Is Spray Foam Bad for Roof Timbers?

Spray foam insulation is often promoted as an effective loft insulation solution, but its impact on roof timbers is widely debated in the UK property market.

How spray foam affects roof timbers

When applied directly to rafters, spray foam can:

• Reduce natural airflow in the roof space

• Trap moisture against timber surfaces

• Make early signs of decay harder to detect

Moisture and ventilation risks

Roof spaces rely on ventilation to regulate humidity. When airflow is restricted:

• Condensation can form on cold surfaces

• Moisture may become trapped within timber layers

• Long-term damp conditions can develop

Do all spray foam installations cause damage?

Not necessarily. However, lenders and surveyors focus on risk and uncertainty, not just visible damage.

If you’re concerned about spray foam in your loft, Carter Langfold provides professional spray foam removal services to safely expose roof timbers and assess the true condition of your property.