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DocuSign Envelope ID: B94F2D40-3B3C-47A7-86C2-6F1 B4F92C62C <br /> SECTION 04 01 20-MASONRY RESTORATION <br /> PART 3-EXECUTION <br /> 3.1 EXAMINATION <br /> A. Examine conditions, with Installer present, for compliance with requirements for installation tolerances and other <br /> conditions affecting performance. <br /> 3.2 SAMPLE PANEL <br /> A. Perform tuckpointing and cleaning of CMU masonry on a minimum 3'-0" by 3'-0" wall surface at ground floor as a <br /> sample panel for Owner's and Engineer's acceptance. Execute work on mock-up area as specified and secure <br /> Owner's and Engineer's acceptance prior to proceeding. <br /> B. Prior to cleaning masonry, clean an area selected by Engineer using products and methods specified. <br /> 3.3 MASONRY INSTALLATION, GENERAL <br /> A. Cut masonry units with motor-driven saws to provide clean,sharp, unchipped edges. Cut units as required to provide <br /> a continuous pattern and to fit adjoining construction. Where possible, use full-size units without cutting. Allow units <br /> cut with water-cooled saws to dry before placing,unless wetting of units is specified. Install cut units with cut surfaces <br /> and,where possible, cut edges concealed. <br /> B. Select and arrange units for exposed unit masonry to produce a uniform blend of colors and textures. Mix units from <br /> several pallets or cubes as they are placed. <br /> C. Matching Existing Masonry: Match coursing, bonding, color, and texture of existing masonry. <br /> D. Wetting of CMU: Wet CMU before laying if the initial rate of absorption exceeds 30 g/30 sq. in. per minute when <br /> tested per ASTM C 67.Allow units to absorb water so they are damp but not wet at the time of laying. <br /> 3.4 CONSTRUCTION TOLERANCES <br /> A. Comply with tolerances in ACI 530.1/ASCE 6/TMS 602 and the following. <br /> B. For conspicuous vertical lines, such as external corners and reveals, do not vary from plumb by more than 1/4 inch <br /> in 20 feet, nor 1/2 inch maximum. <br /> C. For vertical alignment of exposed head joints, do not vary from plumb by more than 1/4 inch in 10 feet, nor 1/2 inch <br /> maximum. <br /> D. For conspicuous horizontal lines,such as exposed lintels, sills, parapets,and reveals,do not vary from level by more <br /> than 1/4 inch in 20 feet, nor 1/2 inch maximum. <br /> E. For exposed bed joints, do not vary from thickness indicated by more than plus or minus 1/8 inch, with a maximum <br /> thickness limited to 1/2 inch. Do not vary from bed-joint thickness of adjacent courses by more than 1/8 inch. <br /> F. For exposed head joints, do not vary from thickness indicated by more than plus or minus 1/8 inch. Do not vary from <br /> adjacent bed-joint and head-joint thicknesses by more than 1/8 inch. <br /> 3.5 TUCKPOINTING <br /> A. Rake mortar joints to a uniform depth of 1-1/2 times the width of joint, or 1/2"minimum,whichever is greater. <br /> B. If horizontal bed joints contain block shelf angles or lintels, grind steel and mortar both to a depth of 1/2". Square <br /> shoulder all cuts. Ensure all mortar is removed from masonry unit surfaces within the joints. Wire brush all exposed <br /> steel and apply two coats of a zinc chromate primer prior to tuck pointing. <br /> C. Exercise care when removing mortar to prevent damage to block faces or edges.All masonry units damaged during <br /> mortar removal shall be removed and replaced with matching units, at the Contractor's expense. <br /> D. Remove mortar from joints using mechanical and hand tools. Mechanical tools will be permitted for removing mortar <br /> at bed joints (horizontal joints)and hand tools at head joints (vertical joints). Contractor shall demonstrate ability by <br /> operators to use tools without damage to masonry. <br /> E. Notify Engineer of unforeseen detrimental conditions including voids in mortar joints, cracks, loose masonry units, <br /> rotted wood, rusted metal, and other deteriorated items. <br /> F. Clean joints of all dirt and debris and rinse clean. Leave damp immediately prior to installing pointing mortar. <br /> G. Apply pointing mortar first to areas where existing mortar was removed to depths greater than surrounding areas. <br /> Apply in layers not greater than 3/8 inch until a uniform depth is formed. Fully compact each layer thoroughly and <br /> allow it to become thumbprint hard before applying next layer. Fill joint with mortar type specified. <br /> H. Install mortar full depth of cut, ensuring a densified placement of mortar. Do not leave voids or gaps in installation. <br /> I. Tool exterior joints when "thumb print" hard. Joints shall be tooled to match existing, using a jointer at least 1'-0" in <br /> length. Pointing mortar for exterior joints shall be in color matching existing mortar. <br /> J. When mortar reaches green state, cut and lightly brush mortar with a soft bristle brush to seal edges and remove <br /> excess mortar and droppings. <br /> K. Mask off lower wall areas to prevent mortar droppings from rebounding or splattering walls. Cover all roof areas and <br /> sidewalks to prevent staining. Remove stains and repair or replace damage from staining. <br /> ©BOOMERANG DESIGN 0401 20-4 510 Meadowlands Drive,Hillsborough,NC <br /> BD#1835 ORANGE COUNTY, NC 12/07/2018 <br />