Oriented strand board, or OSB, is a siding product sold in sheets or laps depending on preference. It comes in a variety of finishes made to resemble various hardwoods and stucco surfaces. Many people prefer using OSB as an alternative to other siding materials such as metal or vinyl, which aren't as strong or durable. OSB does have its downfall: moisture is its enemy. When using OSB on the exterior of a home, you should take special precautions to ensure that the finish withstands the weather and lasts for years to come.
Measure the thickness of the OSB currently on the exterior of your home. OSB ranges in thickness from 7/16 inch to 1/2 inch thick. Matching the old material with the new material is important to prevent damage from moisture.
Prime the OSB. OSB may come from the factory with a painted finish; however, many brands of the material do not have a finish at all. Moisture will cause OSB to expand during inclement weather and result in significant damage during freeze and thaw cycles. Seal both sides of the OSB and the joints with a quality waterproofing primer.
Measure and cut the OSB to the size you need. OSB is sold in 4-by-8-foot or 4-by-10-foot sheets. Whether you need a small piece as a replacement or are siding the whole exterior, you can find sheets to match your needs.
Align the OSB so that it's straight and square. Tack it into place using stainless steel siding nails. Stainless steel nails resist corrosion and nails strictly for siding have a larger head to prevent pull-through problems. Space nails every 24 inches along all sides of the OSB. Studs behind the OSB are on 24-inch or 15-inch centres, making it easy for you to align the nails and secure the OSB to the exterior.
Paint the OSB with two coats of a premium exterior topcoat. Use a topcoat that will stand up to the weather in your area. OSB will fare much better when painted with a paint that protects it from the elements.
Inspect the OSB often and repaint as needed to protect it from the weather. Install OSB at least 6 inches off the ground to prevent moisture issues from splashing rainwater. OSB is available with a tongue and grove finish; these boards are made to fit together like a puzzle and increase the strength of the exterior finish.
Route rain water through gutters and away from the siding to extend the life of the OSB.
Tips and warnings
- Inspect the OSB often and repaint as needed to protect it from the weather.
- Install OSB at least 6 inches off the ground to prevent moisture issues from splashing rainwater.
- OSB is available with a tongue and grove finish; these boards are made to fit together like a puzzle and increase the strength of the exterior finish.
- Route rain water through gutters and away from the siding to extend the life of the OSB.