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Serving Alberta's Roofing Industry Since 1961
BUR Section 2: Control Joints, Perimeters and Penetrations
BUR-2.1 Control Joints
Roofing control joints are required to prevent
structural movement or stresses within the roofing system from
damaging a Built-Up Roofing (BUR) membrane.
For new construction, for building additions and
for re-roofing, control joints shall be installed between the new
and existing roofing systems. The Warranty Certificate will only be
issued on self-contained roof areas/sections.
Two types of control joints are used for
roofing, construction expansion joints and roof area
BUR-2.1.2 Construction Expansion
The building construction expansion
joint is incorporated by the design authority when differential
structural movement is anticipated. Fully adhered membranes shall
incorporate an ARCA approved expansion joint at these
Roofing expansion joints typically are of double
curb/plate construction, fastened on opposite sides of the
For conventional BUR systems, the top of the
expansion joint shall extend a minimum distance of 200mm (8”) above
the finished roof surface.
Drainage openings are not permitted through roof
BUR-2.1.3 Roof Area Dividers
A roof area divider is incorporated to divide
the roofing system into manageable sections and to protect the
membrane from stress related damage.
For BUR membranes, roof area dividers are
required where membrane stress points are likely to occur, such as
at changes in roof deck direction or deck construction type.
For conventional BUR systems, the top of
the roof area divider shall extend a minimum distance of 200mm (8")
above the finished roof surface.
Where the roof system drainage slopes
away on both sides of the roof area divider with a minimum slope of
1:50 (1/4"/ft.), the roof area divider height may be reduced to a
minimum distance of 75mm (3") above the finished roof
Roof area dividers may be of single or
multi-plate construction and shall be fastened to the roof decking
to prevent displacement.
Roof area dividers shall be installed so that
the maximum dimension of the BUR membrane does not exceed 46.0m
(150 ft.) and shall be spaced so that the enclosed membrane section
does not exceed approximately 1394m² (15,000 ft²) in area.
Membrane level drainage openings are not
permitted through roof area dividers. Where drainage is required
through area dividers, drainage openings shall be installed no
lower than the top of the cant.
To receive a Warranty Certificate, the minimum
perimeter parapet height for a conventional roof design is 75mm
(3”) above the finished roof surface.
The top surface of the perimeter parapet wall
shall be sloped towards the roof when the width of the parapet is
greater than 100mm (4”). The top of the parapet wall must have wood
blocking installed which is capable of providing holding power for
nails and/or screws used to secure the metal flashing.
Gypsum board is not an acceptable substrate for
the interior (roof side) vertical surface of a perimeter parapet
A gravel stop perimeter detail is not accepted
for Warranty Certificate issuance.
BUR-2.3 Roof Penetrations
Where permitted and when installed in accordance
with the ARCA Warranty Ltd. Roofing Application Standards, BUR
membrane penetrations may be waterproofed with gum boxes, metal
flashings or curbs.
Specialty devices designed for this purpose
shall be pre-approved prior to installation.
Curb tops shall extend a minimum distance of
200mm (8”) above the finished roof surface.
Curbs may be of wood or metal construction and
shall be mechanically fastened to the structural decking. Curbs
shall be insulated.
Prefabricated metal curbs shall be manufactured
with no open corners.
Metal curb tops shall be designed to provide a
minimum 50mm (2”) counter flashing overlap.
Exposed penetrations through curbs shall
be placed no lower than 200mm (8”) above the finished roof
BUR-2.3.3 Plumbing Vent Flashings
Plumbing vents penetrating the roofing
system, that are not curbed, may be waterproofed with a lead
flashing, a conical one piece aluminum flashing or a pre-approved
specialty device designed for this purpose.
When leads are specified, the lead sheet shall
be sized to extend a minimum distance of 150mm (6”) over the
surrounding primary membrane. The underside of the lead shall be
cleaned to provide proper adhesion and set in a bedding of plastic
cement over the primary membrane. The top surface of the lead shall
be primed with compatible asphalt primer or plastic cement. The
lead flashing shall be stubbed and caulked to the vent stack hub
with oakum and plumbing sealant.
