In residential buildings, the building envelope consists of roof and wall underlays and claddings as well as penetrations through these elements, such as windows and doors.
On some residential buildings, the roof cladding not only serves to prevent moisture entering the building, it also plays an important role in the seismic performance of the structure. It may act as a diaphragm and transfer lateral seismic forces to the vertical framing elements and down to the foundations. On other buildings, however, the choice of roof cladding may be entirely architectural and be based on factors such as appearance, cost, durability, local environmental conditions or maintenance requirements.
The risk posed by wall claddings varies a great deal, and the types of wall cladding are much more varied than roof claddings.
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