next course of shingles. If there are corner
aroundanailshank.Thenhammerdownonthe
boards, snap chalklines between them to mark
tool’shandleuntilthehookcutsthroughthe
shingle courses, and off you go.
shank.Toavoiddamagingthereplacementshin-
However, if there are no corner boards, weave
glesasyoudrivethemintoplace,holdascrap
shingles at the building corners, alternating shin-
blockundertheshinglebutttocushionthe
gle edges every other course. This requires more
skill and patience than just butting shingles to
hammerblows.
trim boards but produces corners that are both
handsome and weathertight. Weave the corners
first, then nail up the shingles in between.
Because the starter course overhangs the bottom
of the sheathing 1⁄2 in. to 1 in., measure down
Fit shingles closely to window and door cas-
that amount at each corner, using a laser level to
ings. The top of the shingle course under a win-
establish level. After establishing the correct
dowsill should butt squarely to the sill. Because
exposure, as described above, shingle up each
this course needs to be shortened and will be
corner. As you work up the wall, snap a chalkline susceptible to splits, caulk the back sides. It’s also
from corner to corner to line up shingle butts.
wise to caulk the shortened top course of shingles
As you did on the first course, offset the verti-
under the eaves. Ideally, the tops of those shin-
cal shingle joints at least 11⁄2 in. between succes-
gles will also be protected by a rabbeted-out or
sive courses. If you have a partner, you’ll find it
built-up frieze, as shown on p. 161.
easier if each of you works from a corner toward
If you need to angle-cut shingle butts for use
the middle. Only the last shingle will need to
P R O T I P
along gable-end walls and dormers or need to
be fitted.
angle-cut shingle tops to fit under rake trim, use
Clapboards have a planed,
an adjustable bevel to capture the roof angle and
smooth front side and a rougher
transfer it to shingles. Such angle cuts are best
back side. using 100-grit sand-
made all at once, on the ground, using a table-
paper, lightly sand the smooth
saw. To notch shingles around windowsill ears
side to help finish coats of paint
and the like, use a cordless jigsaw. Finally, leave a
adhere, even if the clapboard
1⁄2-in. to 1-in. gap beneath dormer-wall shingles
is preprimed.
and adjacent roofing; otherwise, shingles resting
directly on roofing can wick moisture and rot
(see p. 89).
InStAllIng ClAPBOARDS
The following discussion assumes that you’ve
read this chapter’s earlier sections on layout and
that you’ve installed door and window flashing,
building paper, and exterior trim. It also assumes
that the building has corner boards that you can
When you weave the corners first, leveling the shingle
courses in between is largely a matter of snapping
chalklines between shingle butts at either end of the wall.
If you snap the chalkline slightly high, as shown, the
shingle butts will cover the chalk.
Exteriors
167
Rain-Screen Walls
In humid regions where housewrap and back-primed siding are not enough to pre-
vent rotted siding, some builders have retrofitted rain-screen walls to remedy paint
failure and soaked sheathing. Basically, rain-screen walls employ furring strips to
space clapboards out from the building paper, allowing air to circulate freely behind
the siding and dry it out. the reasoning is sound, and field reports are encouraging.
As sensible as this solution is, it’s not for every renovation. Rain screens require
careful detailing and a skillful crew. For example, if furring strips raise the siding
roughly 3⁄8 in., existing trim needs to be oversize already (5/4 stock) or built up to
compensate for the increased thickness of siding layers. Another option: home
Slicker® or Cedar Breather, a thin layer of nylon mesh, keeps siding off the
building paper.
Rain-screen walls allow air to circulate behind the siding
and encourage drying. Here, thin wood furring strips
raise the siding above the building paper; each strip is
centered over a stud.
As with any horizontal siding, level
clapboard courses. The corner board will be
trimmed flush with the bottom courses of
siding after the two adjacent walls have
been sided.
Note the rain-screen corner stop. These clapboards were too thin
(7⁄16 in., butt end) to miter, and the builder didn’t want corner
boards. So a clever carpenter fashioned this corner stop using his
tablesaw. The stop legs are the same thickness as the furring
strips affixed to the wall studs. To avoid splits, the corner stop
was predrilled and attached with stainless-steel screws.
A layer of nylon mesh over the building paper allows
better air circulation under wood shingles and siding.
The mesh and building paper overlay the cap
flashing.
168 Chapter 7
the Science of nailing Clapboards
zzzzzz Clapboard Details
Even though nailing up clapboards isn’t rocket science, four carpenters will give
51/4 in.
you five opinions on how to do it. here’s what you need to know:
actual width
(1x6 clapboards)
Stud center
nail roughly 11⁄4 in. from the bottom so nails don’t pierce the upper edge of
the clapboard underneath, especially if you’re installing 1x8 or wider clapboards.
