SS-5.1 Decks
SS-5.1.1 General
.1
Cedar shakes and shingles shall be applied to a
continuous wood decking, spaced sheathing is not permitted.
.2
For new construction recommended decking
thickness is 11.1mm (7/16") O.S.B. or 12.7mm (1/2") inch thick
exterior grade plywood roof sheathing.
.3
For reroofing minimum deck thickness shall be
9.5mm (3/8") exterior grade sheathing.
SS-5.1.2 Strength
.1
The roof framing and decking shall be designed
of sufficient strength so that they will support the anticipated
load such as construction loads. Roof decks shall be free of
damaged, deteriorated or decayed wood.
SS-5.1.3 Surface
.1
The surface of all roof decks to which a roofing
system is to be applied shall be sufficiently clean and dry so that
proper attachment may take place.
.2
Roofing over existing roofing materials is not
permitted, tear off old materials to expose the decking.
.3
Repair damaged or deteriorated decking with
similar material prior to reroofing.
SS-5.1.4 Slope and Exposures
.1
For issuance of the Warranty Certificate the
following slope and exposure requirements apply:
-
Cedar Shingles
-
3:12 (1:4) to 4:12 (1:3)
Use standard shingle application (See Table 1 for exposure)
-
Greater than 4:12 (1:3)
Use standard shingle application (See Table 1 for exposure)
-
Less than 3:12 (1:4)
Not warranted. (See ARCA Manual, Division 1 Slope Chart for system type acceptance.)
-
-
Cedar Shakes
-
4:12 (1:3) and Greater
Use standard shake application
-
Less than 4:12 (1:3)
Not warranted. (See ARCA Manual, Division 1 Slope Chart for system type acceptance.)
-
SS-5.1.4.1 Table 1 - Cedar Shakes and Shingle Exposures
| Maximum Weather Exposures | |||
|---|---|---|---|
| TYPE | LENGTH | ROOF SLOPE 3:12 to 4:12 | ROOF SLOPE 4:12 & steeper |
| SHINGLES |
|
|
|
| SHAKES |
|
|
|
SS-5.2 Roofing Materials
SS-5.2.1 General
.1
Cedar shakes shall be No. 1 grade, mediums or
better meeting the requirement of CSA 0118.1-97.
.2
Cedar shingles shall be No. 1 grade meeting the
requirements of CSA 0118.1-97.
.3
To record material grade and mill name a label
taken from the site material shall be submitted to ARCA for each
project.
.4
Materials shall be adequately labeled so that
proper identification of the materials can be made.
SS-5.2.2 Protection and Storage
.1
Rolls of felt shall be stored on end, covered
and out of danger of water penetration.
SS-5.2.3 Application Limitations
.1
No roofing material shall be applied when the
weather or the condition of its substrate is such that the required
installation procedures could not be followed or which would
jeopardize the performance of the roofing system.
SS-5.2.4 Nails
.1
Nails used for roofing shall be
corrosion-resistant roofing or box nails conforming to ASTM
F1667-13 "Driven Fasteners: Nails, Spikes and Staples". The nails
shall be stainless steel or hot dipped galvanized.
Revised
2015-04
.2
Nails shall have sufficient length to penetrate
through sheathing, or a minimum of 25mm (1") into lumber roof
decking.
.3
Nails shall have a head diameter of not less
than 4.8mm (3/16") and a shank thickness of not less than 2.0mm
(.083")
SS-5.2.5 Staples
.1
The attachment of cedar shakes and shingles with
staples is not permitted.
SS-5.3 Flashing at Intersections
SS-5.3.1 Materials
.1
Sheet metal flashing shall consist of not less
than:
-
15 kg/m2 (3 P.S.F.) thick sheet lead,
-
0.41mm (30 ga.) Z275 thick galvanized steel,
-
0.56mm (16 oz.) thick copper,
-
0.60mm (22 ga.) thick aluminum
-
or approved alternates.
SS-5.3.2 Valley Flashing
.1
Open valleys shall be used for cedar shake and
shingle roofing.
.2
Where sloping surfaces of roofs intersect to
form a valley, the valley shall be flashed with minimum one (1) ply
of self adhering S.B.S. modified bituminous membrane plus one layer
of sheet metal valley flashing.
