Grace Ultra is a high-performance, self-adhered roofing underlayment designed for use in extreme temperature conditions and high-risk areas such as valleys, eaves, and around roof penetrations. Its unique formulation of butyl rubber-based adhesive and cross-laminated polyethylene ensures durability, heat resistance, and water protection. For U.S. consumers, contractors, and DIY enthusiasts, proper installation is critical to achieving the full benefits of this roofing underlayment. This article provides a detailed guide based on official manufacturer instructions, specifications, and application procedures to ensure correct and effective use of Grace Ultra.
Product Overview and Key Features
Grace Ultra is a self-adhered roofing underlayment designed to serve as a protective layer beneath primary roofing materials. It is composed of two main components:
- Butyl rubber-based adhesive: This ensures strong adhesion to the roof deck and high temperature stability.
- Cross-laminated polyethylene: This provides structural integrity and durability.
The product is 0.76mm thick and measures 864mm in width, with each roll covering 18.4 square meters. These dimensions make it both flexible and easy to handle during installation. The underlayment is designed to resist temperatures up to 300°F (149°C), making it ideal for high-temperature applications such as those involving copper, zinc, or COR-TEN® metal roofing systems.
Grace Ultra also offers key advantages for users and installers:
- Self-sealing: The membrane meets key building code standards for nail sealability of self-adhered roofing underlayments.
- Heat resistance: It is specially formulated to resist temperatures up to 300°F without degradation.
- Chemical resistance: It is compatible with low slope roofing materials such as EPDM and TPO.
- Reroofable: The underlayment does not adhere to the underside of exposed roofing materials, facilitating easier re-roofing.
- Slip-resistant surface: It provides better traction, enhancing safety during installation.
These features make Grace Ultra suitable for both new construction and retrofit applications, especially in regions prone to ice dams, wind-driven rain, or high-temperature conditions.
Surface Preparation and Installation Requirements
Before applying Grace Ultra, the surface must be properly prepared to ensure effective adhesion and long-term performance. The following steps are recommended:
1. Appropriate Substrate
Grace Ultra can be installed directly on a variety of structural deck materials, including:
- Plywood
- Wood composition
- Wood plank
- Metal
- Concrete
- Gypsum sheathing
For substrates not listed, it is advised to consult with a local GCP Applied Technologies representative to confirm compatibility.
2. Surface Cleanliness and Condition
The surface must be clean, dry, and free of debris such as dust, dirt, loose nails, and old roofing materials. Protrusions from the deck area must be removed. The deck should also be free of voids, damaged, or unsupported areas. Any damaged sections should be repaired before installation.
3. Primaing the Surface
Priming is required for certain surfaces to enhance adhesion. Specifically:
- Concrete and masonry surfaces, as well as DENSGLASS GOLD, should be primed with PERM-A-BARRIER® WB Primer.
- Wood composition and gypsum sheathing should be primed with Perm-A-Barrier WB Primer if adhesion is marginal. For more information on OSB compatibility, refer to Technical Letter 12.
The primer should be applied at a rate of 6 to 8 square meters per liter. Priming is not required for other suitable surfaces, provided they are clean and dry.
4. Weather and Temperature Conditions
Installation should occur in fair weather when the air, roof deck, and membrane are at or above 5°C (41°F). This ensures proper adhesion and performance. The roof covering material should also be applied at temperatures of 5°C or higher.
Installation Procedures
Grace Ultra can be installed using several methods, depending on the specific application and installer preference. The key steps include:
1. Membrane Preparation
The membrane should be cut into lengths of 3 to 5 meters and rerolled loosely. The end of the roll should be tacked or secured with a nail to prevent shifting during installation.
The release liner should be peeled back by 300 to 600mm to allow for alignment of the membrane on the roof deck. Once aligned, the release liner should be peeled further, and the membrane pressed into place with heavy hand pressure.
2. Lapping Techniques
Laps are critical for ensuring water resistance and durability. The following lap requirements should be observed:
- Side laps: Minimum of 90mm
- End laps: Minimum of 150mm
For valley and ridge applications, the membrane should be centered over the valley or ridge, draped, and pressed into place. Work should be done from the center of the valley or ridge outward in each direction, starting at the low point and working up the roof.
An alternative method involves unrolling a 1 to 2m piece of membrane with the release liner still in place. The membrane should be aligned and rolled in the intended direction of application. The release liner should then be cut carefully in the cross direction without cutting the membrane. Approximately 150mm of the release liner should then be peeled back in the opposite direction of the intended application, exposing the adhesive surface. The membrane is then held in place by the release liner and pulled along the roof deck.
