Henry Company Hot Rubberized Asphalt Installation Guidelines

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Henry Company Hot Rubberized Asphalt Installation Guidelines

Notice to the Reader:

The instructions provided below are reprinted from the manufacturer's own materials which were submitted to the RoofStar Guarantee Program for inclusion in this Manual. The reader is urged to check these against current publications issued by the manufacturer, to ensure accuracy.


Contact Address: See Membership List in Section 1.


Country of Origin: U.S.A. of Manufacture: Canada

Year First Installed
Canada: 1968

1 Description

The main components of Bakor 790-11 are specially selected blend of refined asphalts, synthetic rubber and mineral stabilizers. It is modified with additives to promote adhesion and improve low temperature flexibility. The membrane is 100% in solids and provides an immediate cure on cooling.

The system normally consists of two plies of 790-11 membrane reinforced with Bakor Polyfab, a polyester reinforcing fabric.

The system is constructed in the field by squeegee application of Bakor 790-11 hot applied, rubberized asphalt to achieve a monolithic, fully bonded waterproofing membrane with full adhesion to the deck to restrict lateral water movement.

Bakor 790-11 Tow ply Waterproofing System is used for waterproofing concrete slabs and split slab construction projects, both on horizontal and vertical surfaces.


  • Not intended for use as a permanently exposed surface. Must be protected by appropriate overlay.
  • Not recommended over lightweight insulated concrete.
  • Contact Henry Canada when using in direct contact with coal-tar pitch derivatives or products containing coal-tar pitch, concrete with curing compounds or additives, or substrates which have existing waterproofing materials already in place.
  • Do not heat above 215°C. Do not melt in direct fired, single-wall kettles.


Bakor 790-11 is typically packaged in 110kg (50 lbs) recyclable cardboard box, 48 boxes per pallet. Alternatively Bakor 790-11 can be packaged in 205L steel drums.

Bakor Polyfab reinforcing fabric is packaged in rolls .91m (36") x 182m (600' ) 194m (1800 ft.2) with an approximate weight of 11.34 kg (25 lbs.)


The waterproofing assembly / material information published in the RoofStar Roofing Practices Manual does NOT represent a complete set of the Manufacturer's published data, nor does it represent a detailed specification. The preparation of a detailed specification is the responsibility of the design authority.


.1 For use on concrete decks in commercial, industrial and institutional applications
.2 For use in new construction or in re-waterproofing existing structures
.3 Waterproofing systems can be applied to horizontal or vertical substrates


.1 Materials shall be delivered to the jobsite in undamaged and original packaging indicating the name of manufacturer and product
.2 Hot rubberized asphalt should be stored in closed containers outdoors.
.3 Store primer at temperatures of 5°C (40°F) and above to facilitate handling. Keep solvent away from open flames or excessive heat.
.4 Store roll materials on end.
.5 Melting equipment shall consist of an indirect fired kettle with a double shell containing a high flash point heat transfer oil or hot air type. Kettle shall include a mechanical agitator.
.6 Avoid overheating of hot rubberized asphalt. Recommend application emprature of the membrane is 180°C to 200°C (356°F to 395°F). Do not heat above 215°C (419°F).


.1 Environmental Requirements: no installation work shall be performed during rainy or inclement weather and on frost or wet covered surfaces.
.2 Protection: Temporary protection of the membrane shall be provided to prevent mechanical damage or damage from spillage of oil or solvents until such time as permanent protection is provided.
.3 Apply products in areas of adequate ventilation, and use proper protection to prevent burns. Refer to MSDS for more complee warning and product information.


.1 Canadian General Standards Board: conform to CGSB-37-GP-50M: Hot Applied Rubberized Asphalt for Roofing and Waterproofing.
.2 Miami Dade: NOA 08-1003.09
.3 Underwriters Laboratories


.1 Applicator Training, Field Technician assistant, specification and design assistance is available upon request.


.1 Perform work in accordance with the printed requirements of the membrane manufacturer and this specification. Advise designer of any discrepancies prior to commencement of the Work.
.2 Maintain one copy of manufacturers literature on site throughout the execution of the Work.
.3 At the beginning of the Work and at all times during the execution of the Work, allow access to site by the waterproofing membrane manufacturers representative.
.4 Submit documentation certifying that the primary membrane complies with CGSB 37-GP-50M.
.5 Materials used in this Section, including primers, mastics and membranes, and asphaltic protection boards shall be fully compatible and shall be produced by one manufacturer.