Spun aluminum vent flashings, when not
curb mounted, shall extend a minimum distance of 200mm (8”) above
the primary membrane surface, and shall have a minimum of 100mm
(4”) wide flange. The flange shall be set in a bed of plastic
cement and the top surface cleaned and primed to ensure proper
adhesion of the membrane flashing.
When curb mounted, the curb shall be sized so
the base flashing overlaps and extends down over the membrane
flashing a minimum distance of 50mm (2”) on all sides. The plumbing
vent flashing shall be mechanically fastened to the curb on each
side. Do not place fasteners through the horizontal surface.
Where vent extension pipes are required,
the base of the extension pipe shall be sealed into the vent stack
hub. The interior of the plumbing vent flashing shall be insulated
to reduce condensation.
Seal the junction between the base of
the neoprene collar and the horizontal surface of the aluminum vent
flashing with a compatible caulking.
BUR-2.3.4 Jack, Ventilator and
Roof jack, ventilator, and gooseneck
flashings may be supported at membrane level or may be curb
When installed at membrane level, the flashing
may not exceed 356mm (14") in diameter or on a side. Each flashing
shall incorporate a one piece base flange not less than 100mm (4")
nor more than 200mm (8") in width. A flashing sleeve/cone shall
extend not less than 200mm (8") nor more than 300mm (12") above the
base flange. For gooseneck flashings, the minimum flashing height
shall be measured to the throat of the bend. The sleeve connection
with the base flange shall be soldered. All other seams, including
gooseneck segments, shall be soldered/welded water tight.
The base flange shall be set in a bedding of
plastic cement placed over the primary membrane. The top surface of
the flange shall be cleaned and primed to ensure the proper
adhesion of the membrane flashing.
When curb mounted, the base flange shall be
sized to over lap and extend down over the curb base flashing a
minimum distance of 50mm (2") on all sides. The flashing shall be
mechanically fastened to the curb on each side. Do not place
fasteners through the horizontal flange surface.
BUR-2.3.5 Gum Boxes
Rigid service lines shall be
waterproofed using gum boxes.
Only armoured, thermoset-insulated or
thermoplastic-insulated flexible service lines are permitted and
shall be contained within a curbed enclosure or gum cup. The top
50mm (2”) of the gum cup shall be filled with two-part pourable
sealer and the flexible line must be supported until the sealer has
For new construction, gum boxes shall be of
one-piece construction incorporating a minimum 100mm (4”) wide
continuous horizontal flange with no open corners. Gum box sides
shall be sealed and shall extend a minimum distance of 100mm (4”)
above the primary membrane surface.
The gum box shall be packed with oakum or other
material to contain the sealer. The gum box shall be filled with a
minimum 50mm (2”) thick layer of rubberized asphalt sealer or a
pourable sealer and left crowned to shed water. Plastic cement is
not permitted to fill gum boxes and shall not be used for this
When re-roofing, gum boxes may be of a two piece
construction provided there are no openings when installed and the
rubberized asphalt sealer is contained.
When more than one service line occupies
a gum box, a minimum separation distance of 25mm (1") shall be
maintained between each service line and the gum box sides.
Three sided gum boxes require minimum
100mm (4") flanges attached to the parapet wall and must be
waterproofed with membrane flashing.
BUR-2.3.6 Fall Arrest Anchors
ARCA Warranty Ltd. assumes no liability relative
to the supply and installation of fall arrest anchors.
The Warranty Certificate does not include
warranty of the fall arrest anchor system or its performance except
as it relates to the watertight integrity of the roof membrane
flashing seal around anchor flashings.
ARCA Warranty Ltd. recommends that a
professional structural engineer, licensed in Alberta, design the
fall arrest anchor system. Installation, drawings, specifications
and conformance to current building and safety codes shall be
included in the professional engineer’s scope of work.
Fall Arrest Anchors shall be waterproofed
to ARCA Standards. Deck flanges shall not be fabricated less than
100mm (4”) nor more than 200mm (8”) in width.
BUR-2.3.7 Roof Mounted Photovoltaic
Enclosed roof sections that include photovoltaic
equipment shall be independently drained and shall have positive
drainage with a minimum slope of 1:50 (2%).
The total area of roof mounted photovoltaic
equipment shall occupy no more than 50% of the total roof
Only rack-mounted photovoltaic systems secured
directly to the structural roof deck will be approved when
installed in accordance with ARCA Roofing Application
Accessibility to roofing components shall be
incorporated into the photovoltaic equipment design.
