Grace Common Questions (FAQ)

We've gathered the most commonly asked questions about Grace Building Products. If your question isn't answered here, you may also contact us with any questions you may have.

Common Questions

Are Grace underlayments chemically compatible with most roofing substrates?

Grace underlayment is recommended for use over wood substrates. They are compatible with acids, bases, salts, asphalts and dried, fully cured coal tar. Grace underlayments are not compatible with the following substances:

  • Creosote
  • Diesel Fuel/Gasoline/Oil
  • Hydrocarbon Solvents
  • Pentachlorophenol
  • Polysulfids
  • EPDM
  • Flexilbe PVC

What types of fasteners should I use to mechanically fasten Grace roofing underlayments?

Grace underlayments that are not self-adhered will require roofing nails or staples both having 1-inch diameter plastic/metal caps. Capped nails or staples may be either machine or hand applied. Nails or staples without caps cannot be used. The fasteners must be spaced at 8 inches on center on both sides and end laps in normal wind zones. In high wind zones or coastal applications, double the fastening to 4 inches on center. Ensure fastening at 24 inches on center down the middle of the roll in the field of the roof.

Why should I use flashing on my deck?

Water damage is the most common reason for deck replacement. Water that accumulates under the deck boards does not dry out easily. Grace Deck Protector self-adhered flashing provides protection for your deck joists from mold, dry rot, and decay saving you from costly repairs in the future. This flashing also protects from corrosion - by installing Vycor Deck Protector where the metal fasteners connect with the wood, the membrane creates a barrier between the copper (in wood) and the zinc (in metal).

How do I ensure proper air and vapor ventilation in my roof structures?

Grace roof underlayments are excellent air and vapor barriers. Proper roof ventilation and insulation should be left to a qualified design professional and should comply with all local building codes. Standard roofing practice is to use 0.093 square meters (1 square foot) of net free ventilation area per 14 square meters (150 square feet) of attic space, split evenly between ridge and soffit vents. Grace roof underlayments are not intended for use as an air and vapor barrier in above-grade wall assemblies.

How do I determine the necessary lengths required to properly install window flashing?

ASTM E2112-01* and AAMA 2400-02* recommend the use of a minimum 9" wide flashing membrane beyond the rough opening. Grace recommends a 12" wide flashing membrane for proper waterproofing of the window sill.

  • Sill Flashing: Rough Opening width + (2 x flashing width)
  • Jamb Flashing: Rough Opening height + (2 x flashing width) - 1 inch
  • Head Flashing: Rough Opening width + (2 x flashing width) + 2 inches

How do you use Grace Ripcord "Split-Release on Demand"?

First locate Ripcord at the center of the membrane. Next, create a notch in the release paper at mid-center. Pull back the release paper and extract Ripcord. Then, pull Ripcord, splitting the release paper in half.

Can Grace roofing underlayments and wall membranes be applied either horizontally or vertically?

Grace products that are self-adhering may be installed in both horizontal and vertical applications (Grace Vycor enV-S, Vycor Plus, Ice & Water Shield/HT, Roof Detail Membrane, Select, Vycor Deck Protector, Vycor Pro). Grace products that are mechanically fastened must be installed horizontally (Grace Tri-Flex 15 and Tri-Flex XT).

How long can Grace Roofing Underlayments be exposed before covering?

In general, the membrane should be covered with the final roof covering as soon as possible. However, Grace underlayments may be left exposed if necessary, to accommodate construction scheduling or weather problems. These are Grace the Underlayments Maximum Exposure Guidelines

What are the benefits of choosing Grace Vycor enV-S Self-Adhered Weather Resistive Barrier over other house wraps?

Grace Vycor enV-S achieved an air leakage rate seven times lower than the leading house wrap brands in all regions of the United States. Unlike mechanically attached house wraps, enV-S remains adhered to the substrate when exposed to harsh weather conditions. This self-adhering house wrap eliminates the cost of purchasing fasteners and there is no need to tape the seams as it adheres to itself.

Which product should I use for rigid and flexible PVC window and nailing flanges?

Vycor Pro Flashing contains no asphalt, and is fully compatible with rigid and flexible PVC window nailing flanges.