Roof Sheathing High Wind Areas

Underlayment in high wind areas i e where wind speeds are 110 mph or greater must be secured with corrosion resistant fasteners spaced no more than 36 inches apart.

Roof sheathing high wind areas.

In very windy areas solid sheathing is often used. Fasteners should be 3 8 inch from panel ends and 3 8 inch from panel edges see hints below. At intermediate supports fasten panels 12 inches on center. D for the roof framing to wall connection use an h1 or equivalent connector attached on the exterior sheathing side of the exterior walls.

Special wind regions and topographic factors identified in asce 7 engineered design is recommended. When the wind pressures the roof it lifts the sheathing off the roofs structure and frame. The type and number of fasteners required for a specific application is obviously an the engineered wood association apa. In areas prone to hurricanes and high winds loss of roofing materials and sheathing is a primary concern.

If the sheathing is properly installed there will be no damage made by high winds. High wind building codes such as sstd 10 99 and the wfcm call for structural panels to cover from the top of the top plate to the bottom of the bottom plate or mid band to meet combined uplift and shear values. The roof to wall connection under high wind loads is subject to both uplift and shear due to positive or negative wind pressure on the walls below. Uplift resistance of the roof sheathing.

Windstorm panels are engineered to allow the use of the continuous sheathing methods allowed by building codes. Roof slopes greater than 4 12 require only one layer of underlayment. Sheathing type typically 15 32 inch or thicker panels are required in high wind areas. Use panels rated as exposure 1 or better.

Building codes regarding the type number and spacing of fasteners must be followed. In some regions the common practice is to place a moisture barrier over open sheathing to keep out wind driven rain. When the sheathing is solid you can choose a proper material. In high wind areas more fasteners may be required.

Oriented strand board osb or plywood can be used although plywood will provide higher nail head pull through resistance. For pitched roofs wear skid resistant shoes. As a best practices approach an augmented underlayment can provide an effective secondary. The sheathing is the fastened to the rafters it acts like a top layer of the roofing.

Consult with local codes and builders for the accepted practice. The ability of a roof sheathing panel to resist high winds is directly related to how well it is secured to the roof framing. Increase the uplift resistance of the roof sheathing. Shingle and shake roofs may also be applied to solid sheathing at exposed eaves and rakes and similar locations.