A.Sal Alfano responds: Follow this procedure
to lay out shingle siding so the courses break on the same line
as the window trim: First, measure the window height and add
the width of any trim you might have, then divide by the
shingle reveal. Most of the time, you won’t have an even
number of courses, and you’ll have to adjust the shingle
reveal slightly. To do that, ignore the fraction and choose the
closest whole number; this will be the number of even courses
that will fit between the window trim. Then pull your tape
measure out to an even multiple of that number of courses, run
it at a diagonal next to your window (see Figure 1), and tick
off each multiple. These marks will be your course lines.
Let’s take an example: Say your window height,
including the head trim and apron, is 49 inches and your
average shingle reveal is 8 inches. Since 49 ÷ 8 = 6
1/8, you will have six courses (ignoring the fraction). To find
the exact width of each reveal, pull the tape out to some large
multiple of six, say 60 inches, and run it at a diagonal from
the point that will be the corner of the window head trim to a
level line extended from the bottom of the soon-to-be-installed
window apron. Mark the sheathing at 10, 20, 30, 40, 50, and 60
inches. You’ve now got even course lines that will break
on the window trim.
Repeat this procedure for the space between first- and
second-floor windows, for the space between the trim for the
second-floor windows, etc. Then, so you don’t have to
tick off all these different numbers all over the house,
transfer the tick marks to a couple of long pieces of lumber,
making two story poles. You can then leapfrog these as you work
your way around the building.
As for concealing the nails, the only way I’ve found
to do this is with a piece of trim. Since the trim on the sides
and at the top of the window won’t necessarily lay over
the siding, but the apron trim will, I usually rip the apron at
an angle (if it’s narrow) or notch it (if it’s
wide), as shown in Figure 2, previous page.
Sal Alfano, formerly a builder for 20 years, is now
editor of the Journal of Light Construction.