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* In high-moisture areas, we use CDX pressure-treated plywood, rust-resistant galvanized nails, and stainless steel staples to prevent deterioration from moisture. Professional building inspectors have told us that they have seen serious deterioration of plywood in retrofits that are less than 3 years old due to exposure to high moisture.
* All bolts are installed with special mudsill plates and/or compression washers in lieu of round washers. The mudsill plates we use increase the bolt's
strength by nearly 60%. Likewise, compression washers greatly increase the bolt strength and are required by all retrofit codes.
* Bracing of cripple walls requires that numerous 2" by 4" wooden blocks be attached to the mudsill, and the plywood shear panels are in turn nailed to these blocks. Quite often these blocks must be less than 14 inches long, and retrofit building codes require that 10 large nails be nailed into each of them. It is our experience that these short pieces of lumber often split when subjected to so much nailing, and this severely compromises the strength of the shear walls. Therefore, when splitting of the blocks is a problem, we staple these blocks rather than nail them, using structural grade stainless steel staples. These staples are equal in strength to nails, but they do not split the blocks.
* It is often necessary to cut holes in the plywood around vents, pipes, and other obstructions. Square and right-angle holes weaken the plywood in the corners of these cuts and can cause the
plywood to tear at these locations. Therefore, we cut all square and right-angle holes in the plywood to have curved radii in all corners to prevent this tearing.
* Pneumatic nail guns frequently produce overpenetration of nails into plywood which considerably weakens the strength of the shear panels. To prevent this, we finish hammering all nails by hand to
insure the nail heads remain flush with the plywood surface.
* All blocking material is green lumber having a high moisture content to prevent splitting of the blocks.
* All plywood shear panels have ventilation holes drilled into them as per guidelines of the American Plywood Association.
* The Uniform Building Code states that different types of wood require different sizes of nails to provide maximun strength. We are very careful to use the appropriate-sized nail for each
type of wood used.
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