. In this post, we'll explain why spray foam is considered hazardous — and what to do if you already have it in your home.

1. It Traps Moisture and Damages Roof Timbers

Spray foam insulation is applied directly to the underside of the roof, sealing the loft space. While that may sound good in theory, it also traps any moisture that enters the area — which is where the real problems begin.

Closed cell spray foam is particularly problematic. It forms a rigid, airtight barrier that blocks ventilation. Even a small leak or buildup of condensation can lead to trapped moisture, which eventually seeps into the timber. Over time, that causes rot, mould growth, and in some cases, serious structural weakening.

Even open cell spray foam, which is softer and more breathable, can absorb moisture like a sponge — while hiding early signs of decay.

📊 Stat: Around 1 in 4 homes with spray foam insulation experience moisture-related issues within five years.

2. It Can Make Your Home Unmortgageable

Another major hazard is the impact on your property's value and financial flexibility. Most UK lenders and surveyors now treat spray foam as a red flag — and many will not approve mortgages or remortgages where spray foam has been applied in the loft.

3. Health Risks Linked to Spray Foam

Spray foam contains chemicals — particularly isocyanates — that can cause irritation to the skin, eyes, and lungs. During application, these are released into the air and can linger if the area isn't ventilated properly.

Poor installation or foam that begins to degrade over time can release unpleasant odours and harmful particles into the air. Some homeowners report respiratory problems, headaches, and persistent irritation — especially in poorly ventilated loft conversions.

While risk is highest during installation, long-term exposure can also cause concern — which is why safe and thorough spray foam removal is essential.

4. Removal Isn't Simple — But It's Often the Only Option

Once spray foam is installed, it doesn't just peel off. Especially in the case of closed cell foam, the material bonds tightly to the rafters and roof felt. Removing it requires skill, specialist tools, and care to avoid damaging the roof structure further.

That said, removal is often the only way to restore your property's value, breathability, and mortgage eligibility.

At Countrywide Roofing and Insulation, we're specialists in open cell spray foam removal and closed cell spray foam removal, and we handle each job with care — ensuring your roof is left in a safe, breathable state, ready for resale or refinancing.

Like Sealing a Wet Sponge in Plastic

Imagine taking a slightly damp sponge and sealing it in an airtight plastic bag. At first, it looks fine — but inside, the moisture festers. Mould grows, and decay sets in. That's exactly how spray foam behaves in a roof space. It seals in heat — and all the moisture and hidden problems along with it.

What Should You Do If You Have Spray Foam in Your Loft?

If you've already had spray foam installed, don't panic. But don't ignore it either. Here's how to deal with it:

 FAQs: The Hazards of Spray Foam

1. What are the top signs that I need closed-cell spray foam removal?

If you notice cracks, damp smells, mortgage refusals, or structural shifts, it could be time to remove the insulation. Discover the 5 most common red flags:
👉 Top 5 Signs You Need Closed-Cell Spray Foam Removal

In many cases, equity release is blocked or heavily restricted due to spray foam's effect on surveys and valuations. Here's how it impacts your financial options:
👉 Understanding Equity Release If You Have Spray Foam

While manufacturers claim lifespans of 20–80 years, real-world issues like poor installation, moisture, or roof damage can cut that down drastically. Find out what to realistically expect:
👉 What Is the Lifespan of Spray Foam?

Removal becomes necessary when spray foam affects mortgages, causes damp issues, or fails a home survey. Learn how to identify the right time to act:
👉 When and Why You Need Spray Foam Removal

Homeowners across the UK are removing it due to survey failures, property devaluation, trapped moisture, and restricted home improvement plans. Learn more:
👉 Why Are People Removing Spray Foam Insulation?

Closed-cell foam bonds tightly to surfaces, making it labor-intensive and risky to roof timbers if done improperly. Learn what makes it so tricky:
👉 Why Closed-Cell Spray Foam Can Be Difficult to Remove

Spray foam can trap moisture, block ventilation, and release chemical off-gassing if applied incorrectly — leading to health, structural, and financial risks. Learn the dangers:
👉 Why Is Spray Foam Hazardous?

Spraying foam directly onto roof tiles or felt can lead to decay, trapped moisture, and mortgage refusals. Here's why professionals advise against it:
👉 Why Shouldn't You Spray Foam Your Roof?

 Final Thoughts

Contact Countrywide Roofing and Insulation today for expert advice and a free, no-obligation removal quote.