Full Product Manual
wind-driven rain from entering the structure. For wind-driven
rain protection, full coverage with the membrane is recom-
mended. Since Grace Select
™
membrane is a vapor barrier, the
roof construction must allow for proper ventilation in full roof
coverage applications.
Ice Dams
For ice dam protection, Grace Select
™
underlayment should be
adhered at the edge of the roof deck along the eaves. The product
should be applied to a point on the roof deck above the highest
expected ice dam. Several variables inuence the height of ice
dams and the membrane coverage required. Local building codes
should be consulted for specic requirements. Many variables
inuence the height of ice dams including climate (particu-
larly the annual snowfall), slope, overhang, valleys, how well
the structure is insulated and ventilated, and exposure (sun vs.
shade). In addition to placement along the eaves, the product can
be used to help prevent roof leaks in a handful of danger zones
including valleys, rake edges, around chimneys, and skylights.
Installation Procedure
Surface Preparation
Install Grace Select
™
underlayment directly on a clean, dry,
continuous structural deck. Some suitable deck materials include
plywood, wood composition, wood plank, metal, concrete, or
gypsum sheathing. Remove dust, dirt, loose nails, and old roong
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
before installing the membrane.
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 adhe-
sion 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 ft
2
/gal (6–8 m
2
/L).
Priming is not required for other suitable surfaces provided that
they are clean and dry.
Membrane Installation
Apply Grace Select
™
membrane 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 pres-
sure. 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 appli-
cation, 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 nished with the roll go
back to the beginning, reroll and pull the remaining release paper
from the material, nishing the installation.
Consistent with good roong 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, electroplated galvanized nails for fasten-
ing shingles. Hand nailing generally provides a better seal than
power-activated nailing. If nailing of
Grace Select
™
roong underlayment features the inno-
vative Grace Ripcord
®
split release on demand that is
embedded between the underlayment material and the
release liner. When pulled, the cord splits the release
liner into two separate pieces permitting easy position-
ing and installation.
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