Solutions for excellent air sealing

Air leaks are a thing of the past

When the building envelope is insufficiently airtight, unwanted and uncontrolled air currents lurk. This leads not only to poorer air quality and condensation problems, but also to a significant increase in our energy consumption. In light of current energy and gas rates, air sealing homes is almost a necessity to keep costs in check. But also to enable a switch to sustainable heating technologies such as heat pumps. 

Lecot responds to this with an extensive range of A-brand products. From airtight tapes, films, coatings and membranes to foam seals and rubbers, with which even the smallest air leaks are sealed in a high-quality manner.

Those looking to make their existing homes more sustainable often start with insulation. "In addition to cavity wall and roof insulation, replacing glazing is popular," according to Jeroen de Wilde, Field Sales Manager at Lecot. "The connection around the window frame, however, is still too often forgotten, and that's a shame. This space is often not insulated or made airtight. This can result in huge air losses, amounting to as much as 30%."

Lecot takes the airtightness of homes to the next level with Lecot Optimont, which focuses on the best products, optimal installation as well as good guidance for window and door manufacturers, joiners and contractors.

Ensure airtight insulation

The basic principle of airtight construction is to connect all elements in the building envelope in such a way that no more air can escape through holes and cracks, emphasizes Frank Putteneers, Structural Engineer and Airtightness Specialist at Lecot product partner Belga Plastics. 

"That sounds logical, but it is anything but. Both in the Netherlands and Belgium there is a strong focus on insulation. However, the airtight installation of this insulation is still too often forgotten. A missed opportunity, because as a result the effect of the insulation materials is largely lost." 

Putteneers likes to compare it to wearing a wool sweater in the winter. "When it is windless and you are not running too fast, you will be wonderfully warm. However, if it starts to blow and a thin windstopper is missing, then cold symptoms are inevitable. The wind then blows right through the sweater. The same applies to airtight construction and insulation. Insulation only makes sense if proper air sealing is applied."

When it comes to assembling window frames, the Netherlands and Belgium have different working methods. Still, the solutions are largely similar, Putteneers says. 

"Specific to the Dutch market is the use of a structural frame. Until a few years ago, the connection between this structural frame and the supporting structure was not sealed. We recommend that this be done by removing the old wooden joinery, applying an insulating (Flexifoam) PU foam and sealing it airtight with Belgafoil.^{SA-L IN} plaster connecting film." 

In the Belgian market, where frames are missing, the same foils are used but in a wider version. These airtight foils are self-adhesive and available in different types, such as vapor open and vapor tight. If the surface is not smooth enough, a liquid sealant such as Belgacoat can always be used.^BRUSH and Belgacoat^SPRAY. In other words, a suitable total solution can be found for every situation.

Replace window and door rubbers

Following on from the frame-wall connections, proper sealing of the moving parts is also important, according to De Wilde. "Windows are closed about 90% of the time. The rubber is almost always compressed, so over time the resilience will decrease. In addition, rubbers can dry out, causing leaks to lurk." 

With door draft seals, frequent use is precisely the reason for replacement, says Karel Vanderweeën, Group Manager for Window and Door Technology at Lecot. 

"When opening and closing, draft seals automatically slide up and down, making wear and tear inevitable. To restore moisture and draft proofing, we offer an extensive range of Q-LON polyurethane foam seals for wood, plastic and aluminum. These seals are highly elastic, have excellent rebound characteristics and are extremely resistant to temperature fluctuations."

Fix air leaks at the glazing bars

Finally, it is wise to address air leaks at the glazing bars. For aluminium and plastic window frames for example. Also for this, Lecot offers several A-brand products, such as the innovative SFI600 adhesive foam of Soudal. 

De Wilde: "This adhesive foam can be applied very accurately between the glass and the rebate, improving airtightness, thermal insulation and acoustic performance. In addition, the adhesive foam contributes to the rigidity of the sashes (rotating parts)." 

Says Vanderweeën, "For wooden window frames, we recommend a Lohmann structural dry glazing tape (SDG Tape), which structurally bonds the glass to the frame. This tape also guarantees optimum rigidity and stability. In addition, air leaks are eliminated."

Optimont concept

All mentioned air sealing products are part of Lecot's Optimont concept. Curious about the possibilities for your projects? Please contact your Lecot contact person.