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Shear(wall) Madness!
Shearwalls just aren't what they used to be. Because of new requirements in the Building Code, many of the narrow shearwalls that worked yester-year, are no longer up to snuff. As a result, homeowners, architects, engineers and contractors are faced with difficult decisions that will affect window and door placement.
The old code allowed plywood shearwalls to have a height to width ratio of 3.5 to 1. This means that if your house had a 9' ceiling height, all the plywood shearwalls needed to be at least 2'-7" in length (9' ¸ 3.5 = 2'-7").
The current building code requires that any plywood shearwall must have a height to width ratio of at least 2 to 1. This means that if your house has a 9' plate height, now all the plywood shearwalls must be at least 4'-6" in length. So those nice, long doors and windows that you had your eyes on might have to be just a little smaller to satisfy the current building code requirements.
Why did they change it? Yep, earthquakes.
But don't despair! All is not lost if you just can't seem to find that extra length of wall needed to make a plywood shearwall work. There are alternatives that you have at your fingertips to replace the old plywood shearwall. One option is a pre-fabricated shearwall element that satisfies the building code requirements without conforming to the 2 to 1 height to width ratio.
Two of the common systems available to you are the Simpson Strong-wall and the Hardy-Frame. Each element is pre-fabricated and shipped to the site already built. You just need to install these wall elements per the manufacturer's specifications.
Another option in place of the plywood shearwalls, are steel moment frames. These are steel members that are specially welded together to form a rigid frame that can withstand vertical and lateral loads. Steel moment frames generally cost more than shearwalls.
But when you need to get that opening just a little wider and you can't seem to get a plywood shearwall to work, options are available for you to make it fit.
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