Ice dams and wind-driven rain remain two of the most common sources of roof leaks in cold climates. The building industry has long relied on self-adhered ice barrier membranes at eaves, valleys, and penetrations to create a watertight seal beneath the primary roof covering. Among the options available to builders and roofers, Grace Select Ice and Water Shield stands out as a cost-effective alternative to the premium-grade original Grace Ice and Water Shield. This self-adhered membrane delivers reliable protection at a price point that competes directly with traditional granular ice barrier sheets, making it an attractive option for production roofing and value-engineered projects. For a broader overview of how this product fits into the wider material landscape, see our guide on choosing roofing materials for cost and performance.
Product Overview and Composition of Grace Select Ice Barrier
Grace Select is a 25-mil-thick, self-adhered composite membrane manufactured by GCP Applied Technologies, the successor to W.R. Grace’s construction products division. It consists of a rubberized asphalt compound laminated to a polyethylene film top surface and protected by a release film on the adhesive side. The membrane is designed to be applied directly to the roof deck at vulnerable areas where water infiltration is most likely to occur, forming a permanent waterproof seal that prevents ice dam damage and wind-driven rain penetration.
Key Characteristics
- Thickness: 25 mils (0.025 inches), compared to the original Grace Ice and Water Shield at 40 mils or the premium Grace HT at 60 mils
- Adhesive system: Rubberized asphalt formulated for aggressive bonding to plywood and OSB roof decks, even at moderate temperatures
- Top surface: Smooth polyethylene film that provides a slip-resistant walking surface during installation
- Release liner: Embossed film that peels away cleanly without tearing, even at temperatures near the application limit
- Roll dimensions: Available in 36-inch-wide rolls in various lengths, typically 33.3 feet or 66.7 feet
- Coverage: One square (100 square feet) per roll for the standard size
How It Differs from the Original Grace Ice and Water Shield
The most practical difference between Grace Select and the original Grace Ice and Water Shield is thickness and price. The original product at 40 mils provides a heavier membrane with greater puncture resistance, making it the preferred choice for roofs with heavy foot traffic during installation or complex flashing details. Grace Select, at 25 mils, offers adequate protection for standard residential roof applications at a lower material cost. For most residential roof eaves in climate zones requiring ice barrier protection under IRC Section R905.1.2, the 25-mil membrane provides sufficient longevity and sealing performance. The selection between the two often comes down to the installer’s preference for puncture resistance versus budget considerations.
Another distinction is the surface texture. Grace Select has a smooth polyethylene surface, while some granular ice barrier sheets offer a textured walking surface. The smooth surface of Grace Select provides less slip resistance on steep slopes, but it also allows shingles to lie flatter over the membrane, reducing the telegraphing of surface irregularities through the finished roof.
Grace Select vs. Granular Ice Barrier Sheets
| Property | Grace Select (Self-Adhered) | Granular Ice Barrier Sheets |
|---|---|---|
| Thickness | 25 mils | 20 to 30 mils typically |
| Surface finish | Smooth polyethylene | Granular or sanded texture |
| Adhesion method | Peel-and-stick, rubberized asphalt | Peel-and-stick or torch-applied |
| Walkability during installation | Fair to good | Good to excellent (textured grip) |
| Cold-temperature application limit | Down to 25 degrees Fahrenheit | Varies by product, 20 to 40 degrees Fahrenheit |
| Puncture resistance | Moderate | Moderate to high depending on specification |
| Price point | Mid-range, competitive with granular | Low to mid-range |
| UV exposure limit | Up to 30 days | Up to 30 days typically |
Code Requirements and Application Zones for Ice Barrier Membrane
Building codes specify where self-adhered ice barrier membranes must be installed, and understanding these requirements helps builders use the material efficiently without over-application or code violations.
Code-Required Locations
The International Residential Code (IRC) mandates ice barrier protection in regions where the average daily temperature in January is 25 degrees Fahrenheit or lower. The membrane must extend from the eave edge up the roof slope to a point at least 24 inches beyond the interior wall line of the building. This typically places the membrane at least 6 feet up the roof slope from the eave edge, but the exact distance varies with roof pitch and insulation levels. Steeper roofs shed water faster and may require less extension, while low-slope roofs benefit from additional coverage.
Additional Application Zones Beyond Code Minimums
- Valleys: Ice barrier membrane installed 12 to 24 inches on each side of the valley centerline provides secondary protection against water migration beneath shingles during ice dam events
- Chimney and pipe penetrations: Wrapping flashings with self-adhered membrane at the base of penetrations prevents water tracking into the deck
- Dormer walls and roof-to-wall intersections: These transition zones are prime locations for ice dams to push water up under shingles and into the wall assembly
- Skylight curbs: Applying membrane around the curb perimeter before flashing creates a continuous watertight seal at this common leak point
- Roof ridges and hips: In severe ice dam regions, some builders extend membrane to the ridge for full coverage as a best practice
For a deeper comparison of underlayment types and their applications across different roof configurations, refer to our article on choosing between felt paper and synthetic roof underlayment.
