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SLAB CRACKS SLAB DETERIORATION
9150
SLAB CRACKS / DETERIORATION
NOTED:
As concrete cures it slightly shrinks. This
shrinkage often results in "hairline"
cracks. If the crack is no larger than 1/4 inch
wide, it may be ignored under most conditions.
The crack may be more serious if either side of
the crack shows signs of lifting or settling.
Generally you may ignore minor cracks caused by
shrinkage or by poor finish work. Larger cracks,
or cracks which indicate possible ongoing
settlement, should be reviewed further in an
attempt to locate the cause. If the slab crack
is affecting ceramic tile which is installed
over the crack it may be necessary to remove the
tile and install new tile over a special
adhesive designed for cracked concrete.
Generally slabs will be reinforced with wire
mesh or reinforcing bars which help maintain the
integrity of the slab whether cracked or not.
Some slabs have steel cables running through
them and are known as "post-tension
slabs." The tension is applied after the
concrete has cured to a certain degree. The
tensioning devices pull the slab together under
great pressure causing it to perform as one
rigid piece. Post-tension slabs are considered
"structural" in that they carry the
building loads directly, as they
"float" on the earth. Although it has
small footings the slab performs a more critical
function than do slabs of other systems. Because
of this cracks in post-tension slabs can be more
serious than in other slabs. Because flooring
materials cover the slab and are not lifted, the
inspection is obviously limited to the visible
portions of the slab and footings. In most cases
cracks in slabs are ignored, but use your own
judgement. This is one item which could call for
an additional opinion, especially since the
inspector is performing a visual inspection and
often cannot effectively ascertain the exact
nature of a crack or other adverse condition.
More severe cracking, where the slab has shifted
or where differential movement is noted may be
due to earth settlement or movement. You are
advised to consult with a Geotechnical Engineer
if settlement-caused slab cracks are noted. If
there are no serious warning signs, fill the
crack with an epoxy modified cement, plaster
patch, or mortar (available at most Building
Supply Outlets). More serious conditions may
require removal and replacement of the affected
section. Concrete slabs will exhibit spalling
conditions in some high alkaline areas and in
areas where freeze exfoliation occurs. This
appears as spots of concrete flaking off and/or
a "whitish" deposit in and around the
affected area. Spalling conditions are usually
repaired on a temporary basis. The cause of the
spalling, being in the ground, renders one
unable to effect long-term permanent repairs.
Moisture must be kept from penetrating the
affected areas. If further information or
assistance is needed for repairs, you may wish
to contact a qualified Concrete Contractor.
The above information was provided by TWI Systems Copyright 1995-2005 1-800-553-5660
TILT-UP CONCRETE CONSTRUCTION
BLOCK / BRICK CONSTRUCTION
POURED CONCRETE WALLS
FRAME CONSTRUCTION
Post-tensioned slab preparation. .
TREATED SILL / SOLE PLATE
OTHER SILL / SOLE PLATES
WOOD FRAMING
1984 TO PRESENT
1963 TO 1983
1950 TO 1962
1930 TO 1949
1900 TO 1929
PRE-1900
ATTIC VENTILATION
FOUNDATION VENTS
ATTIC FAN
TERRA-COTTA FOUNDATION AND/OR, IF VISIBLE, FOOTING
BLOCK FOUNDATION (FOAM / CONCRETE)
CONCRETE FOUNDATION AND/OR, IF VISIBLE, CONCRETE FOOTING
BRICK / STONE FOUNDATIONS AND/OR, IF VISIBLE, FOOTING
RAISED / BELOW-GRADE FOUNDATION SYSTEM
CAISSONS or PILES
POLE / COLUMN
NONCONTINUOUS FOUNDATION AND/OR, IF VISIBLE, FOOTING / JACK
STANDS
POST AND PIER OR POST AND BEAM
BOLTED SILL PLATE
GRADE BEAMS
BASEMENT
SINGLE-FAMILY RESIDENCE
CONDO / HOA / TOWNHOUSE
DUPLEX / MULTIUNIT / COMMERCIAL
MOBILE HOME / MANUFACTURED HOME
SUBTERRANEAN PARKING
BATT OR BLANKET TYPE INSULATION
LOOSE FILL INSULATION
RIGID SHEET INSULATION
AIR / VAPOR / MOISTURE BARRIER
APPROXIMATE INSULATION THICKNESS
ATTIC FULLY TRAVERSED
ATTIC PARTIALLY TRAVERSED
ATTIC OBSERVED FROM ACCESS OPENING ONLY
SUB AREA FULLY TRAVERSED
SUB AREA PARTIALLY TRAVERSED
SUB AREA OBSERVED FROM ACCESS OPENING ONLY
SUB AREA NOT REVIEWED
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