Timber & Moisture Risk After Spray Foam Insulation: What Surveyors Look for (and How to Avoid Problems)

Spray foam insulation doesn't just raise questions about energy efficiency — it raises serious concerns about moisture and timber decay, especially in roofs where it's been applied to rafters or boarding.

That's why many UK mortgage lenders now demand more than just spray foam removal. They want proof the timber underneath is sound, dry, and fit for lending.

In this guide, we'll explain:

• Why spray foam poses a moisture risk
• What surveyors and lenders are looking for
• How Countrywide Insulation tests, documents, and certifies timber integrity — giving you what lenders actually require

Why Spray Foam Can Cause Timber Problems

Spray foam bonds tightly to roof timbers, creating an airtight seal. This may reduce heat loss, but it also limits ventilation. The result: condensation becomes trapped, raising moisture levels within the roof structure.

Over time, this can lead to:

• Damp or swollen rafters
• Hidden decay
• Black mould or fungal growth
• Delamination of felt or roof boards

Even if the spray foam is removed, timber damage may remain — and surveyors will be looking for signs of it.

GOV.UK has issued detailed warnings about this in its report:
Moisture Risk of Spray Foam Insulation in Roofs

What Surveyors Are Looking for After Removal

If you're applying for a mortgage, remortgage, or equity release, expect the surveyor to:

They'll check for staining, black spots, cracks, soft timber, or sagging. Even minor damage can raise red flags.

Timber should be tested using a calibrated moisture meter. Readings above 20% are often flagged as "high risk."

Surveyors now routinely ask for:

• A spray foam removal certificate
• Photographic evidence
• Moisture test results
• Confirmation from a qualified professional

If you can't provide this, you may face delays or even rejection.

How Countrywide Insulation Addresses Timber Risk

We don't just remove foam — we help prove that your roof is safe and mortgage-ready.

Every spray foam removal includes:

• Moisture testing with digital readings
• Full photographic documentation
• A signed, detailed certificate of removal
• Notes on visible timber condition and ventilation levels

We use industry-standard tools and methods that meet the expectations of mortgage lenders, brokers, and chartered surveyors.

Our reports are commonly accepted without additional queries.

What Happens If Your Timber Is Too Wet?

If we discover high moisture levels, we'll explain the next steps clearly. This may include:

• Installing temporary or permanent ventilation
• Waiting for the timber to dry before certification
• Replacing affected timber if decay is advanced
• Upgrading underfelt or breathable membranes where required

In some cases, timber dries naturally within weeks after spray foam removal, especially with improved airflow.

We've Helped Hundreds of Homeowners Satisfy Surveyor Checks

From homes blocked by equity release lenders to sales delayed by unexpected survey flags, we've helped countless homeowners across the UK resolve timber concerns and get the green light from surveyors.

Our process is trusted because we:

• Are fully insured and qualified
• Provide clear, lender-friendly paperwork
• Understand what surveyors are really looking for
• Don't charge for inspections or initial assessments

Learn more about our spray foam removal and certification process

 Key Takeaways

• Spray foam can raise moisture levels in roof timbers, even years after installation
• Surveyors routinely ask for proof the timber is dry and structurally sound
• Proper removal, moisture testing, and clear documentation are essential
• Countrywide Insulation offers all of this — starting with a free inspection

 Book Your Free Moisture Assessment

 If your property has spray foam, or you've recently had it removed, don't wait for a surveyor to raise concerns. Take control now by getting it inspected properly.

Speak to a member of our team or book your no-obligation visit:
https://countrywideinsulation.co.uk/get-a-quote

Or learn more about what we do and how we help homeowners meet mortgage requirements:
https://countrywideinsulation.co.uk/spray-foam-removal