Installation Guide

Grace Construction Products
Grace Underlayments
Application procedures for self-adhered
underlayments
Surface Preparation
Install Grace underlayments directly on a
clean, dry, continuous structural deck. Some
suitable deck materials include plywood,
wood composition, wood plank, metal,
concrete, or gypsum sheathing. For all other
substrates, contact your local Grace represen-
tative. 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. Repair
deck areas before installing the membrane.
Priming
Prime concrete, masonry surfaces and Dens-
Glass 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 ft
2
/gal (6–8 m
2
/L). Priming is not
required for other suitable surfaces, such as
plywood and some gypsum sheathing,
provided they are clean and dry.
Membrane Installation
Apply Grace underlayments 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.
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.
*NOTE: For valley and other detailed application
areas (for example: rake edges, around dormers),
Grace Ice & Water Shield
®
and Grace Select
contain Ripcord
®
, a thin monofilament line located
in the center of the roll and slightly embedded in
the rubberized asphalt. This “Split-Release on
Demand” function facilitates a quicker and easier
installation of the underlayments.