Air Permeability

Air leakage has been widely identified as the major source of heat loss from a building’s interior. Heat loss not only contributes to higher building running costs but increases unnecessary CO₂ emissions, due to the additional heating load required to replace it.

The critical element to achieve good airtightness is the flexibility of the cladding system in accommodating variances in steelwork tolerances. Inadequately designed or poorly installed steelwork can deflect under its own weight or under the weight of the gutters and the cladding system connected to it.

If a cladding system requires precise steelwork tolerances in order for installation to be completed correctly or is too rigid to accommodate any purlin sag or misalignment, then serious gaps may occur causing serious air leaks.

It is vital when considering a building’s design to take into account the previous airtightness performance of the cladding system and its ability to accommodate for some degree of flexibility that will inevitability be needed.

CA Building Products built up roof and wall cladding systems incorporates lightweight Non-Fragile liner panels which have the built in flexibility to cope with much looser steelwork tolerances than rigid panel systems.

This ability to follow the flow of purlins which have sagged or deflected has enabled CA Building Products systems to deliver tested air permeability results of as little as 1.03m³/hr/m² at a pressure differential of 50 Pascals using standard installation practices.

These impressive results confirm that by insisting on a cladding system that can deliver a superior level of airtightness, this can improve the thermal performance of the building envelope by as much as 34.4% at no extra cost.