Ventilation and Cavities
It is particularly important that there should be no ingress of moisture where there is no air gap or cavity, and if the timber frame is untreated and kiln dried. Moisture from within the building can accumulate due to condensation, leakage or from the building use. Horizontal cladding, fixed directly to the structure without a cavity behind it, can inhibit natural venting.
When using cedar or treated timber with plain galvanised or AZ coated steel, designers should be aware that interaction between the timber and metal can occur if these materials remain wet.
Metal wall cladding should have some provision to remove condensation, which occurs when the humidity is high or when there is a significant diurnal temperature differential. Condensation form on metal more frequently when the walls are insulated and the building is heated.
Cavity construction is recommended for horizontal cladding in all areas that are exposed, or where ventilation is inhibited and the metal cladding may suffer from the effects of condensation.
- Log in to post comments