A minimum clearance of 3000mm (10') shall be provided around
the perimeter of the roof area.
A minimum clearance of 1200mm (4') shall be provided between
rows of photovoltaic arrays.
A minimum clearance of 1200mm (4') shall be provided to access
all roof penetrations. There shall be a minimum 1200mm (4')
clearance on all sides of each roof penetration.
A minimum clearance of 300mm (12") shall be provided beneath
the photovoltaic equipment to permit installation of the roofing
system. Equipment supports shall be designed by a structural
engineer and shall conform to the Alberta Building Code.
Roof Warranty coverage of this section applies
to commercial buildings for leak repairs on roof systems for five
(5) or ten (10) year terms only. The cost to remove and replace the
photovoltaic equipment to facilitate access to the roof membrane
for investigation and repair of workmanship related leaks is not
included and is the responsibility of the building owner.
BUR-2.4 Roof Drains
The Warranty Certificate does not include
warranty of the roof drainage system except as it relates to the
watertight integrity of the roof membrane flashing seal around the
Provision for emergency drainage is recommended
in all instances and is a requirement when control flow drains are
incorporated into the roof drainage system.
BUR-2.4.2 Cast Drains
The Warranty Certificate requires that a minimum
25 kg/m² (5 lb./ ft.) lead sheet flashing be used with cast drain
assemblies. The lead flashing shall be sized to extend over the
primary membrane a minimum distance of 150mm (6”) beyond the
outside perimeter of the drain hopper flange. The lead shall extend
a minimum distance 25mm (1”) beyond the inner edge of the clamping
ring, used to secure the lead to the drain hopper. The lead
flashing shall be set in a full bed of plastic cement and the top
surface shall be cleaned and primed to ensure proper adhesion of
the membrane flashing.
The top hopper flange of the roof drain must be
approximately 12.7mm (1/2”) below the surface of the primary
Alternatively, a cast drain may be flashed
and sealed with a sand surfaced, polyester reinforced SBS Modified
Bituminous membrane in lieu of a lead sheet. The minimum size of
the membrane reinforcement ply shall be 762mm square (30” x 30”),
centred over the drain, and fully adhered to the top of the 4-ply
membrane and drain hopper flange with compatible elastomeric
mastic. The SBS membrane reinforcement ply shall be trimmed to the
edge of the drain bowl. The drain clamping ring shall firmly set
the waterproof seal to the drain hopper flange.
BUR-2.4.3 Retrofit Drains
Retrofit drains may be used for roof
replacements (re-roofing) when cast drains are not practical.
Retrofit drains shall be of spun aluminum or copper construction,
with a minimum 100mm (4”) wide flange. The flange shall be set in a
bed of plastic cement and the top surface shall be cleaned and
primed to ensure proper adhesion of the membrane flashing. The
drain size shall match that of the existing drain line. The
retrofit drain sleeve shall incorporate a seal to prevent back flow
from the existing drain line.
Galvanized sheet metal drop drains shall only be
used for exterior drainage locations, such as through an overhang.
A minimum 100mm (4") wide horizontal flange shall be soldered to
the pipe sleeve and shall be set in a bed of plastic cement. The
top surface of the flange shall be cleaned and primed to ensure
proper adhesion of the membrane flashing.
BUR-2.4.4 Scupper Drains
Scupper drains permit roof drainage through the
perimeter building elements, such as parapets. Scupper drains may
also serve as emergency over flow outlets. Scuppers may be open or
through-wall type fabricated with or without an exterior hopper.
When serving as primary drainage, the scupper shall be set so that
the scupper apron is at or below primary membrane level.
Scuppers shall be fabricated from
minimum 26 gauge galvanized sheet metal. Scupper flanges must
extend a minimum distance of 100mm (4”) over the primary membrane,
cant face and wall opening. Sheet metal flanges shall be set in a
bed of plastic cement. The tops of the flanges shall be cleaned and
primed to ensure proper adhesion of the membrane flashing.
Through wall scuppers shall be four (4) sided to
cover the upper scupper opening with sheet metal. The scupper
opening shall be waterproofed in accordance with good roofing
Where control of drainage is required, the
scupper assembly may include an exterior hopper and an attached
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