b.
Unacceptable Ratios: Where joints of acceptable width-to-depth
ratios have not been provided, clean out joints to acceptable
depths and grind or cut to acceptable widths without damage to the
adjoining work. Grinding shall not be required on metal surfaces.
3.3.2
Masking Tape
Masking tape [shall] [may] be placed on the finish surface on one or both
sides of a joint cavity to protect adjacent finish surfaces from primer or
sealant smears. Masking tape shall be removed within 10 minutes after
joint has been filled and tooled.
3.3.3
Backstops
Install backstops dry and free of tears or holes. Tightly pack the back or
bottom of joint cavities with backstop material to provide a joint of the
depth specified. Install backstops in the following locations:
a.
Where indicated.
b.
Where backstop is not indicated but joint cavities exceed the
acceptable maximum depths specified in paragraph entitled, "Joint
Width-to-Depth Ratios."
3.3.4
Primer
Immediately prior to application of the sealant, clean out loose particles
from joints. Where recommended by sealant manufacturer, apply primer to
joints in concrete masonry units, wood, and other porous surfaces in
accordance with sealant manufacturer's instructions. Do not apply primer
to exposed finish surfaces.
3.3.5
Bond Breaker
Provide bond breakers to the back or bottom of joint cavities, as
recommended by the sealant manufacturer for each type of joint and sealant
used, to prevent sealant from adhering to these surfaces. Carefully apply
the bond breaker to avoid contamination of adjoining surfaces or breaking
bond with surfaces other than those covered by the bond breaker.
3.3.6
Sealants
Provide a sealant compatible with the material(s) to which it is applied.
Do not use a sealant that has exceeded shelf life or has jelled and can not
be discharged in a continuous flow from the gun. Apply the sealant in
accordance with the manufacturer's instructions with a gun having a nozzle
that fits the joint width. Force sealant into joints to fill the joints
solidly without air pockets. Tool sealant after application to ensure
adhesion. Sealant shall be uniformly smooth and free of wrinkles. Upon
completion of sealant application, roughen partially filled or unfilled
joints, apply sealant, and tool smooth as specified. Sealer shall be
applied over the sealant when and as specified by the sealant manufacturer.
3.4
PROTECTION AND CLEANING
3.4.1
Protection
Protect areas adjacent to joints from sealant smears. Masking tape may be
used for this purpose if removed 5 to 10 minutes after the joint is filled.
SECTION 07920
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