Exterior Sheathing Options

Most wear on your home will come from external elements. Wind, rain, snow, ice and uv rays from sunlight will all cause your home to break down over time. Unfortunately there is little you can do to stop its final demise but choosing the right products during construction will help extend the life of your home.

In about 1950 new building materials standards improved the quality of available lumber. Timber mills began to test, grade and size dimensional lumber and by the end of the 1960s builders and architects could depend on uniform quality and sizes. In the late 1980’s 90’s Glue laminated materials replaced the need for steel beams and OSB became the standard decking and sheathing material.

Today OSB (oriented strand board) and other composite wood materials play a large part in both interior and exterior applications. However the one huge drawback of using OSB is how fast it will break down under high or even moderate moisture conditions. For this reason the choice of OSB must be backed up by proper water proofing techniques. Unlike other wood products once OSB has come into contact with water simple drying of the area will not return the product to good condition. Permanent structural damage can occur due to water contact in only a matter of a few days.

Tyvek and Tar Paper
Following proper instillation Tyvek house wrap material will let moisture inside the building escape and repel water from the outside. Tar Paper acts as a dam and will prevent moisture travel in both directions. If you are using OSB it is important to let the moisture escape so that it won’t build up and cause structural and potential Mold problems.

Since OSB has such potential for deterioration what are your other options?

Well half inch CDX exterior grade plywood is a better product and can be installed just as easy as OSB. CDX Plywood will most likely retain its strength even after some short term water contact. The only drawback is cost.

Another concern is the ability of the structure to withstand impact of debris during storms. Although all wood products have limitations CDX Plywood should perform better then OSB however there is a new use for an old product which probably will lead to honorific consequences in future homes.

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