6-in.-wide
Wide clapboards are more likely to split if they are inadvertently nailed at top
building paper
and bottom.
splines behind
joints
nail clapboards to stud centers. For guidance, snap vertical chalklines on
the building paper over the stud centers; offset the clapboard butt joints by at least
Nails barely
32 in. lined-up nails look better, especially if you’re using a clear finish.
above top of
clapboard below
If you’ll be painting the clapboards, take note. Carpenters set nails; painters
fill and paint them. Setting nails makes painters cranky, and if there are 1,000 to
4-in. exposure
set, painters will miss some.
Nails long enough
to penetrate
framing
butt the clapboards to. Otherwise, the clapboard
Sheathing
corners will require compound-miter joints,
Position clapboard joints over stud centers.
which require a fair amount of work and skill.
For the most weathertight joints, bevel-cut ends.
Materials. Clapboards are a beveled siding
Note: For clarity in this drawing, building paper
milled from re
dwood, red cedar, or spruce; for
between clapboards and sheathing isn’t shown.
best results, use Grade A or better. Preprimed
finger-jointed clapboards, made from shorter
lengths of high-quality wood, are a cost-effective
alternative. Clapboards come in varying widths
and thicknesses, but all are nominally 1-in.-thick
P R O T I P
boards that have been planed down. Thus, a
1x6 is actually 3⁄8 in. thick (at the butt) by 51⁄4 in.
wide; a 1x8 is actually
If painted
1⁄
clapboards outside
2 in. by 71⁄2 in., and so
on. Traditional clapboards come in varying
kitchens and bathrooms chroni-
cally peel, excess interior mois-
lengths, whereas finger-jointed products are
ture may be migrating through
manufactured in 16-ft. lengths; all are sold by
the siding. Add an exhaust fan,
the lineal foot.
and drive plastic shims under
To estimate the amount you need, calculate
clapboards in the affected
the square footage of your walls, less window and
area so moisture can exit. It’s
door openings. Then consult the table on p. 170,
worth a try.
which assumes 1⁄2 in. of overlap for 1x4 clap-
boards and 1-in. to 11⁄4-in. overlap for all other
sizes. It also factors in 5% waste. Order prep-
rimed (or prestained) clapboards. Prepriming
seals out moisture, saves tons of time, and keeps
the job moving. You will need a small amount of
primer on hand to touch up newly cut ends.
Nails. Buy 5d stainless-steel, ring-shank siding
nails, whether you’re painting the clapboard or
not. Stainless-steel nails cost four to five times as
Clapboards and other horizontal lapped sidings are less
much as galvanized nails, but it’s worth the peace
likely to cup if nailed to stud centers—indicated here by
of mind. Galvanized nails are fine 99% of the time,
the vertical red chalkline. Install strips of building paper or but if the coating breaks off, the nail will rust.
waterproofing membrane behind joints to keep water out. Moreover, the tannins in cedar and redwood can
chemically react with galvanization, which can
cause staining. Same with galvanized staples. For
every 1,000 lin. ft. of siding, buy 5 lb. of 5d nails.
Exteriors
169
installation. It’s worth repeating: Standard clap-
board exposure is 4 in. for 1x6 clapboards (actual
Factory-Finished Siding
width, 51⁄4 in.), but you may want to vary that
exposure by 1⁄4 in. or less between courses to help
If you’re thinking of installing cedar or fiber-cement siding, consider having it
align the clapboards with the window and door
factory finished. You can choose virtually any color, have paint applied uniformly to
casings.
all sides of the siding in a dust-free setting, then have it delivered ready to install.
The first course of clapboards typically sits
You’ll only have to make occasional touch-ups and seal cut ends, cutouts, and such.
atop a water table. First, flash the top of the
the price for the whole labor-saving operation is often less than it would cost you
water table with metal drip-edge to prevent rot.
to pay someone to paint it, and finishes routinely come with a 25-year warranty
To establish the correct pitch for that first course,
against paint failure.
rip a 11⁄4-in.-wide beveled starter strip from the
A lumberyard or paint manufacturer should be able to recommend a factory fin-
top of a clapboard. (Save the 4-in.-wide bottom
isher. this recommender can help specify the siding materials and the particulars of
waste rip for the top of a wall.) Tack the strip
the paint job, including price, and will be a valuable ally in the unlikely event that
atop the water table, and you’re ready to nail up
you need to make a claim on the warranty. Regarding specs, wood siding usually
the first course. The water table may not be level,
gets an alkyd oil primer to prevent bleed-through, and fiber-cement siding gets
but that’s OK; it’s better to avoid a noticeable gap
primed with latex. For all siding types, there are acrylic-latex finish coats.
between a level first course and an off-level water
In addition to its durability, factory-finished siding is predictable. the cost of a
table. In that case, take pains to level the second
job is based solely on the amount of siding being painted and the number of coats.
and all successive courses.
