Grace Ice & Water Shield® HT high temperature self-adhered roofing underlayment is a premier membrane designed to deliver premium in-place performance for high temperature applications. It is composed of two waterproofing materials—an innovative and proprietary rubberized asphalt adhesive combined with a high performance polymeric film with UV barrier properties. The rubberized asphalt surface is backed with a foldless release paper that protects its adhesive quality. During application, the release paper is easily removed, allowing the rubberized asphalt to bond tightly to the roof deck. The Ripcord® embedded in the adhesive provides the applicator a “split release on demand” feature, making it easier to apply in detail areas.
Features & Benefits
Today’s sloped roof designs utilize more insulation and incorporate long-lasting roof coverings that tend to have lengthy construction cycles. The many variables that contribute to roof top temperatures; insulation, facing, pitch, color, etc., make it difficult to predict what kind of heat profile the roof top will experience. Choosing an underlayment that will perform under all of these demanding conditions is essential to a successful roof design.
Grace Ice & Water Shield® HT underlayment was specifically designed to meet the challenge of these high-temperature applications. It is an environmentally conscious solution that provides both confidence and design flexibility.
High temperature resistance — Designed to withstand high temperature applications, up to 260°F (127°C).
Seals around fasteners — The rubberized asphalt layer in Grace Ice & Water Shield® HT membrane seals around roofing nails and other fasteners, resisting leakage caused by water back-up behind ice dams or wind-driven rain.
Superior adhesion — The self-adhered membrane bonds firmly to the roof deck without supplemental heat or special adhesives.
Extended exposure — Can be left exposed for up to 120 days before installing final roof covering
Watertight laps — Membrane easily forms water-tight overlaps without special treatment.
Protects under all standard sloped roof coverings — Grace Ice & Water Shield® HT underlayment protects under standing seam metal, slate, tile, cedar shakes, metal and conventional asphalt shingles.
Slip resistant surface — Grace Ice & Water Shield® HT underlayment has a slip resistant embossed surface to maximize traction and improve safety.
Ripcord — Split Release on demand feature makes Grace Ice & Water Shield® HT underlayment easier to apply. Faster application of the membrane in the straight-aways, as well as ease of membrane positioning in detail areas (valleys, around dormers, etc.).
Membrane will not crack, dry out or rot — Grace Ice & Water Shield® HT membrane resists attacks from fungus and bacteria; maintains its integrity for long lasting protection.
Local technical support — Grace Ice & Water Shield® HT roofing underlayment is backed by a team of local technical support personnel that help ensure every application goes smoothly.
Guidelines for Use
Grace Ice & Water Shield® HT roofing membrane is used as an underlayment for sloped roofs to resist water penetration due to water back-up behind ice dams or wind-driven rain. Grace Ice & Water Shield® HT underlayment also offers leak protection in trouble prone spots like valleys, skylights, protrusions and other flashing areas.
Grace Ice & Water Shield® HT roofing underlayment should be used in conjunction with roof designs that minimize ice dam formation. In cold climates, it is particularly important to provide proper insulation and ventilation to reduce the size of ice dams and to avoid interior condensation. Cathedral ceilings must include ventilation between rafters to allow for air flow to a ridge vent. Well ventilated cold roof designs are particularly important in alpine regions to reduce the size of ice dams which could contribute to structural damage.
Several variables will influence the height of ice dams and the membrane coverage required.
- Climate — The annual snow fall will affect the amount of membrane needed.
- Slope — On a low slope, ice dams will extend farther inward from the roof edge.
- Overhang — A wide overhang will require more membrane to reach the appropriate point on the roof.
- Insulation and ventilation — A very well insulated building with a cold, well ventilated attic will have smaller ice dams.
- Valleys — Any valleys formed by projections such as dormers or roof direction changes are likely to trap more snow and cause larger ice dams.
