While it's usually cheaper to build a roof with trusses,
architectural details are easier to add if you stick-frame. We
frame roofs both ways, depending on the job; and we
occasionally use a third, hybrid approach: trusses for part of
the roof and stick-framing for the rest.
That's how we framed the roof on the house shown on these
pages. For the most part it's a straightforward roof, easily
stacked with trusses — but some of its details convinced
us that the hybrid approach would work best.
To begin with, the architect's plan showed several small
decorative gables perpendicular to the main roof, which we
stick-framed using California valleys. There's nothing unusual
about that, but the plan also showed 4-foot overhangs at every
gable, with barge rafters supported on purlins that appear to
extend from inside the roof structure. In addition, there was
to be a pair of oversized triangular gable vents under each
roof peak.
Normally on a straight truss roof, we would simply use
gable-end trusses. But the combination of the large louvered
vents and the large overhang forced us to stick-frame the gable
walls.
The plans also called for 3-foot-wide open eaves with 3x6
exposed rafter tails every 2 feet. To accommodate the tails, we
ordered snub-end trusses, which end flush with the top plate
(see Figure 1). Because the trusses were laid out on 24-inch
centers, this would allow us to sister the extended rafter
tails onto the truss top chords. In places where the truss
spacing differed, we would attach the tails to blocking.
Figure 1. To make it easier to add the
architect-designed 4-foot gable overhangs and 3-foot rafter
tails along the eaves, the author stick-framed the gable walls
and used snub-end trusses for the main roof.
Gable Overhangs
If we'd used gable trusses, we probably would have had to cut
through chords or web members to fit the louvered vents and the
purlins. Rather than try to special-order a gable truss that
would work, we decided it was simpler just to stick-frame the
gable walls.
To support the 4-foot gable overhang, we ran the purlin members
back to the first truss and attached their ends to solid
blocking (Figure 2). For extra strength we added an upside-down
beam hanger to resist the upward rotation.
Figure 2. Triple 2-by members passing
through the stick-framed gable walls form the 4-foot support
purlins for the deep overhangs. An upside-down beam hanger
secured to solid framing on the inside (above) helps resist
rotation forces, and a cap flashing protects the exposed
horizontal surface at the top end of each purlin.
Where each purlin passed through the gable wall, we nailed it
to a stud positioned for that purpose. The purlins were built
up from three 2-by members — a 2x6 sandwiched between two
2x8s — which permitted us to lap the stud where the
purlin pierced the wall and to nail from both sides. We also
put cripples beneath each side, for additional support.
On the outside of each gable, we installed a frieze board
against the wall, as well as a 3x6 rafter — supported by
the purlins — in the middle of the overhang and a 2x8 fly
rafter at the outer edge.
Rafter Tails
We cut the false rafter tails about twice as long as their
3-foot projection and nailed them to the side of the truss top
chords (Figure 3). We positioned them 1 inch below the upper
edge of the top chord so that the 2x6 T&G knotty pine
spec'd for the open soffit (thick enough that no roofing nails
would stick through it) would be flush with the 1/2-inch
radiant-barrier OSB on the rest of the roof.
Figure 3. Three-by-six false rafter tails
nailed to the top chords of the snub-end trusses penetrate the
wall sheathing to create the appearance of an open-eaves
stick-framed roof. They're positioned 1 inch below the top of
the trusses so that the 2x6 roof planking to be installed over
the eaves will be flush with the 1/2-inch OSB on the rest of
the roof.
After the tails were in place we installed the truss blocking
along the top plates, then lapped the wall sheathing up over
it.
T&G Soffit
At this point we were ready to finish sheathing the main part
of the roof with OSB and install the 2x6 beveled-edge T&G
at the eaves and gable overhangs (Figure 4). Like the rafter
tails, the fly rafters had been positioned an inch below the
tops of the trusses so that the exposed soffit would be flush
with the main roof sheathing.
Figure 4. Two-by-six beveled-edge T&G
pine completes the stick-framed look. At bottom, the completed
house before painting.
Jesse Christensen co-owns Christensen
Brothers Construction in Danville, Calif., with his brother,
Josh.