Many home builders and homeowners who prefer using unfinished wood panels for remodeling and building projects are choosing new wood composites such as OSB sheathing because of its lower costs and increased strengths. This material is relatively new and unknown to some less experienced craftsmen who might be looking at alternatives to traditional plywood paneling. If you are interested in learning more about OSB sheathing and the advantages it offers, refer to the information below.
OSB Sheathing Uses
Because of special engineering and manufacturing processes, OSB sheathing can be used successfully for exterior walls, sub-flooring, and roof decking. The manufacturing process bonds wood strands, rather than wood plies used by manufacturers of plywood or pressed wood. These particles, when bonded with resin, produce a stronger and stiffer panel than other products used in similar types of construction projects.
Some OSB boards and panels can be custom ordered from the mill that produces them, but standard boards are finished without the usual knots, voids, and gaps often found in other types of wood composite panels. OSB boards typically are manufactured with smoother surfaces and nail lines that are marked during the manufacturing process. This marking makes installation faster and more efficient for workers who must attach these boards by nailing. Cupping, as often found in plywood sheets, is most often not found to be a problem in the OSB boards.
OSB Board Size Selection
Standard board sizes vary in thickness and are usually available in thicknesses from 1/4 inch to 3/4 inch. Custom-built boards can usually be ordered with non-standard thickness.
Manufacturers of OSB boards most often use smaller, more fast-growing trees for the wood in these composite boards, such as poplar and yellow pine. Some faster-growing hardwoods are used at times.
Protection Against Weather
OSB board edges that are unsealed may swell when they are unprotected. Boards exposed to heavy moisture can swell and warp. These unprotected edges are vulnerable to water absorption and can expand as much as 15 percent. However, OSB boards and panels tend to shrink less rapidly than those made of plywood. Because of the absorption properties of OSB boards, contractors often prefer to use plywood on edges such as those found on roof decking that is exposed to weather conditions. For boards and decking installed away from exposed edges, the OSB material is used on these same roofs because of its lower cost.
OSB Application and Installation
When used for the installation of window and door frames where there is a greater likelihood of expansion from variations in seasonal temperatures, manufactures recommend leaving a gap of about 1/8 inch between boards. You can also use edge clips to get needed spacing between boards. When attaching these boards, use the stronger wood screws, rather than drywall screws. Install these boards horizontally across wall studs. Always check local building codes for the required thickness of boards. Sub-flooring, for example, may require a different thickness than walls. Check building codes also for approved fasteners.
Once your OSB is in place, care for it properly to make sure it has a long, healthy life.