Installation Guide
LOW SLOPE ROOF DETAILS
The minimum roof slope on which shakes and shingles
are recommended is 19 degrees. It is possible, however,
to apply shingles or shakes successfully to solid sheathed
roofs of lower slope providing a
special method of application is
followed (Figure 7). The prescribed
method provides a double roof on
which the shingles or shakes are
applied to a lattice-like framework
embedded in a bituminous surface
coating.
A conventional hot-mop (or
suitable roll-type) asphalt roof
should be applied over the roof
deck. With the final hot-mop
application 38mm x 90mm spacers
of Western Red Cedar or
preservative treated lumber are
embedded in the bituminous
coating. These spacers are installed
over the rafters at 610mm O.C.
and extend from eave to ridge.
Next, 19mm x 90mm or 19mm x 140mm nailing strips,
spaced according to the weather exposure selected for
the shingles or shakes, should be nailed across the
spacers to form a lattice-like nailing base. For example, if
610mm shakes are to be installed at a weather exposure
of 255mm, the nailing strips would also be spaced at
255mm on centers.
Finally, the shingles or shakes are applied in the normal
manner with a starter course at the eave and felt
interlays between each course of shakes (Figure 7).
HIP AND RIDGE DETAILS
Intersecting roof surfaces at hips
and ridges should be capped to
ensure a weathertight joint. Site-
made or factory assembled hip
and ridge units may be used, but
both types must have alternate
overlaps and concealed nailing
(Figure 8). Weather exposures
should be the same as the field of
the roof. Nails must be longer
than those used on the field of the
roof and of sufficient length to
penetrate 13mm into or
completely through the sheathing.
5
100mm overlap of felt
455mm felt interlay
2 nails per shake
610mm Handsplit - and -
Resawn Shakes
255mm exposure
380mm shake
starter course
915mm felt
underlay
Hot-mop
Solid sheathing
38mm x 90mm
spacers at
610mm O.C.
19mm x 90mm or
19mm x 140mm
nailing strips
Application of Shakes
to Low Slope Roofs
Alternate overlap
Cut back edge of shingles
or shakes on a bevel
Double starter course
Choose material of
uniform width between
100mm and 125mm
Fig 7: Application of Shakes to Low Slope Roofs
Fig 8: Hip and Ridge Application