Wind tightness

The wind seal prevents cold outside air from flowing through the thermally insulated construction. All the air circulation within the thermal insulation reduces its efficacy.

The wind seal is therefore always on the cold side of the construction.

We are now well aware that the airtight layer restricts heat loss due to ventilation on the one hand and, on the other hand, prevents the penetration of warm and humid ambient air into the construction and thus the dreaded condensation damage.

The airtight layer is always on the warm side of the construction.

Wind seal in the construction phase

Curtain walls are often left for months without any form of lining. There are different reasons for this and it occurs at any time of the year. Here the wind seal protects the thermally insulated construction against external factors such as wind, rain, snow, etc., which especially load the cross joints.

Wind seal in the usage phase

Here, it prevents the penetration of cold air into the thermal insulation joints, the nesting of small animals such as insects, maggots, spiders and mice as well as the spilling out of improperly fitted insulating sheets.

Water vapour diffusion

A wind seal must be extremely vapour-permeable, so that the moisture in the construction can escape unhindered into the ventilation space. Even during the construction phase there is a great deal of trapped moisture and then later moisture is produced in the interior of the building due to use.

Wind and weather protection

A wind seal must be airtight and rainproof so that it can fulfil its basic function. However, there are few materials that are rainproof and vapour-permeable at the same time! Unfortunately, the values are often glossed over in practice.

Mechanical characteristics

A wind seal must be stable and must not sag. In addition, a smooth surface facilitates the functionality of the ventilation.

Resistance

Wind seals must be non-flammable, UV stable, be able to cope with temperatures ranging between –20 °C to +80°C and also have a longevity that matches the useful life of the façade.

Clean, wrinkle-free processing

The wind seal must be laid flat and must not have any large wrinkles. This could impede the ventilation, and a flapping sound might even occur in extreme cases.

Joints and edge connections

The overlaps and connections must be sealed cleanly with suitable adhesive strips, so that the cold outside air cannot penetrate and the wind seal can flow behind. This would greatly reduce their effect.

Penetrations

Doors, windows, outlet vents, electrical pipes, fastening anchors, etc. must also be sealed airtight and rainproof. Especially the façade anchors represent a vulnerability that is not to be underestimated.