[GCP] GRACE Ice & Water Shield

Product Description

GRACE ICE & WATER SHIELD® has been the premier self-adhesive underlayment product used in domestic roof protection under shingles for more than 30 years. It has performed in the critical areas under the most severe climatic conditions to protect against wind-driven rain and the effects of ice dam build-up beneath the shingles.

Because of the unique properties of Grace Ice & Water Shield, these benefits are also applicable in its use under a wide range of metal roofing materials, on low and high slope designs.

Grace Ice & Water Shield membrane is composed of two waterproofing materials — an aggressive rubberised asphalt adhesive backed by a layer of high density, cross-laminated polyethylene. The rubberised asphalt surface is backed with a release paper that protects the adhesive quality. During application, the release paper is removed allowing the compound to bond tightly to the plywood deck. The membrane is supplied in 20m rolls, 1m in width.

Product Advantages & Features

• Easy to handle and apply
  The self-adhesive membrane bonds firmly to the roof deck without heat or special adhesives.

• Foldless release paper
  The foldless release paper provides multiple performance enhancements: fewer edge catches, 180° pull-back, ease of membrane cutting (single cuts) and membrane positioning, quicker “one-man installs” resulting in an easier, more productive release.

• Seals around nails
  The rubberised asphalt layer in Grace Ice & Water Shield seals around roofing nails, resisting leakage caused by water back-up behind ice dams, or from wind-driven rain.

• Dual barrier protection
  Rubberised asphalt and polyethylene are combined to form two waterproofing barriers providing maximum protection.

• Membrane will not crack, dry out or rot
  Grace Ice & Water Shield resists attacks from fungus and bacteria; maintains its integrity for long-lasting protection.

• Protects under all standard sloped roof coverings
  Grace Ice & Water Shield protects under slate, tile, cedar shakes or metal, as well as under conventional asphalt shingles.

• Slip-resistant surface
  Grace Ice & Water Shield has a slip-resistant, embossed surface to maximise traction and safety for applicators.

• Proven track record
  Grace Ice & Water Shield is the name brand in roofing underlayments with a 30-year track record of protecting roofs from ice dams and wind-driven rain.

• Re-roofable
  Unlike some granular surfaced membranes, Grace Ice & Water Shield will not adhere to the underside of the exposed roof covering. It can be applied over the old underlayment (except over BASIK®) in retrofit applications, making reroofing easier, less costly (since there is no need for removing the existing underlayment), more durable and environmentally friendly (as the structural deck remains intact avoiding the need to purchase additional wood decking).

• GCP technical support
  Grace Ice & Water Shield is backed by a team of local technical support personnel that help ensure every application goes smoothly.

 * Nominal thickness refers to the thickness of the membrane without release liner.
 ** Typical test values may represent average values from samples tested. Test methods noted may be modified. The test is run at a rate of 50mm per minute

Installation Procedure

Before installing Grace Ice & Water Shield, ensure the surface is clean, dry, and structurally sound. Suitable decking materials include plywood, wood composition, wood planks, metal, concrete, or gypsum sheathing. Remove all dust, dirt, loose nails, and remnants of previous roofing materials. Any protrusions on the deck surface must be removed, and the deck itself should have no voids, damaged sections, or unsupported areas. Wood planks should be tightly butted together, and any areas in need of repair must be addressed before applying the membrane.

For certain surfaces, priming is required to ensure proper adhesion. Concrete, masonry surfaces, and DENSGLASS GOLD® must be primed using PERM-A-BARRIER® WB Primer. Wood composition and gypsum sheathing should also be primed if adhesion is found to be marginal, as outlined in Technical Letter 12 regarding the use of this product on OSB roof sheathing. Apply the primer at a rate of 6 to 8 square meters per liter. Other suitable surfaces do not require priming, provided they are clean and dry.

Grace Ice & Water Shield should be installed in fair weather conditions when the air, roof deck, and membrane are all at temperatures of 5°C or higher. The roofing material itself should also be applied at temperatures above 5°C. The membrane can be applied along eaves, in valleys, and in areas prone to severe ice damming. For complete protection against wind-driven rain, the membrane can be installed across the entire roof deck. In retrofit applications, a new layer of Grace Ice & Water Shield can be applied directly over an existing underlayment, following the standard installation process.

To begin installation, cut the membrane into lengths of 3 to 5 meters and reroll loosely. Peel back 300 to 600 millimeters of the release liner to align the membrane, then continue peeling and pressing it into place with firm hand pressure. Side laps should be a minimum of 90 millimeters, and end laps should be at least 150 millimeters. For valley and ridge applications, center the sheet over the valley or ridge, peel back the liner, drape it into position, and press it firmly from the center outward and from the bottom upward.

