TM 5-805-6
Table 1. General Guide to Sealant Selection-Continued
*
Sealant/
Cure
Total Joint
Movement
Design Life/Comments
Primary Use
Substrates
Time
Shrink
25%
CSPE
Porous
Slow
Yes
5 to 20 yrs. Resists water, chem-
Chemical resistant
icals, & petroleum products.
membrane or coating
Chloroprene
Slow
25%
5 to 20 yrs.
Porous
Yes
Swimming pools
See CSPE.
Porous
None
None
2 to 5 yrs.
Non-skinning
No
Do not paint.
Acoustic seals
10%
5 to 20 yrs. Protect from UV &
Butyl
All
Slow
Yes
ozone; good water resistance
Water seal,
Small joint movement
100%
Up to 20 yrs.
Preformed &
All
None
No
All types of joints.
Resilient Sealants
* NOTE: "All" substrates include glass, metal, finished wood, and porous materials. "Porous" materials are concrete, masonry and
unfinished wood.
available as preformed sealants.
d. Exterior moving joints. The elastomeric seal-
ants based on polysulfide, polyurethane, and sili-
11. Radon. For controlling radon in low rise
cone provide excellent resistance to weather. Stan-
buildings, ASTM E 1465 provides design options
d a r d classes are 12.5 and 25 percent joint
for sealing and ventilating slabs, basements, and
movement. Sealants capable of 50 percent joint
crawl spaces. When applied, these "options"
movement are available.
should incorporate the joint designs and sealant
e. Exterior joints, heavy abuse. Of the elastome-
selections established in this manual.
ric sealants, polyurethane usually provides the
best resistance to abrasion or penetration as re-
12. Fire Resistance. Most sealants are combusti-
quired for a sealant exposed to abuse and traffic.
ble. Exceptions to this are teflon and kynar seal-
f. Joints in exterior insulation and finish systems
ants which will break down at temperatures in
(EIFS). Most types of EIFS will deteriorate quickly
excess of 700 degrees F. Polychloroprene, CSPE,
if moisture penetrates into the layers of insulation,
and some silicone sealants are generally "self-
base coat, and top coat. Properly sealed joints
extinguishing." Sealants for fireproofing are spe-
prevent moisture from entering the EFS joints and
cially formulated to pass flame spread and smoke
exposed edges. When the finish coat is coarse, the
requirements. Control and expansion joints in
sealant must be adhered to the base coat which is
fire rated construction will be designed in accord-
turned down into the joint; otherwise, moisture
ance with Series J900, U900, and U400 of the
will migrate through the edges of the finish coat,
UL Fire Resistance Directory; firestopping will be
release the sealant's adhesion, and enter through
in accordance with Military Handbook MIL-
the joint into the EIFS and underlaying struc-
HDBK-1008.
tures. Manufacturers provide or specify sealants
13. Joint Details. Most joints will be configured
and details for sealing each EIFS system.
as shown in figures 4 and 5. One of the adjacent
g. Joints subjected to chemical exposure. Use
materials may extend beyond the face of the joint
CSPE or polychloroprene (Neoprene) sealants when
(e.g., when a window casing is sealed to masonry,
exposures are anticipated to aliphatic solvents,
or when a pipe is sealed in a sleeve and the sleeve
petroleum products, water, and numerous other
is sealed in a wall), but this does not affect the
chemicals. Preformed sealants made from fluoro-
basic joint configuration. In deep joints, a backing
or fluoro-chloro-carbon polymers (such as teflon
material should always be required to hold the
and kynar) will resist many very active chemicals.
sealant in place while it is being inserted and
h. Joints subjected to temperature extremes. Most
tooled. Without backing, tooling can dislodge the
(but not all) silicone sealants retain good flexibility
sealant. If a sealant is not tooled, it may not fill
at temperatures as low as -54 degrees C (-65
the joint, and air bubbles may penetrate the
degrees F); and will not deteriorate when exposed
sealant, form blisters, or mar the surface.
to temperatures as high as +204 C (400 F).
a. Stationary joints. A joint is stationary (or
Polytetrafluoroethylene (Teflon) sealants will re-
fixed) where the adjoining materials are not free to
sist higher temperatures but are generally only
12
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