sheathingflat

Sheathingflat is not a widely standardized term in construction nomenclature, but it is used informally in some product literature and contractor discussions to describe flat-lying exterior sheathing panels installed on a building’s frame. The term highlights the planar, non-profiled nature of the panels, in contrast to curved, ribbed, or shaped panel systems.

Common materials used for sheathingflat include plywood, oriented strand board (OSB), gypsum board, and fiber cement. Typical thicknesses for wall applications range from about 1/2 inch to 5/8 inch for plywood or 7/16 inch to 1/2 inch for OSB, with thicker options employed for roofs or high-load areas. Panels are selected based on structural needs, fire resistance, and compatibility with the chosen weather barrier and siding.

Role and installation: Sheathingflat panels are attached to the framing with corrosion-resistant fasteners, spaced according to local code and panel type. Joints are staggered and often taped or sealed to form an effective air and moisture barrier when used in combination with a weather-resistive barrier or house wrap. The flat panels provide structural rigidity, contribute to roof and wall shear resistance, and create a stable substrate for siding or cladding.

Considerations: Proper installation requires dry panels, appropriate flashing at openings and penetrations, and correct detailing to manage moisture and ventilation. Compliance with local building codes and relevant standards (such as those for plywood, OSB, or gypsum sheathing) is essential, as is ensuring compatibility with the chosen weather barrier and siding system.

See also: Exterior sheathing, Plywood, OSB, Gypsum board sheathing, Weather-resistive barrier.