Why so much shaking ? | Home Inspections Bellevue-Seattle-Everett
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Damaged crawl-space shear wall
This home had substantial shaking from front to back during the earthquake a few years ago.
The blueprints for the home showed a full height foundation wall up to the floor joists in the area that had excessive shaking.
During the Home Inspection of the Bellevue-Seattle-Everett area home, I found a strip-footing with a 2 x 4 framed wall, approximately 3' high, up to the floor joists. The framed wall had been sheathed with 1/2" plywood on both sides. My assumption is that the builder failed to pour the wall and obtained the engineers and/or building departments approval to substitute the double sheathed wall for the poured concrete wall.
Since the original construction, this home has had a problem with excess moisture in the crawlspace. A prior homeowner and/or contractor performed work to increase ventilation.
It appears in order to increase cross ventilation, the sheathing has been cut out between every stud bay. As a result, the shear wall is worthless (except for holding the loads above) and the home is therefore prone to excess shaking or possible structural failure during future earhquakes.