Re:Why Timber Towers Are on the Rise in France
by wahern on Thursday November 02, 2017 @01:17AM
(#15608022)
If it's covered, how can you tell when there's damage?
We recently had seismic plywood shear walls installed in our soft story garage, holding up our 2 stories of living space. A previous owner actually had shear walls installed in 1992, after the 1989 Loma Prieta earthquake. But the '92 retrofit used the wrong grade of plywood, and used screws instead of nails. Screws have poor shear strength. The panels were basically useless for seismic safety and had to be replaced.
The 90-year-old redwood studs looked surprisingly pristine. But one of the studs had some kind of termite or fungal damage. The entire stud, top to bottom, basically disintegrated in your hands; but everything else was in perfect shape, including the sills. There were no outward signs of this at all--neither on the stud itself, on adjacent studs, nor the top or bottom sill plates. It was bizarre. And it would have gone totally unnoticed and maybe even spread, completely undetected, had the old panels not been removed.
The shear walls weren't the only things improperly installed. The 1992 foundation bolts didn't use adequately sized washers, so with enough movement the bolt heads would have ripped through the sill plate. Again, this was hidden behind the wall panels.
I grew up in Florida trailer parks. To me anything covered is hiding something--cockroaches, termites, substandard construction. Were there no need for the shear walls, I'd much prefer to have exposed studs and a completely exposed sill plate, at least in the garage.
We recently had seismic plywood shear walls installed in our soft story garage, holding up our 2 stories of living space. A previous owner actually had shear walls installed in 1992, after the 1989 Loma Prieta earthquake. But the '92 retrofit used the wrong grade of plywood, and used screws instead of nails. Screws have poor shear strength. The panels were basically useless for seismic safety and had to be replaced.
The 90-year-old redwood studs looked surprisingly pristine. But one of the studs had some kind of termite or fungal damage. The entire stud, top to bottom, basically disintegrated in your hands; but everything else was in perfect shape, including the sills. There were no outward signs of this at all--neither on the stud itself, on adjacent studs, nor the top or bottom sill plates. It was bizarre. And it would have gone totally unnoticed and maybe even spread, completely undetected, had the old panels not been removed.
The shear walls weren't the only things improperly installed. The 1992 foundation bolts didn't use adequately sized washers, so with enough movement the bolt heads would have ripped through the sill plate. Again, this was hidden behind the wall panels.
I grew up in Florida trailer parks. To me anything covered is hiding something--cockroaches, termites, substandard construction. Were there no need for the shear walls, I'd much prefer to have exposed studs and a completely exposed sill plate, at least in the garage.