Fire-rated structural OSB panels with overlaid water-resistant barrier
A wood or engineered wood structural panel, such as, but not limited to, OSB (“oriented strand board”) or plywood, that is both fire-resistant and water resistant. The panel is factory-coated with a product that provides fire resistance. The treatment gives it a Fire-Resistant (FR) performance (for use in a one- or two-hour rated assembly). The panel also is overlaid or coated in a factory setting with a weather/water resistive barrier (WRB). The structural panel thus combines a fire-resistant structural sheathing and WRB product in one integrated panel produced at a factory prior for installation at a job site.
1. A method of producing a fire-resistant and water-resistant integrated structural panel, comprising the steps of:
producing wood strands;
treating some or all of the wood strands with chemicals or additives, or both;
forming, in a production line, a mat with one or more layers from said treated wood strands;
applying a resin-impregnated paper overlay to an upper surface of the mat;
applying, in said production line using a production press, heat and pressure to the mat and resin-impregnated paper overlay to form a board with a first surface and a second surface, wherein the first surface comprises the overlay;
preparing a slurry containing non-combustible magnesium oxide;
applying a first coating of slurry to cover the first surface or second surface of the board; and
curing the board.
2. The method of claim 1 , further comprising the step of:
applying a fiberglass veil or mat to the first coating of slurry.
3. The method of claim 2 , wherein the fiberglass veil or mat is saturated with slurry prior to application to the first coating of slurry.
4. The method of claim 2 , further comprising the step of:
applying a second coating of slurry over the fiberglass veil or mat.
5. The method of claim 1 , further comprising the step of:
applying chopped fiberglass strands to the first coating of slurry.
6. The method of claim 5 , further comprising the step of:
applying a second coating of slurry over the chopped fiberglass strands.