Gun Grade Expanding Foam

Gun Grade Expanding Foam for Airtightness & Condensation Control

Gun grade expanding foam is an essential product for improving airtightness within roof and insulation
build-ups. It is designed to seal gaps, voids and service penetrations that would otherwise allow uncontrolled air
movement, draughts and moisture-laden air to pass into roof structures.

Air leakage is one of the most common contributors to condensation problems in roofs.
Warm, moist air escaping through unsealed gaps can cool rapidly within roof voids, increasing the risk of
interstitial condensation. By sealing these gaps, expanding foam helps support a more stable and predictable
thermal and moisture environment.

This gun grade foam allows for controlled, accurate application compared to straw-applied foams,
making it particularly suitable for professional roofing and insulation work.
It is commonly used around insulation boards, between structural elements, at roof penetrations,
and at junctions where membranes and insulation meet.

Expanding foam should be used as part of a wider insulation and airtightness strategy.
While it does not replace membranes or vapour control layers, it plays a critical supporting role by closing
unintended air paths that undermine overall roof performance.

Typical applications

• Sealing gaps around rigid insulation boards
• Closing voids at roof penetrations and service routes
• Airtightness detailing at eaves, abutments and junctions
• Reducing draughts and uncontrolled air leakage

When used alongside insulation, ventilation products and correct detailing,
gun grade expanding foam helps create roof build-ups that perform as intended and remain durable over time.