- Exposure — A northern exposure or shaded areas will generally contribute to larger ice dams. While gutters may make it easier for an ice dam to start, large dams can occur on roofs with no gutters. Removing snow from a roof edge or installing heat cables may not prevent ice dam formation, but may shift the location of the ice dam. Under certain conditions, a dam can form at the edge of the remaining snow. Local building codes should be consulted for specific requirements.
Install Grace Ice & Water Shield® HT roofing underlayment directly on a clean, dry, continuous structural deck. Some suitable deck materials include plywood, wood composition, wood plank, metal, concrete, and gypsum sheathing. Prior to membrane application remove dust, dirt, loose nails, and old roofing materials. Protrusions from the deck area must be removed. Decks shall have no voids, damaged, or unsupported areas. Wood planks should be closely butted together. Repair deck areas as needed before installing the membrane. (Refer to Tech Letter #5, Chemical Compatibility, when installing over wood plank decks).
Prime concrete, masonry surfaces and DensGlass Gold® with Perm-A-Barrier® WB Primer. Prime wood composition and gypsum sheathing with Perm-A-Barrier® WB Primer if adhesion is found to be marginal (refer to Technical Letter 12, Use on Oriented Strand Board (OSB) Roof Sheathing). Apply Perm-A-Barrier® WB Primer at a rate of 250–350 ft2/gal (6–8 m2/L). Priming is not required for other suitable surfaces provided that they are clean and dry.
Precautions & Limitations
- Slippery when wet or covered by frost.
- Consistent with good roofing practice, always wear fall protection when working on a roof deck.
- Release liners are slippery. Remove from work area immediately after membrane application.
- Do not leave permanently exposed to sunlight. Cover within 120 days.
- Place metal drip edges or wood starter shingles over the membrane.
- Do not fold over the roof edge unless the edge is protected by a drip edge, gutter or other flashing material. •Do not install on the chamfered edges of wood plank.
- Do not install directly on old roof coverings.
- Check with the manufacturer of the metal roofing system for any special requirements when used under metal roofing. Do not install directly under roof coverings especially sensitive to corrosion, such as zinc, without providing proper ventilation.
- Do not install under copper, Cor-Ten® , or zinc metal roofing in high altitudes. These roofs can reach extremely high temperatures due to the low reflectivity, high absorption, and high conductivity of the metals. Use Grace Ultra™ butyl-based underlayment for these roof types. Contact your GCP Applied Technologies sales representative for assistance choosing the best product for your application.
- Provide proper roof insulation and ventilation to help reduce ice dams and to minimize condensation. Grace Ice & Water Shield® HT underlayment is an air and vapor barrier.
- Repair holes, fishmouths, tears, and damage to membrane with a round patch of membrane extending past the damaged area 6 in. (150 mm) in all directions. If fasteners are removed leaving holes in the membrane, they must be patched. The membrane may not self-seal open fastener penetrations.
- Do not install fasteners through the membrane over unsupported areas of the structural deck, such as over the joints between adjacent structural panels.
- Due to its slight asphaltic odor, do not apply where the membrane is exposed to interior living space. Refer to product literature for more complete information.
- Not compatible with EPDM or TPO; use Grace Ultra® for tie-ins (refer to Technical Letter 5, Chemical Compatibility).
- Not compatible with polysulfides, flexible PVC, or high concentrations of resin (pitch) found in some wood plank decks. For more information, refer to Technical Letter 5.
Grace Ice & Water Shield® HT underlayment meets all key code performance requirements for self-adhered underlayments.
- Meets ASTM D1970
- ICC-ES ESR-3121 approval according to AC–48 Acceptance Criteria for Self-Adhered Underlayments to be used as an Ice Barrier
- Miami-Dade County Code Report NOA #15-0728.11
- Florida State Approval Report No. FL289-R3
- CCMC Approval No. 13671-L
- Underwriters Laboratories Inc. R13399- Class A fire classification under fiber-glass shingles and Class C 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
Apply Grace Ice & Water Shield® HT roofing underlayment in fair weather when the air, roof deck, and membrane are at temperatures of 40°F (5°C) or higher. Apply roof covering material at temperatures of 40°F (5°C) or higher.
