DCI Products RafterVent - Manual (Page 2)

2
kerfs are essential for allowing drainage
and airflow between the horizontal strips,
but they take a considerable amount of
cutting and time: I mounted a dado blade
in a radial arm saw and cut
3 / 8 - by 3 / 8 -
inch kerfs a few inches apart along what
seemed like thousands of 12-footers. I
then nailed the furring strips over the
housewrapped wall sheathing, positioning
each strip above every butt line on each
course of shingles. The shingles went up
fine, but I didn’t plan my window, door,
and corner trim details very well. Shingle
butts stood proud of some trim elements,
and I cobbled together less-than-perfect
solutions to mask other problems caused
by the
3 / 4 -inch furring thickness.
Fortunately, there are now a couple of
commercial products available for creat-
ing vented rain screens with shingles. I’ve
used both nylon spacer mats and plastic
battens over the past few years and found
advantages and disadvantages with each. I
also worked out details for windows,
doors, and trim for these rain-screen sys-
tems, as described below.
Spacer mat. Home Slicker by
Benjamin Obdyke is the best-known
spacer mat available. It’s marketed specif-
ically for use with sidewall shingles and
lap siding, though other companies make
similar products for EIFS and masonry
walls that will also work with shingles
(see “Resources,” page 28). Home Slicker
is a corrugated matrix of nylon strands
about
3 / 8 inch thick that comes in approx-
imately 40-inch-wide rolls. It gets applied
with staples or cap nails over house-
March/April 2007
~
CoastalContractor
A spacer mat such as Home
Slicker goes up quickly with no
special layout, creating a 1 / 4 -inch
ventilation gap behind shingles.
It is important to cut Home
Slicker close to trim such as win-
dow casing and corner boards: If
you leave a space wider than
about 3 / 4 inch, the unsupported
shingle edge is likely to split.