Hydraguard Dual Pro

High Temperature Metal & Tile Underlayment


Dual Pro is a self-adhered waterproofing membrane. The advanced modified asphalt compounds are reinforced with a fiberglass mat. Dual Pro also has a high strength polyester fabric on the upper surface making it a high temperature underlayment ideally suited for metal roof and tile applications.

Dual Pro underlayments are manufactured with an aggressive self-adhesive bottom compound, using a patented Dual-Compound Technology, protected by an easily removed split-release film. Dual Pro also features SEALLap®, a patented factory applied adhesive treatment that provides improved product performance at the overlaps.


  • Underlayment in metal roof and tile applications
  • High temperature underlayment environments up to 250° F
  • Designed as effective reinforcement for perimeter and flashing details

Feature and Benefits

  • Proprietary asphalt compound and fiberglass mat for exceptional dimensional stability
  • Non-wicking polyester reinforced surface engineered for superior slip resistance
  • Approved exposure rating to 90 days (or as limited by local building codes)

Technical Description

Test MethodPropertyTypical Value
ASTM D5147Maximum Load, Longitudinal and Transverse, min, kN/m (lbf/in.)4.4 (25)
ASTM D5147Elongation at break, min of modified bitumen portion (%) 10
ASTM D5147Tear Resistance, Longitudinal and Transverse, min, N (lbf)89 (20)
ASTM E96Moisture Vapor Permeability, max, perms0.1
ASTM D1970Adhesion to Plywood @ 40F, min, lbf/ft width2.0
ASTM D1970Adhesion to Plywood @ 75F, min, lbf/ft width12.0
ASTM D1970Sealability around nailpass
ASTM D1970Waterproof integrity after low temp flexibilitypass
ASTM D1970Waterproof integrity of lap seampass
ASTM D1970Slip Resistancepass

Application Instructions

  • Hydraguard underlayments may be directly applied to certain wood decks as allowed by the AHJ (Authority Having Jurisdiction).
  • Cut the Hydraguard self-adhered membrane to a suitable length based on the project and application conditions.
  • Unroll the membrane and allow it to lay flat and relax prior to application. After the membrane has relaxed, align it with the lowest edge of the roof.
  • Fold the aligned membrane in half to expose one side of the split release film.
  • Peel the release film at a 90° angle, in a constant motion, while keeping the weight on the outer edges as you progress. Press the membrane into place with firm and uniform pressure from the center to the outer edges.
  • Repeat previous step with the remaining half of the roll and release liner.
  • Always ensure that the membrane is applied to cover the highest point of “ice damming”.
  • Be sure to follow all local building code recommendations and requirements with regards to the width of ice dam materials.
  • All Hydraguard underlayments should be back-nailed in the selvage edge seam. Use 11 gauge ring shank type nails with minimum 7⁄8" head or 3⁄8" head driven through a 1" metal disk (refer to local building codes). Cover all nails with the selvage overlap of the next sheet.
  • Position and install the next sheet by overlapping the side laps at a 3" minimum. Overlap and cut the end laps a minimum of 6". Repeat installation steps.
  • Use Polyglass PolyPlus® 50 Premium MB Flashing Cement to seal all end laps, hip and ridge details, and any fabric-to-fabric splices, patches or details. Alternative ASTM D4586 and ASTM D3409 compliant flashing cements or approved materials may also be used.
  • Roll entire roof surface with a 50 lb. weighted roller to ensure complete contact to the underlying surface. Firmly roll the seams and laps with a hand roller to ensure full adhesion. Alternative measures may be required for steeper roof designs.
  • Six (6) concrete tiles per stack are allowed when loading tile on the underlayment(tile loading graphic seen on packaging)
  • Loading battens or other appropriate restraint devices are to be used on all projects for loading of roof coverings and it is recommended even at slopes lower than 6/12 if the risk of sliding is suspected.
  • Minimum time after membrane installation and before loading of roof tile is 48 hours.
  • Hydraguard underlayments are not designed for use at exposed application locations such as; crickets, exposed valleys and exposed areas at walls.
  • Manufacturer recommends that the installer follow good roofing practices, application procedures as outlined in the NRCA, ARMA and other published practices.
  • For applications involving non-ventilated attics or sheathing with radiant barriers, an anchor sheet is recommended to allow venting and prevent the creation of a double vapor barrier condition which can lead to issues related to underlayment wrinkling after installation and heat aging of the roof covering.