Cut the membrane into 10–15 ft (3–5 m) lengths and reroll loosely. Peel back 1–2 ft (300–600 mm) of release liner, align the membrane, and continue to peel the release liner from the membrane. Press the membrane in place with heavy hand pressure.
Side laps must be a minimum of 3.5 in. (90 mm) and end laps a minimum of 6 in. (150 mm). For valley and ridge application, peel the release liner, center the sheet over the valley or ridge, drape, and press it in place. Work from the center of the valley or ridge outward in each direction and start at the low point and work up the roof.
Alternatively, starting with a full roll of membrane, unroll a 3–6 ft (1–2 m) piece of membrane leaving the release liner in place. Align the membrane and roll in the intended direction of membrane application. Carefully cut the release liner on top of the roll in the cross direction being careful not to cut the membrane. Peel back about 6 in. (150 mm) of the release liner in the opposite direction of the intended membrane application exposing the black adhesive. Hold the release liner with one hand and pull the roll along the deck with the release liner, leaving the applied membrane behind. Use the other hand to apply pressure on the top of the roll. Stop frequently to press the membrane in place with heavy hand pressure. When finished with the roll go back to the beginning, reroll and pull the remaining release paper from the material, finishing the installation.
For successive membrane courses, align the edge of the release liner with the dashed line provided on the surface of the membrane to achieve the 3.5 in. (90 mm) side lap.
Consistent with good roofing practice, install the membrane such that all laps shed water. Always work from the low point to the high point of the roof. Apply the membrane in valleys before the membrane is applied to the eaves. Following placement along the eaves, continue application of the membrane up the roof. The membrane may be installed either vertically or horizontally.
Use smooth shank, electro-plated galvanized nails for fastening shingles to get the best seal. Hand nailing generally provides a better seal than power-activated nailing. If nailing of the membrane is necessary on steep slopes during hot or extreme cold weather, backnail and cover the nails by overlapping with the next sheet.
Extend the membrane on the roof deck above the highest expected level of water back-up from ice dams and above the highest expected level of snow and ice on the wall sheathing on vertical side walls (dormers) and vertical front walls for ice dam protection. Consider a double layer of membrane in critical areas, such as along the eaves or in valleys and in climates where severe ice dams are anticipated. Apply the membrane to the entire roof deck for wind-driven rain protection. Apply a new layer of Grace Ice & Water Shield® HT membrane directly over the old GCP selfadhered underlayment (except GCP granular underlayment) in retrofit applications following the standard membrane application procedure.
|Roll length||75 ft (22.9 m)||66.6 ft (20.2 m)|
|Roll width||36 in (914 mm)||36 in (914 mm)|
|Roll size||225 ft2 (20.9 m2)||200 ft2 (18.6 m2)|
|Packaging||Corrugated cartons||Corrugated cartons|
|Roll weight||61.4 lbs (27.9 kg)||56 lbs (25.4 kg)|
|Rolls per pallet||35||35|
|Thickness, membrane||40 mil (1.02 mm)||ASTM D3767 method A|
|Tensile strength, membrane||MD 25 lbf/in., CD 25 lbf/in.||ASTM D412 (Die C modified)|
|Elongation, membrane||250%||ASTM D412 (Die C modified)|
|Low temperature flexibility||Unaffected @ -20°F (-29°C)||ASTM D1970|
|Adhesion to plywood||3.0 lbs/in. width (525 N/m)||ASTM D903|
|Permeance (max)||0.05 Perms (2.9 ng/m2s P||ASTM E96|
|Material weight installed (max)||0.22 lb/ft2 (1.3 kg/m2)||ASTM D461|
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We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.
Grace Ice & Water Shield, Grace Ultra, Perm-A-Barrier, Ripcord are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.
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In Canada, GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6.
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Last Updated: 2018-12-12