.3
Centre minimum 914mm (36") wide sections of
S.B.S. membrane over valley centre line and uniformly adhere to a
clean and dry deck surface. Overlap and seal membrane end laps a
minimum distance of 150mm (6").
.4
Centre minimum 600mm (24") wide sections of
sheet metal valley flashing over the S.B.S. membrane and fasten in
place. Where adjoining roof areas differ in pitch, the metal
flashing shall incorporate a minimum 25mm (1") high central
Λ - break upstand to control water run off.
.5
Mark water channel width by snapping chalk lines
on the metal flashing starting at the ridge a minimum distance of
50mm (2") on either side of the valley centre line. Taper channel
width from the ridge to the eaves at the approximate rate of 12.7mm
(1/2") for every 2440mm (8’) of valley length. Cut units at
chalk lines and fasten each with two (2) nails placed no closer
than 150mm (6") from either side of valley centre line.
SS-5.3.3 Intersection of Shake and Shingle Roofs and Walls
.1
The intersection of shake and shingle roofs at
walls or chimneys shall be protected with flashing in accordance
with the Alberta Building Code.
SS-5.3.4 Chimney Saddles
.1
Chimney saddles shall be installed where the
upper side of a chimney of a sloping roof is more than 762mm (30")
wide. For details see the Alberta Building Code.
.2
For chimneys less than 762mm (30") wide a
chimney saddle need not be installed if the intersection between
the chimney and roof is protected by one ply of self adhering
modified bituminous membrane and a sheet metal flashing that
extends up the chimney to a height equal to not less than one sixth
the width of the chimney, but not less than 150mm (6"), and shall
extend up the roof slope to a point equal in height to the flashing
on the chimney, but not less than 1.5 times the shake
exposure.
SS-5.4 Eave Protection and Angle Flashing
SS-5.4.1 Eave Protection
.1
Eave protection shall extend from the roof edge
a minimum distance of 900mm (3‘) up the roof slope to a line
not less than 300mm (1’) inside the inner face of the
exterior wall. (See ARCA Technical Bulletin on Ice Dam
protection.)
.2
Eave protection is not required
-
over unheated garages, carports and porches
-
where the roof overhang exceeds 900mm (3 ft) measured along the roof slope from the edge of the roof to the inner face of the exterior wall
-
on roofs with slopes of 8:12 (1:1.5) or greater.
SS-5.4.2 Materials
.1
Eave protection shall be laid beneath the
starter strip and shall consist of one of the following:
-
No. 15 asphalt-saturated felt laid in two plies lapped 480mm (19") and cemented together with lap cement.
-
No. 25 glass fiber coated base sheet
-
Self adhering S.B.S. modified bituminous membranes.
SS-5.4.3 Drip Edge Flashing
.1
The installation shall include prefinished or
galvanized sheet metal rake and eaves drip edge flashings. The drip
edge flashing deck flange shall extend a minimum distance of 75mm
(3") onto the roof decking and shall be nailed at maximum 400mm
(16") centres prior to the application of the eave protection or
shingles. Space vertical flange 6.4mm (1/4") from fascia.
.2
All exposed flashing edges shall be
hemmed.
SS-5.5 Shake Interlay Felts
SS-5.5.1 Materials
.1
Minimum one (1) ply No. 15 shake felt interlay
shall be provided beneath each course of cedar roof shakes.
SS-5.5.2 Installation
.1
Interlay shall be laid in strips not less than
457mm (18") wide between each course of shakes with the bottom edge
of the underlay positioned above the butt line, a distance equal to
double the exposure of the shakes.
SS-5.6 Shingle Underlayment
.1
Minimum one (1) ply No. 25 plain felt or two (2)
plies No. 15 felt underlay shall be provided beneath cedar
shingles.
.2
Underlay shall be laid as a strip not less than
900mm (3') wide along eaves and 300mm (1') wide along hips and
ridges with minimum 50mm (2") side laps.
.3
Apply underlayment felts in courses laid
perpendicular to roof slope to cover entire field of roof decking
not covered by eave protection. Underlayment shall lap eave
protection a minimum distance of 100mm (4"). Fasten underlayment
with sufficient nails to hold in place.