Installation Best Practices for Self-Adhered Ice Barrier
Proper installation determines whether an ice barrier membrane performs as intended. The peel-and-stick application method is straightforward, but several details make the difference between a reliable seal and a future leak.
Surface Preparation
The roof deck must be clean, dry, and free of dust, oil, or frost before application. Plywood and OSB decks should be fully nailed and inspected for protruding fasteners that could puncture the membrane. Any damaged decking must be replaced before the membrane goes down. The ideal application temperature is above 40 degrees Fahrenheit. Below this threshold, the adhesive becomes stiff and may not bond effectively without additional measures such as using a roller or warming the membrane. A primer may be required on certain deck surfaces or in cold conditions.
Application Sequence
- Start at the eave edge: Align the first course parallel to the fascia, allowing the membrane to overhang the drip edge by approximately 1/4 inch so water runs cleanly into the gutter
- Peel the release liner: Remove approximately 12 to 18 inches of liner at a time, positioning the membrane before full adhesion to avoid repositioning
- Press firmly: Use a hand roller or a stiff broom to ensure full contact across the entire surface, paying special attention to edges and overlaps
- Overlap succeeding courses: Lap each subsequent course 4 to 6 inches over the previous one, following the manufacturer’s instructions for the specific product variant
- Roll all seams: Apply pressure to all lap joints with a J-roller to guarantee watertight adhesion at overlaps
- Work wrinkles carefully: If wrinkles form during application, slit them with a utility knife, apply a patch of membrane, and roll the repair area firmly
Cold-Weather Installation Tips
- Store membrane rolls in a heated space overnight before application to keep the adhesive flexible
- Use a propane torch or heat gun on low setting to warm the substrate and adhesive briefly when temperatures fall below 40 degrees Fahrenheit
- Apply extra rolling pressure to ensure bond development in cold conditions, using a weighted roller if available
- Limit exposed installation time in freezing weather to prevent condensation from forming on the cold substrate
- For warm-weather applications, consider Grace Ice and Water Shield HT, a high-temperature variant designed to resist softening in hot conditions
The surface preparation and rolling techniques for ice barrier membrane share many similarities with flashing tape installation. Our detailed guide on the right way to apply flashing tape covers the same principles of aggressive surface prep and uniform pressure for lasting adhesion.
Integrating Ice Barrier with Flashing, Valleys, and Roof Transitions
Ice barrier membrane does not replace flashing but works alongside it to create a comprehensive water management system. Proper integration at valleys, chimneys, and sidewalls is essential for leak-free performance.
Valley Flashing and Ice Barrier Coordination
In roof valleys, the ice barrier membrane serves as a secondary defense beneath the metal valley flashing. The membrane should extend 12 to 24 inches past the valley centerline on both sides, applied before the metal flashing is installed. This creates a redundant waterproof layer that captures any water migrating beneath the valley flashing during an ice dam event. For detailed methods on fabricating and installing custom valley flashing, see our article on mastering W-shaped valley flashing techniques.
Critical Flashing Transitions
Several transition points require careful coordination between the ice barrier membrane and the flashings to maintain continuity of the waterproof layer:
- Eave edge: The drip edge metal should be installed before the ice barrier in most cases, with the membrane lapping over the top flange. Some roofers prefer installing the membrane first and setting the drip edge over it; both methods work when properly detailed with sealant at the intersection
- Step flashing at sidewalls: At roof-to-wall intersections, the ice barrier should extend up the wall at least 8 inches, with step flashing woven into the shingle and membrane layers for a continuous water shed
- Pipe boot flashings: The membrane should be applied over the roof deck, the boot flange set in a bead of polyurethane sealant, and the boot nailed through the membrane with fasteners sealed individually
- Chimney cricket and saddles: Ice barrier should cover the entire cricket area, extending up the chimney sides before counterflashing is installed to prevent water entry behind the masonry
Drying-in the Roof Deck During Construction
One advantage of self-adhered ice barrier membrane is that it can serve as a temporary dry-in during construction. Grace Select rated for up to 30 days of UV exposure allows roofers to install the membrane at the eaves and valleys during the decking phase, providing immediate weather protection while the rest of the roof is completed. This sequencing flexibility helps keep the interior dry during multi-week roofing projects, particularly in climates where rain can arrive unexpectedly.
After the ice barrier is in place, the remainder of the roof underlayment is installed over the field of the roof, followed by the shingles or standing seam panels. The result is a layered system where each component handles a specific water management function, with the ice barrier acting as the last line of defense at the most vulnerable points. Grace Select offers builders a proven self-adhered solution that meets code requirements, fits within project budgets, and delivers the long-term performance that homeowners expect from a properly constructed roof assembly.