Alternatively, you may choose to install the membrane by starting with a full roll. Unroll 1 to 2 meters of membrane while keeping the release liner in place. Align the membrane with the intended direction of installation and carefully cut the release liner across the top, being cautious not to damage the membrane itself. Peel back approximately 150 millimeters of the release liner in the opposite direction to expose the black adhesive layer. Holding the liner with one hand, pull the roll along the deck while the membrane adheres behind it. Use your other hand to press down on the membrane to secure it. Stop regularly to press the membrane firmly into place. Once you've unrolled the full length, return to the beginning, reroll, and pull off any remaining release liner to complete the installation.

For overlapping subsequent rows, align the membrane with the dashed guideline printed on the surface to maintain a consistent 90 millimeter side lap.

Consistent with good roofing practices, the membrane must be installed in a way that ensures all laps shed water. Always work from the lowest point of the roof upward. Begin by applying the membrane in valleys before continuing along the eaves. Once the membrane is in place along the eaves, continue the installation up the slope of the roof. The membrane can be installed either vertically or horizontally, depending on the roof design and installer preference.

For best results when fastening shingles over the membrane, use smooth-shank, electro-plated galvanized nails. Hand-nailing is generally recommended, as it tends to provide a better seal than power-actuated nailing systems. On steep slopes or during extreme weather conditions—whether hot or cold—if it becomes necessary to nail the membrane itself, use a back-nailing technique and ensure that the nails are covered by overlapping them with the next sheet.

The membrane should be extended on the roof deck above the highest expected level of water backup from ice dams. Similarly, it should be extended above the highest expected accumulation of snow and ice on vertical wall sheathing, such as on dormers or vertical front walls, to ensure comprehensive ice dam protection. In critical areas, consider applying a double layer of the membrane for enhanced durability.

This membrane is not compatible with EPDM or TPO roofing materials. For tie-ins with these types of roofing systems, use Grace Ultra instead, as specified in Technical Letter 5 on chemical compatibility. Additionally, the membrane is not compatible with polysulfides, flexible PVC, or surfaces containing high concentrations of resin (pitch). For further information on compatible materials, refer to Technical Letter 5.

Precautions and Limitations

• Slippery when wet or covered by frost.

• Always wear fall protection when working on a roof deck, in line with good roofing practices.

• Release liners are slippery — remove them from the work area immediately after membrane application.

• Do not leave the membrane permanently exposed to sunlight — cover within 90 days.

• Install metal drip edges or wood starter shingles over the membrane.

• Do not fold the membrane over the roof edge unless protected by a drip edge, gutter, or other flashing material.

• Do not install on chamfered edges of wood planks.

• Do not install directly on old roof coverings.

• Certain applications are not suitable in hot desert climates — consult your local GCP representative.

• Check with the metal roofing manufacturer for special requirements when used under metal roofs.

• Do not install directly under roof coverings that are especially sensitive to corrosion (e.g., zinc) without proper ventilation.

• Do not install under copper, COR-TEN®, or zinc roofs in high altitudes — use Grace Ultra instead.

• Provide adequate insulation and ventilation to reduce ice dams and minimize condensation.

• Grace Ice & Water Shield is an air and vapour barrier.

• Repair holes, fishmouths, tears, or damage with a round patch extending 150 mm beyond the damaged area in all directions.

• Patch any holes left by removed fasteners — the membrane does not self-seal around open penetrations.

• Do not install fasteners through the membrane over unsupported structural deck areas (e.g., between panel joints).

• Do not apply the membrane in areas where it may be exposed to interior living spaces, due to its asphaltic odour — refer to product literature for complete information.

Code Compliance

Grace Ice & Water Shield meets the following standards:

• Underwriters Laboratories Inc.

  • Class A fire classification under fiberglass shingles

  • Class C fire classification under organic felt shingles
    (per ASTM E108/UL 790)

• Underwriters Laboratories Inc. Classified Sheathing Material Fire Resistance Classification with Roof Designs:
  P225, P227, P230, P237, P259, P508, P510, P512, P514, P701, P711, P717, P722, P723, P732, P734, P736, P742, P803, P814, P818, P824

• Miami-Dade County Code Report NOA 09-0107.08

• Canadian Construction Materials Centre (CCMC) 12693-R

• U.S. Department of Housing and Urban Development (HUD) Materials Release 1068g

• City of Los Angeles RR 25330

• Florida State Approval Report No. FL298-R3

• International Code Council Evaluation Services (ICC-ES) Report No. ESR-1677