SS-5.7 Ventilation
.1
Every roof space or attic above an insulated
ceiling shall be ventilated with openings to the exterior to
provide unobstructed vent area of not less than 1/150 of the
insulated ceiling area. Vents may be roof type, eave type, soffit
type, gable-end type or any combination thereof, and shall be
uniformly distributed on opposite sides of the building. Roof vents
shall be equally distributed so that approximately 50 percent of
the required vent area is located near the lower part of the roof
and approximately 50 percent of the required vent area is near the
ridge. For exceptions see Alberta Building Code Section 9.19.1,
Venting.
SS-5.8 Cedar Shakes
SS-5.8.1 Size of Shakes
.1
Shakes shall be not less than 457mm (18") long,
not less than 100mm (4") nor more than 350mm (13-3/4") wide with a
butt dimension of not less than 12.7mm (1/2").
SS-5.8.2 Spacing
.1
Joints shall be spaced a minimum of 9.5mm (3/8")
and a maximum of 14.3mm (9/16") between adjacent shakes and offset
a minimum of 38mm (1-1/2") at the joints so that joints in
alternate courses are staggered.
SS-5.8.3 Fastening of Shakes
.1
Shakes shall be fastened with a minimum of two
(2) nails located approximately 19.0mm (3/4") from the sides of the
shakes and 38mm (1-1/2") above the exposure line.
SS-5.8.4 Application of Shakes
.1
The starter course shall be minimum one course
of minimum No. 2 cedar shakes or shingles overlaid with the
specified grade of cedar shakes.
.2
Butts of first course shakes shall project 38mm
(1-1/2") beyond the fascia.
.3
A 457mm (18") wide strip of No. 15 interlay felt
shall be laid over the top 100mm (4") of the shakes and extend on
to the sheathing 356mm (14"). The bottom edge of the felt shall be
positioned above the butt of the shake at a distance equal to twice
the weather exposure.
.4
Straight-split shakes shall be laid with the
froe-end (the end from which the shake has been split and which is
smoother) towards the ridge.
SS-5.8.5 Hips and Ridges
.1
Intersecting roof surfaces shall be capped to
ensure a watertight joint.
.2
Weather exposure for capping shall be the same
as the field of the roof.
.3
Prior to the application of the capping cover
the shakes on either side of the ridge or hip with a strip of
minimum No. 15 felt extending a minimum distance of 100mm (4") on
either side of the hip or ridge centre lines.
.4
Nails shall be longer than those in the field of
the roof and of sufficient length to penetrate 25mm (1") into
lumber roof decking or completely through the sheathing
SS-5.9 Cedar Shingles
SS-5.9.1 Size of Shingles
.1
Shingles shall not be less than 400mm (16")
long, not less than 100mm (4") wide with butt dimension of not less
than 9.5mm (3/8").
SS-5.9.2 Spacing
.1
Joints shall be spaced a minimum of 6.4mm (1/4")
and a maximum of 9.5mm (3/8") between adjacent shingles and offset
a minimum of 38mm (1-1/2") at the joints so that joints in
alternate courses are staggered.
SS-5.9.3 Fastening of Shingles
.1
Shingles shall be fastened with a minimum of two
(2) nails located approximately 19.0mm (3/4") from the sides of the
shingles and 38mm (1-1/2") above the exposure line.
SS-5.9.4 Application of Cedar Shingles
.1
The starter course shall be minimum one course
of cedar shingles of the same material as the field shingles
overlaid with the specified grade of cedar shingles.
.2
Butts of the first course shall project 38mm
(1-1/2") beyond the fascia.
.3
Succeeding courses of shingles shall be fastened
ensuring that alternate course joints do not align and in any three
(3) courses, no two (2) joints shall be in direct alignment.
SS-5.9.5 Hips and Ridges
.1
Intersecting roof surfaces shall be capped to
ensure a watertight joint.
.2
Weather exposure shall be the same as the field
of the roof.
.3
Prior to the application of the capping cover
the shingles on either side of the ridge or hip with a strip of
minimum No. 15 felt extending a minimum distance of 100mm (4") on
either side of the hip or ridge centre lines.
.4
Nails shall be longer than those in the field of
the roof and of sufficient length to penetrate 25mm (1") into
lumber roof decking or completely through the sheathing.