Precast slabs are available in hollow,
cored, and solid varieties for use on floors, walls, and roofs. For
short spans, various types of panel and channel slabs with
reinforcing bars are available in both concrete and gypsum. Longer
spans and heavy loads most commonly involve cored units with
prestressed wire.
The solid panel and channel slabs are
available in heavyweight and lightweight aggregates. The thicknesses
and widths available vary considerably, but the maximum span is
generally limited to about 10 feet.
Some slabs are available
tongue-and-grooved and some with metal-edged tongue and- groove.
These types of slabs use reinforcing bars or reinforcing mesh for
added tension strengths.
These lightweight, easy-to-handle nail,
drill, and saw pieces are easily installed on the job over the
supporting members. A clip or other special fastener should be used
in placing the slabs.
Cored units with prestressed wire are
used on roof spans up to about 44 feet. Thicknesses available range
from 4 to 16 inches with various widths available, 40 and 48 inches
being the most common.
Each manufacturer must be contacted to
determine the structural limitations of each product. The units
generally have high fire resistance ratings and are available with an
acoustical finish. Some types are available with exposed aggregate
finishes for walls.
Specifications.
The type of material used and the
manufacturer specified are the first items to be checked. The
materials used to manufacture the plank, type and size of
reinforcing, and required fire rating and finish must be checked. The
estimator should also note who cuts the required holes in the planks
and who caulks the joints, and the type of caulking.
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