Terry talks about Tyvek which is a rain shield that protects the house from moisture. When water goes through a homes siding, it hypothetically hits this barrier and runs down to the ground. Terry further notes that the rain shield does not provide air sealing; instead, all the air sealing is already taking place behind the Tyvek in the polyisocyanurate foam, OSB, and behind the OSB where the spray foam has been applied.
Furring strips are put over the Tyvek, so that when siding is placed over it, there is an air space between the siding and rain shield. In other words, air can circulate beneath the siding to dry it out if it gets too wet thus avoiding a possibility of deterioration. The window trim is then put up on top of the furring strips. A bug screen is then applied on top and bottom of the furring strips and Tyvek. The siding, fiber cement Hardie board, is finally put on. The practice of putting on furring strips on top of the rain shield is different from traditional building where this step is skipped; instead, the siding is put right on top of the rain shield.
Post time: Jun-28-2017