NOTE: Regardless of the materials listed below or anywhere else in these manufacturer's guidelines, only materials accepted for use in the RoofStar Guarantee Program, or accessories associated with those materials, may be used to qualify for a RoofStar Guarantee. To see a list of the manufacturer's products accepted for use in the RoofStar Guarantee Program, click on the link above.


Consult the list of Accepted Materials by clicking on the MATERIALS link above.

.1 Primary Membrane shall be Bakor 790-11 as manufactured by Henry Company Canada, a hot applied rubberized asphalt membrane meeting the requirements of CGSB-37-GP-50M.
.2 Fabric Reinforcement shall be Polybfab polyester fabric as supplied by Henry, a spun bonded polyester fabric sheet capable of allowing the membrane to bleed through adequately to provide a monolithic reinforced membrane system.
.1 Surface Primer: Primer for hot applied rubberized asphalt membrane and flashings shall be Bakor 910-01 as manufactured by Henry, meeting CGSB-37-GP-9M or Bakor 930-18, a polymer modified primer fully compatible with the primary membrane as manufactured by Henry.
.2 Flashing Membrane: Flashing membrane shall be Bakor 990-25, 60 mil thick, as supplied by Henry, a flashing membrane composed of a combination of butyl and EPDM polymers. Alternatively, modified bituminous flashing membranes made of SBS are acceptable and shall be modified PLUS ® NP180s/s as manufactured by Henry, an SBS modified bitumen membrane having a minimum thickness of 3.0mm and non-woven polyester reinforcement of 180g/m2 meeting CGSB-37-GP-56M Type 2 Class C Grade 2. The upper and lower surface shall be sanded and be fully compatible with the primary membrane.
.3 Expansion Joint Membrane: Expansion joint membrane shall be 990-25, 60 mils thick as supplied by Henry, a flashing membrane composed of a combination of butyl and EPDM polymers.
.4 Expansion Joint Membrane: flat vulcanized expansion joint membrane with fleece backing, Bakor EJ. Membrane to accommodate movement of up to: ±1" [±25 mm] / ±2" [±50mm] / ± 10" [±250mm] with 500% elongation at -40°F [-40°C] across its length and at all vulcanized points.
.5 Protection Course:
.1 Asphaltic board protection course shall be Bakor Protection Board an asphaltic core protection board as manufactured by Henry having the following physical properties:
1. Core: Mineral filled high melt point asphalt;
2. Top surface: Inert non-woven glass reinforcing mat with polyethylene film cover;
3. Bottom surface: Inert non-woven glass reinforcing mat;
.2 SBS modified bituminous protection course shall be modifiedPLUS® NP180gM4 as manufactured by henry, an SBS modified bitumen membrane havinga minimum thickness of 4.0mm (160 mils) and a non-woven polyester reinforcement of 180g/m2 meeting CGSB 37-GP-56M Tyep 1 Class A Grade 2. The upper surface shall have ceramic granules and the lower surface shall be sanded.
.6 Securement Bars: Securement bars shall be continuous aluminum, stainless steel or galvanized metal, 3 mm x 25mm in size and shall be pre-drilled for non-corrosive screw attachment on a maximum of 300mm (12") centers.
.7 Filter Fabric scrim shall be woven polyolefin or polypropylene fabric, resistant to water and ultra violet degradation as recommended by the insulation manufacturer.
.8 Rigid Insulation: Rigid insulation shall be extruded polystyrene meeting CAN/ULC S701, Type 4, to the thickness and density recommended by insulation manufacturer and designer.
.9 Drainage Composite shall be Bakor DB drainage composites as recommended by the manufacturer for each assembly condition.
.10 Pavers: Pavers shall be precast slabs meeting CAN 3-A23.1.2.
.11 Pedestal Supports: Pedestal supports for pavers shall be in accordance with the paver manufacturers recommendations.


