OSB on the Roof
Bill Rose's article on roof ventilation ("Roof Ventilation
Update," 10/07) was an excellent review of the factors that
influence vapor accumulation in vented and unvented attics. At
the APA/Engineered Wood Association, we have been testing,
certifying, and studying the properties of OSB for over 25
years, so we do not share the concern that "we still know too
little about the moisture performance of this material."
We know the structural, dimensional, and physical limitations
of the product and provide installation guidance to ensure
proper performance. We also know that, similar to other
untreated wood products, OSB is subject to biological
degradation absent proper design, installation, and maintenance
of the structure.
An extensive source of technical and installation guidelines on
the topic can be downloaded for free at
APA/Engineered Wood Association
Drywall Butt Joints
Nice article ("Taming Butt Joints," 12/07) — but Greg
DiBernardo didn't mention one shortcoming: The wheel on the
ButtTaper is aluminum and picks up tiny crumbs of drywall that
get stuck because of the pressure you apply. This makes for a
bumpy ride after a while, and scraping the wheel clean many
times a day with your fingernail is no fun.
For the price charged, I would expect a hard stainless wheel
with a polished rim so the drywall crumbs don't stick to it. In
fact, I'm having my local machine shop make me a stainless
By the way, for small patches you can do the bevels easier with
a smooth, rounded tool; I use the top of my Channellocks.
Gluckman & Co.
Author Greg DiBernardo responds: That problem has never
been an issue for me. I assume anyone using setting compounds
keeps a water bucket close by for cleaning tools and the like
as work progresses; I just dunk the wheel in the water
occasionally and everything slides right off.
Because fiber-cement siding is so heavy, it's difficult when
working alone to hold it to a line, match up a butt joint, and
start the first nail or screw. Here's a simple solution:
I use two gauge blocks, one near each end, to provide stable,
accurate support until two or three fasteners are in place (see
illustration). If the siding needs to be tweaked a little, I
just slide a shim in between the block and the bottom of the
siding. Once the piece is fastened, I back out the screws in
the coil stock and reset the blocks for the next course.
Spring Grove, Minn.