result from removal, cleaning, and repair operations.
3.3.2.2
Application of Masonry and Mortar
Masonry and mortar shall be placed to rebuild spalled or damaged areas to
match the original surface finish, level, texture, and color. The finished
appearance of the patch shall match the adjacent existing surface.
3.3.2.3
Patch Anchors
Patch anchors shall be provided to ensure that the patch is tied to the
existing masonry structure. Patch anchors shall be provided at a frequency
of at least one patch anchor per 93 square mm square foot of patch plan
surface area; specific locations for patch anchors shall be as indicated.
Small handheld, low-speed rotary masonry drills shall be used to produce
holes in the existing masonry, within the limits for the patch anchor
installation.
3.3.2.4
Holes
Holes shall be drilled into the existing substrate material of the masonry
using rotary (non-hammer) drills. Holes shall have a diameter of 3 mm 1/8
inch larger than the anchor diameter. The holes shall be drilled to a
depth of 100 mm 4 inches, except as otherwise indicated or directed. Drill
holes shall not penetrate completely through the masonry, and shall provide
at least 25 mm 1 inch of cover around the drill hole. Holes shall be
cleaned by water blasting to remove drill dust and other debris and then
blown dry with filtered, dry, compressed air. Drill holes shall be
conditioned in accordance with the epoxy adhesive manufacturer's
recommendations.
3.3.2.5
Anchor Installation
Anchors shall be cleaned to remove all contaminants which may hinder epoxy
bond. Epoxy adhesive shall be pressure injected into the back of the
drilled holes. The epoxy shall fill the holes without spilling excess
epoxy when the anchors are inserted. Anchors shall be inserted immediately
into the holes. The anchors shall be set back from the exterior face at
least 25 mm 1 inch. Anchors shall be installed without breaking or
chipping the exposed masonry surface.
3.3.2.6
Cleanup
Excess epoxy and spills shall be removed from the surface of the masonry.
The surface of the masonry shall be left in a clean and uncontaminated
condition. Spills on adjacent surfaces shall also be removed and surfaces
repaired as required.
3.3.2.7
Dutchman Repairs
The piecing-in of small patches of masonry to repair or replace damaged
areas (Dutchman repair) shall be used in areas indicated. Repair pieces
shall be held in place with epoxy with the joint between the new and old
materials kept as narrow as possible to maintain the appearance of a
continuous surface. Repairs shall be made to blend in with the surrounding
original materials as closely as possible.
SECTION 04900
Page 18
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