Mike Guertin's article (March/April 2007) on using a rain
screen was great. I am managing some restoration work for a
condo association, which may include re-siding two multi-unit
buildings to remedy severe peeling, bubbling, and chipping
paint on cedar clapboard siding. Currently, there is no air
space between the clapboards and the underlayment, and the
existing siding is not back-primed. It has absorbed enough
water over the last 12 to 15 years to make the paint bubble and
overflow with water. After the siding is torn off, we expect to
have to replace some rotted OSB sheathing, which we found on a
test wall. We are planning to use HomeSlicker behind the new
siding as recommended by a consulting engineer, and we are
considering using fiber-cement siding as well.
Do you have any recommendations for details on a clapboard
installation that are different from the cedar shake siding you
Gribin Construction, LLC
Michael Guertin responds: I don't use HomeSlicker beneath
clapboard. Personally, I don't like nailing lap siding over
this drainage mat, because it bounces too much and makes it
hard to hand-drive nails. I end up getting too many claps
A simpler and more cost-effective method for creating a rain
screen beneath clapboard is to apply vertical furring strips
over each stud location and around penetrations. Similar
flashing details can be used as noted in the article. I
typically use 3/8-inch pressure-treated plywood for furring
strips. First apply housewrap, then furring strips at stud
locations, then clapboard. You don't have to break clap joints
at studs, either — just install small blocks of
plywood behind the joints as needed. Make sure you use
fasteners long enough to penetrate through furring strips,
sheathing, and into studs by 1 inch.
For fiber-cement lap siding, I use the same furring method as
clapboard. Yes, I recommend back-venting fiber cement
— not so much for paint performance but to promote
drainage and help the siding dry. Fiber-cement siding is a
"reservoir" siding, just like wood, meaning it sucks up water
and holds it for a while then releases it (dries out). The more
opportunity you give fiber cement to dry front and back, the
better the wall will stay dry.
Heads Up on Soffits
Thank you very much for the January/February 2007 copy of your
magazine. It is very informative for anyone in the building
business in any coastal area of the U.S.
I was especially interested in the article about securing
soffits. It covered a number of areas that I have been telling
our architects and clients about for years.
Patrick F. Coussens
MCT Sheet Metal, Inc.