Start at one corner board and work all the
You won’t pay more if your house has one story or three because there’s no painters’
way across the wall, nailing clapboards to each
scaffolding required. And the caveats are relatively minor. to minimize retouching,
stud center they cross. Use only one nail at each
installers must take great care when handling the siding. new cuts must be painted
stud crossing, locating nails just above the top of
immediately after cutting so moisture doesn’t enter the dry siding. And color-
the clapboard below, as shown on p. 169. (If you
matched siding nails are slightly more expensive. But pay attention to the details,
nail through the clapboard below, you’ll split its
and you may not need to paint again for a quarter century.
thin, tapered edge.)
All butt joints should be square and centered
over a stud so that the ends of both boards can be
securely nailed. Remember to stagger joints by at
least 32 in. To further weatherproof the joints,
back them with strips of building paper; the
paper overlaps the top of the clapboard beneath
by 1⁄2 in.
zzzzzz homemade Clapboard gauge
For clean, square cuts, rent or buy a 10-in.
sliding miter saw with a 40-tooth or 60-tooth
carbide-tipped blade. And be prepared to recut
joints. When fitting the second board of a butt
joint, leave it a little long until you’re satisfied
with the joint. If it isn’t perfectly square on the
first try, you’ll have excess to trim.
When butting clapboards to corner boards
and jamb casings, use the homemade gauge
shown at left. Using the gauge to hold the clap-
Scribe
Clapboard needed
this line.
to cover 100 Sq. Ft.
CLaPboaRdSizE
LinEaLFEET
1x4
440
1x6
280
To fit clapboards closely to jamb casing,
1x8
200
make a gauge from 1-in. stock. Slip the gauge
1x10
160
over the clapboard, slide it next to the casing,
and mark the casing edge onto the clapboard.
170 Chapter 7
board tight to the trim, scribe the cut-off line
with a utility knife. Never fit clapboards so tightly
to the casing t
hat you need to force them into
place. If you cause window jambs to bow in,
sashes might bind. Where top courses abut the
underside of eave or rake trim, rabbet or build
out the trim to receive the top edges of the clap-
boards, as illustrated on p. 161. Caulk all build-
ing joints well with latex acrylic or urethane caulk
before nailing up the top course of clapboards.
Fiber-Cement Siding
One of the first engineered building materials,
fiber-cement (FC) siding has been around since
the 1940s. It fell out of favor after one of its com-
ponents, asbestos, was found to be a carcinogen.
However, new fiber-cement products are asbestos-
free, consisting of cellulose fiber (wood pulp),
sand, and portland cement. Available in a wide
range of sizes and textures, fiber-cement products
now include trim boards, clapboard siding, and
panels manufactured to simulate wood-shingle
Because fiber-cement siding and trim
courses. All can be factory-finish painted in the
stock are thin and brittle, carry planks
after it’s been notched or cut out, a fiber-cement
color of your choice.
on edge to avoid cracking them. It’s
clapboard is likely to snap if handled incorrectly.
also advisable to have two workers
Managing the silica dust created by cutting
Most fiber-cement clapboards don’t taper and
handling planks, especially when
fiber cement continues to be the workplace issue, are rather thin—typically 5⁄
cutouts further weaken them.
16 in. thick. That they
but better respirators, eye protection, and power
don’t taper is something of an advantage, however,
saws with integral dust catchers have made FC
because it creates a triangle of open space behind
much safer to work with. Fiber-cement siding
each course’s overlap through which air can cir-
paints like a dream, is impervious to insects and
culate and keep things dry. Consequently, it’s not
rot, and won’t burn. Once installed, it is stable,
essential that you install FC boards over a rain
durable, and virtually maintenance-free. More-
screen. Fiber-cement clapboards typically overlap
P R O T I P
over, it’s about one-third the cost of red cedar.
the board below by 11⁄4 in., so nail each clapboard
Given the declining quality and availability of
about 1 in. below its top edge so nail heads will
lumber—and the energy required to ship huge
Renovation 4th Edition Page 39