3.2.6.3
Alkaline Chemical Cleaning - Prewash Phase
Alkaline chemical cleaners shall be applied according to manufacturer's
instructions. Alkaline cleaners shall be applied to masonry surfaces by
low pressure spray 0.35 Mpa 50 psi max., roller, or brush. Cleaner shall
remain on masonry surface for the time period recommended by the
manufacturer. Manual scrubbing by brushes shall be employed as indicated
by test patches for the specific location. Cleaned surfaces shall be
rinsed with a low-to-moderate pressure spray of water.
3.2.6.4
Alkaline Chemical Cleaning - Afterwash Phase
Immediately after rinsing of alkaline cleaned surfaces, a neutralizing
afterwash shall be applied to the cleaned masonry areas. Neutralizing
afterwash shall be applied according to manufacturer's instructions.
Neutralizing afterwash shall be applied to masonry surfaces by low pressure
spray 0.35 Mpa 50 psi max., roller, or brush. Afterwash shall remain on
masonry surface for the time period recommended by manufacturer. Cleaned
surfaces shall be rinsed with a low-to-moderate pressure spray of water to
remove all traces of chemical cleaners.
3.2.6.5
pH Testing
Masonry surfaces which have been chemically cleaned shall be pH tested
using pH monitoring pencils or papers. Chemically cleaned masonry shall be
rinsed of all chemical residues until a neutral pH (7) reading is obtained
from the masonry surface.
3.3
MASONRY REPAIR
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NOTE: Provide missing information; if a reference
is added, revise paragraph REFERENCES accordingly.
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Repaired surfaces shall match adjacent existing surfaces in all respects.
Masonry repair shall proceed only after the cause of deterioration has been
identified and corrected. Masonry repair shall conform to ACI C-20.
Repair of terra cotta masonry shall [be as directed] [conform to [_____]].
Masonry repair shall proceed only after the area to be repaired has been
cleaned. The materials, methods and equipment proposed for use in the
repair work shall be demonstrated in test panels. The location, number,
size and completed test panels shall be subject to approval. Products
shall be used in accordance with the manufacturer's instructions.
3.3.1
Repointing
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NOTE: Provide missing information; if a reference
is added, revise paragraph REFERENCES accordingly.
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Repointing work shall be [as directed] [in accordance with [_____]]. Old
caulking, grout, or mortar shall be removed from previously repaired cracks
where it is failing. Loose particles shall be removed from cracks. Cracks
shall be cleaned, rinsed with water followed by blowing with filtered, dry,
SECTION 04900
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