Tell me more, DUOTACK® SPF Adhesive

Q&A about DUOTACK SPF Adhesive function and installation.

Q: What is DUOTACK SPF Adhesive?

A: DUOTACK SPF Adhesive is a low pressure, two-component spray polyurethane foam adhesive specially formulated by SOPREMA. DUOTACK SPF was designed to adhere SENTINEL HFB membranes to approved substrates in a spatter pattern application and to adhere insulation and coverboards to approved substrates or together in a ribbon or bead application.

Q: How is the product sold?

A: DUOTACK SPF Adhesive is sold as a complete kit containing both the A & B side components and a hose and nozzle kit, so that installers have everything they need for a quick and easy application.

Q: Does the product require equipment for application?

A: There is no special equipment required for application; the kit comes with everything you need to apply the product. Many contractors are requesting self-contained kits to eliminate the need for Pace Carts or Predator Rigs which can sometimes break down and impede construction timelines.

Q: How is the product applied?

A: There are two application methods for this product: PVC membrane adhesive (spatter) and insulation or coverboard adhesive (ribbon)

Membrane Adhesive (Spatter):

Hold the dispensing gun 3-4 feet above the approved substrate, spray adhesive in an even coverage pattern (approximately 60 - 75% surface coverage). Applying too much adhesive can result in a decreased coverage rate and applying too little coverage may affect adhesion. Product cure times can range from one to eight minutes depending on ambient and substrate temperatures. Do not apply more adhesive than the length of PVC that can be installed within the bonding time frame. Roll the PVC membrane into place and immediately broom the membrane into the adhesive then roll the membrane with a weighted roller. Protect end laps and selvedge edges of the membrane from overspray during application. Should overspray onto the top (or non-fleece portion) of the membrane occur, clean immediately with approved cleaner.

Insulation and Coverboard Adhesive (Ribbon):

Hold the dispensing gun no further than 2 feet above the approved deck or insulation (multiple layers possible) substrate, spray adhesive in a ribbon application. Ribbon should be 2.5” wide and spacing will depend on wind up-lift requirements; consult the manufacturer’s recommendations. Maximum spacing for these ribbons is 12 inches o.c., though 6 inches and 4 inches o.c. are used in perimeters and corners, respectively. Once applied, immediately place the insulation/coverboard into the wet adhesive and do not allow the adhesive to skin over. Maintain constant pressure/weight on the boards while DUOTACK SPF Adhesive cures, usually in minutes but this may vary depending on environmental conditions.

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Q: How should SENTINEL HFB membranes be installed?

A: When membranes are installed, it is best to barn-door (butterfly) the membrane, which entails rolling the membrane completely out then rolling half of the membrane on to itself lengthwise. Apply the adhesive at 60-75% coverage and allow the adhesive to set (1-8 minutes depending on temperature) then roll the membrane into place. Broom the membrane then apply a 150 pound weight roller to ensure complete contact of the membrane to the substrate.

Q: Are there any special storage requirements?

A: DUOTACK SPF should be stored at 50°F - 80°F (10°C - 27°C) in a dry environment and in its original packaging. Do not store in direct sunlight or near heat source. Prior to use, condition tanks so that they reach a temperature between 70°F - 90°F (21°C - 32°C). Conditioning may take up to 24 hours to ensure chemical has reached optimal application temperature.

Q: What are the approved substrates?

A: DUOTACK SPF Adhesive may be applied over the following prepared substrates:

Compatible Roof Decks & Substrates

• Structural concrete
• Lightweight insulating concrete
• Gypsum decks
• Steel – minimum 22 gauge
• Wood (plywood or OSB)
• SBS-modified base sheets
• Existing modified bitumen or smooth built-up roof (BUR)

Compatible Insulation/Coverboards

• Poluisocyanurate – paper face and coated glass
• High density wood fiber
• Approved gypsum boards
• Securock®

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Source: Soprema