3. Placement of Metal Drip Edges and Starter Shingles
To protect the membrane from exposure to sunlight and to maintain a secure installation, metal drip edges or wood starter shingles should be placed over the membrane. This is especially important for eave applications. For more information, refer to Technical Letter 15.
Drip edges should not be folded over the roof edge unless the edge is protected by a drip edge, gutter, or other flashing material. The membrane should not be installed on the chamfered edges of wood plank or directly on old roof coverings.
4. Handling and Safety
Several key handling and safety precautions should be followed:
- Do not leave the membrane permanently exposed to sunlight. The maximum recommended exposure is 60 days.
- Do not install fasteners through the membrane over unsupported areas of the structural deck, such as over the joints between adjacent structural panels.
- If fasteners are removed and leave holes in the membrane, they must be patched. The membrane may not self-seal open fastener penetrations.
- Repair any holes, fishmouths, tears, or damage to the membrane with a round patch that extends past the damaged area by 150mm in all directions.
Application in High-Temperature and Special Situations
Grace Ultra is specifically formulated for high-temperature applications, making it ideal for use under metal roofing systems that may conduct significant heat, such as those using copper, zinc, or COR-TEN® panels. These materials can expose the underlayment to temperatures that could degrade less heat-resistant products. Grace Ultra’s formulation ensures it can withstand these conditions without compromising performance.
When used under metal roofing systems, it is important to check with the manufacturer of the metal roofing system for any special requirements. Certain metal types, such as zinc, may require additional ventilation to prevent corrosion. Since Grace Ultra is a vapor barrier, proper insulation and ventilation are essential to reduce the risk of ice dams and condensation.
For retrofit applications, a new layer of Grace Ultra can be applied directly over the old underlayment, following the standard membrane application procedure. This is particularly useful in regions where ice dams or wind-driven rain are common.
Ice Dam and Wind-Driven Rain Protection
Grace Ultra is particularly effective in protecting against ice dams and wind-driven rain. Ice dams form when snow melts on a roof and refreezes at the eaves, causing water to back up and potentially leak into the structure. Grace Ultra should be applied to a point on the roof deck above the highest expected ice dam. The exact height of the ice dam depends on several factors, including:
- Climate: Annual snowfall and temperature fluctuations
- Roof slope and overhang
- Valleys and roof design
- Insulation and ventilation of the structure
- Sun exposure vs. shade
Local building codes should be consulted for specific requirements, as these can vary by region. In critical areas—such as along the eaves, in valleys, or around chimneys and skylights—a double layer of membrane is recommended in climates where severe ice dams are anticipated.
For wind-driven rain protection, full coverage with Grace Ultra is recommended. This helps prevent rain from being driven under the roof covering during storms. Since Grace Ultra is a vapor barrier, proper ventilation is essential in full coverage applications to prevent condensation buildup.
Limitations and Restrictions
Several installation restrictions should be noted to ensure proper use of Grace Ultra:
- Avoid permanent exposure to sunlight: The maximum recommended exposure is 60 days.
- Avoid installation on unsupported deck areas: Fasteners should not be installed through the membrane over joints or unsupported areas.
- Avoid installation on old roof coverings: Grace Ultra should not be applied directly on old roof materials.
- Avoid installation on chamfered edges of wood plank: This can compromise adhesion and integrity.
- Special handling for metal roofing systems: Consult with the metal roofing manufacturer for specific requirements, especially when using sensitive materials like zinc.
- Proper ventilation and insulation: These are essential for reducing ice dams and condensation.
Conclusion
Grace Ultra is a high-performance roofing underlayment designed for use in extreme temperature conditions and high-risk areas such as valleys, eaves, and around roof penetrations. Its unique butyl rubber-based adhesive and cross-laminated polyethylene formulation provide superior heat resistance, self-sealing properties, and chemical compatibility with a range of roofing materials. When installed correctly, Grace Ultra offers effective protection against ice dams, wind-driven rain, and other water intrusion risks.
Installation requires careful surface preparation, adherence to temperature and weather conditions, and proper lapping and placement techniques. Special considerations must be taken for high-temperature applications, retrofit projects, and metal roofing systems. By following the manufacturer’s guidelines and local building codes, users can ensure optimal performance and longevity from their Grace Ultra underlayment.