British rigid Urethane Foam Manufacturers' Association

Gap sealants

Building Regulations quite properly cite excessive air leakage as a major source of unwanted heat loss from buildings. Consequently, for the first time they have brought in limits and testing for this source of unwanted emissions – not only of heat but of CO2 resulting from the heating process.

Expanding polyurethane gap sealants are the ideal way to maximise air tightness of both dwellings and non-domestic building envelopes. This is principally due to their uniquely favourable characteristics. The closed cell structure of expanding polyurethane gap sealants is impermeable to liquid water and possesses a thermal conductivity in the order of 0.030 W/m².K.

Expanding polyurethane gap sealants are simply injected into a gap, e.g. around a door frame at installation or when being refurbished, where it subsequently expands to fill the uneven gap and bonds the door frame to the masonry with a strong rigid and impervious sealant. The product will also seal all other “incidental” gaps which characterise building today, namely around window frames, pipes and cables (passing through masonry walls) or other gaps bonding well to metals, plaster, wood, stone, brick and most plastics.

Expanding polyurethane gap sealant is easy to use, offers excellent adhesion to most building surfaces, dries tack free within 10 minutes of application and excess is simply trimmed with a knife. The finished surface can then be painted, plastered or cement rendered to prevent attack by UV light.

Expanding polyurethane gap sealants have been widely available for more than 25 years and will not only facilitate a design conforming to the new regulations but will also make a significant contribution to the reduction of a client’s fuel bills.