BUR Section 5: Insulation

BUR-5.1 General

1. Primary insulation is the system component that provides the major portion of the thermal performance of the roofing system. The location of the primary insulation can vary depending on the roofing system design type.
2. For ARCA Warranty Ltd. acceptance, insulation products must be tested by a certified testing agency, approved by the Standards Council of Canada, such as the Underwriters’ Laboratories of Canada (ULC) or a Canadian Construction Materials Centre (CCMC) evaluation listing to verify compliance to an existing insulation standard. Third party certified thermal insulation products are accepted by specific manufacturer and product name, and are not accepted generically for inclusion under the Warranty Certificate Program.
   

   *REVISED 2012-03

3. To eliminate confusion during the tendering process, it is recommended that the design authority specify roof insulation by the type and thickness of insulation to be used. Specifying insulation by thermal resistance values may lead to confusion during the construction process as insulation thickness affects the design heights of other building components, such as perimeters, curbs and sleepers.
4. Roof insulation shall be protected during shipping and site storage to prevent moisture infiltration and damage. No insulation material, either primary or secondary, is to be installed when its moisture content exceeds the manufacturer’s stated equilibrium moisture content. Surface moisture should be allowed to dry. Wet or damp insulation that cannot be dried must be removed and replaced with dry insulation.
5. When specifying plastic foam insulation, the design authority must ensure compliance with Alberta Building Standards relative to the use of thermal barriers, as this falls outside the expertise of the roofing contractor.
6. Only new insulation shall be installed in new conventional insulated roofing assemblies.
   

   *ADDED 2017-11

BUR-5.3 Primary Insulation

1. The primary insulation shall be uniformly adhered to the vapour retarder in a full application of hot bitumen, with an approved adhesive or mechanically fastened through the vapour retarder to the structural deck.
2. Insulation boards shall be tightly butted together and installed in a staggered pattern. Sloped or tapered insulation may be installed in a soldier or staggered pattern. Gaps at board joints greater than 6.4mm (1/4″) in width shall be filled with insulation.
   

   *REVISED 2020-12

3. When multi-layers of primary insulation are specified offset board joints by a minimum distance of 150mm (6″) from the preceding insulation layer.
4. When insulation is adhered with adhesive or hot bitumen, restrict board size to no greater than 1200mm x 1200mm (4 ft. x 4 ft.) dimensions for proper adhesion.

BUR-5.5 Asphalt Core Boards

1. Asphalt core board may be substituted for the secondary insulation layer over selected primary roof insulation when its application is approved by the primary membrane manufacturer.
   

   *ADDED 2013-10

2. Polystyrene insulation forms the primary insulation layer, the asphalt core board shall be comprised of two (2) 3.2mm (1/8”) thick layers of butt edged asphalt core boards. Each cover board layer shall be adhered with hot bitumen using the “mop and flop” back coating application method. Offset board joints of the board a minimum of 150mm (6”) from the underlying layer.
3. One layer of minimum 3.2mm (1/8”) thick asphalt core board is acceptable over faced insulations that are not heat sensitive for direct mopping application.

BUR-5.7 Polyurethane Foam Adhesive For Insulation And Asphalt Core Board

BUR-5.7.1 General

1. A primary membrane manufacturer’s accepted low-rise two component, chemical cure, polyurethane foam adhesive, when used in compliance with the manufacturer’s written application instructions, may be used to uniformly adhere accepted insulation and asphalt core boards to one another, to accepted vapour retarders, insulation and substrates.
2. The primary membrane manufacturer’s insulation adhesive(s) have been evaluated by ARCA Warranty Ltd. for specific applications and are not accepted as general purpose roofing adhesives and are not to be substituted for other accepted primary membrane manufacturers insulation adhesives.
3. Prior to dispensing foam, store adhesive at recommended application temperature and ensure adhesive shelf life date has not been exceeded.
4. Foam insulation adhesives may be dispensed to clean moisture free substrates by wand or spray equipment applied in accordance with adhesive manufacturer’s application rates. For wand applications, maintain proper adhesive ribbon size and spacing for roof field, perimeter and corners. When spraying, maintain minimum coverage rates.
5. Protect newly applied foam adhesive from contamination prior to bonding roofing components. Follow adhesive manufacturer’s post application requirements for weighting, rolling or walk-in insulation boards into the uncured adhesive to prevent air gaps from forming between insulation boards and their supporting substrate.
6. When polyisocyanurate roof insulation forms the primary insulation layer, insulation boards shall not exceed 1200mmx1200mm (4 ft. x 4 ft.) in size.
   

   *ADDED 2015-01

BUR-5.7.2 Accepted Roof Insulation Adhesives

1. The adhesives listed below by membrane manufacturer have been evaluated and accepted for specific applications. Accepted adhesives are not general purpose roofing adhesives and are not interchangeable amongst membrane manufacturers.

Polyurethane Foam Insulation Adhesive

Two component low-rise, chemically cured urethane foam adhesive for the attachment of selected rigid roof insulation and cover boards to one another and to fully adhered vapour barriers.

Other Insulation Adhesives

When approved for application by the membrane manufacturer and accepted by ARCA Warranty Ltd. on a project by project basis.