Full Product Manual

Suitable for use under asphalt shingles and most
other major roof coverings
Grace technical support—Grace SYN 15
™
underlay-
ment is backed by a team of local technical support
personnel that help ensure every application goes
smoothly.
Installation Guidelines
1. The roof deck must be swept clean and be
smooth and dry before installation begins.
2. Grace SYN 15
™
underlayment is laid horizon-
tally (parallel to eave), starting at the bottom of the
roof, with printed side up and with 4-inch side laps
and 6-inch end laps. Side laps run with the ow of
water in a shingling manner.
3. Grace SYN 15
™
underlayment should not be
used at slopes less than 2:12, provided the slope is
also acceptable to the primary roof covering. On
slopes of less than 3:12, Grace SYN 15
™
underlay-
ment should be half-lapped a full 24 inches over the
underlying course, shingle style.
4. Grace SYN 15
™
underlayment is attached to
the roof with roong nails or staples both having
1-inch diameter plastic/metal caps or other fasten-
ers approved by Grace, spaced at 8 inches on center
(oc) on both side and end laps in normal wind zones.
In high wind zones or coastal applications, double
the fastening to 4 inches oc. In all cases fasten at
24 inches oc down the middle of the roll in the eld
of the roof. Capped nails and staples may be hand
or machine applied. Nails or staples without caps
cannot be used.
5. Where seams or joints require sealant or adhe-
sive, use a high quality, low solvent, asbestos free
plastic roong cement meeting ASTM D4586 Type
1, Federal Spec SS-153 Type 1 (Asbestos Free).
Consult your local Grace representative for more
details.
6. Install drip edge at eaves under underlayment
and at rake over underlayment.
7. Installation of the roof covering can proceed
immediately following underlayment application.
Grace SYN 15
™
underlayment cannot be used as a
primary roof covering. The product is not designed
for permanent outdoor exposure. The installation of
the nal roof covering should take place within 30
days.
8. For additional protection lay a single length of
Grace SYN 15
™
underlayment vertically in valleys
and on hips prior to installing metal ashings (if
used) and before installing horizontal underlayment.
Return Grace SYN 15
™
underlayment up all abut-
ments at least 12 inches (more in heavy snow areas).
Secure and trim to suit.
9. Prior to loading roong materials on Grace
SYN 15
™
underlayment it is recommended that roof
jacks, toe-boards or a storage platform be secured
to the underlying roof deck to prevent slippage of
stored materials on steep sloped roofs. See OSHA
Regulations (Standards – 29
Used only capped nails or capped staples.
Lay with a minimum 6 inches end lap.
Use a 4 inch side lap. Follow printed
guidelines for easy installation.
Fasten at 24 inches oc in the
middle of the roll.
56