.1 Ensure deck surfaces and substrates are acceptable for installation of the waterproofing system and in accordance with RoofStar Guarantee Standards. Report any discrepancies prior to installing the waterproofing system.
.2 All concrete surfaces shall be cured a minimum of 14 days and shall be dry. All concrete placed in vented metal pan decks shall be cured a minimum of 60 days.
.3 Concrete surfaces shall be wood float finish and uniform.
.4 Before application of hot applied rubberized asphalt, the substrate shall be clean and dry, free from surface water, ice, snow or frost, dust, dirt, oil, grease, curing compounds of any other foreign matter detrimental to the adhesion of the hot applied rubberized asphalt.
.5 Any scaling or laitant concrete shall be sandblasted off.
.6 Voids, cracks, holes, honeycombs and other damaged horizontal or vertical surfaces shall be repaired before application of the membrane.
.1 Apply primer uniformly at the rate recommended by the manufacturer avoiding an excessive or over-spraying application. Ponding of the primer is recommended.
.2 The primer shall be dry before applying the hot applied rubberized asphalt.
.3 At monolithic pour, use a strip of 150mm (6") wide Polyester Fabric.
.1 Seal cracks and joints between 3.0mm (1/8") and 12mm (1/2") in width with a 3mm (1/8") thick coat of hot applied rubberized asphalt membrane and a strip fo 150mm (6") wide flashing membrane, centred on joint. Extending membrane 75mm(3") beyond the sheet edges. Cracks between 1.5mm (1/16"_ and 3.0mm (1/8") may be treated with a 150mm (6") wide strip of polyester fabric set in 3.0 mm (1/8") membrane.
.1 Apply hot rubberized asphalt membrane to provide a thickness of approximately 3mm (1/8") to the vertical faces and a minimum of 200m (8") out onto the horizontal surface.
.2 Embed flashing membrane in the hot applied rubberized asphalt membrane, avoiding any wrinkles or fishmouths, extending a minimum of 75mm (3") out onto the horizontal surface and 75mm (3") up vertical. Lap ends of flashing membrane a minimum of 75mm (3").
3.5 EXPANSION JOINT (Elastomeric Flashing Sheets)
.1 At expansion joints, loop 990-25 flashing membrane down into joint, embedded into a 3mm (1/8") thick layer of hot applied rubberized asphalt membrane.
.2 Ensure that the depth of loop is minimum 35mm (1 ½"). Extend flashing membrane minimum of 150mm (6") on each side of joint. Seal end joints a minimum of 150mm (6") and seal with a 3mm (1/8") coat of membrane. Fill loop with membrane.
.3 Secure top of expansion joint sheet with continuous fixing bar.
.1 Install all components of the system in accordance with the manufacturer's most recent thickness of 3mm (1/8").
.2 The system is to be wholly encapsulated between the plies of hot applied rubberized asphalt waterproofing system.
.1 The area around the drains shall be coated with hot applied rubberized asphalt membrane at a thickness of 3mm (1/8").
.2 Flashing sheet shall be placed over the coat drain flange extending a 150mm (6") beyond the flange
.3 A second coat of hot applied rubberized asphalt membrane shall be applied over the flashing sheet at a thickness of 3mm (1/8").
.4 Apply clamping ring exerting sufficient pressure to affect a seal between clamping ring and membrane. Temporarily block all drains during the application of ballast, or other materials, which might block the drains. Remove blocking when work is not in progress and upon completion.
3.8 MEMBRANE FLASHING AT PROTRUSIONS (Membrane set in Hot Applied Rubberized Asphalt)
.1 At mechanical vent, protrusions and pipe flashings, provide flashing membrane set into 3mm (1/8") layer of hot applied rubberized asphalt membrane. Overcoat and seal with membrane. Install clamps as required.
.1 Ensure primed deck is ready to receive hot applied rubberized asphalt membrane.
.2 Apply membrane smooth, free from air pockets, wrinkles, or tears and to manufacturer's instructions. Ensure full bond of membrane to substrate.
.3 Apply first layer of hot rubberized asphalt membrane evenly to a minimum thickness of 2mm to form a continuous monolithic coating over horizontal and vertical surfaces including previously reinforced areas.
.4 Apply fabric reinforcing sheet and firmly press into first layer of hot membrane. Overlap fabric approximately 6mm (1/4") ensuring that a layer of membrane is present between overlaps. Apply second layer of membrane over the fabric to a minimum thickness of 3mm (1/8") providing a total thickness of 5mm (215 mils).
.1 While required and as detailed in drawings, Protection Boards shall be placed directly into hot 790-11 membrane.
.2 The protection boards may be placed butt ended or may be lapped 25 mm to 50 mm (1"-2").
.3 Stagger or offset joints of protection boards.
.4 At locations of change in direction, overlap protection board 150mm (6").
.5 The waterproofing membrane is not designed for permanent exposure. Protect membrane from job site abuse as soon as possible following membrane application.
.1 SBS modified bituminous sheet shall be rolled onto hot applied rubberized asphalt membrane while it is still warm and tacky.
.2 The separation sheet shall be lapped 100mm (3").
.1 Water test by ponding water a minimum depth of 2" for a period of 48 hrs. Check for leaks and repair if leaks are detected. Retest after repairs are complete.
.1 Final inspection of completed work shall be carried out by the owner's representative, the contractor and Henry.