essay 2-3 pages Cost & Estimating
Ssult89
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CSMT 441
Masonry Units
Lecture 9
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Division 4 - Masonry
• Concrete Masonry Unit (CMU)
• Brick
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Concrete Masonry Unit
• Separate masonry according to:
– size of the units
– shape of the units
– colors of the units
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Concrete Masonry Unit
• The standard modular face dimensions of the CM
units are 7 5/8" high and 15 5/8" long.
Thicknesses available are 3, 4, 6, 8, 10, and 12
inches (nominal, actual dimensions are 3/8"less).
• A 3/8" mortar joint provides 8"x16" face
dimension (112.5 units per 100 sf of wall).
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Concrete Masonry Unit
• Thicker face shells are required for a specific fire rating.
• Unit: No of units required (SF of wall x 1.125)
• Deduct all openings in excess of 10 sf.
• Allowance for waste and breakage:
– 5 -10%
• Cutting of the units is expensive and should be anticipated.
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Bricks
• Brick is a solid masonry made of clay.
• Bricks are classified by:
– kind (common or face)
– size
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Bricks
• No. of brick per square foot of wall depends on:
– size of brick (standard size: 2 1/4"x 3 3/4"x 8")
– width of the mortar joint
• For running bond with 3/8" thick mortar joint,
number of standard brick per 100 sf is 675
• Make deduction for all openings
• Waste
– 5 to 10%
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BCN5618 11
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Mortar
• Masonry mortar usually consists of Portland
cement, mortar sand, and hydrated lime.
– Type M - 1:1/4:3 mix by volume - 1 part cement, ¼ part lime 3 parts sand) for heavy loads and below grade
– Type N - 1:1:6 for use above grade
• 3/8" is a common mortar joint thickness, but 1/4"
and 1/2" joints are also used.
• Colored mortars (red, brown, white, and black)
may be used.
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13 Volume of mortar for block (cf) = (Net area x 3.2)/100
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Coping
• Covers the top course
of a wall to protect it
from the weather.
• coping block (no of
units)
• stone (lf, note type,
width, and thickness)
• precast concrete (lf,
note width, thickness,
and finish)
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Sills
• members at the
bottom of window
or door openings
• brick (no. of units)
• stone (lf, note type,
thickness, and
width)
• precast concrete (lf,
size)