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, poured cement walls, foundation walls, retaining 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