Concrete
cracks
By
Frank G. Ross
Concrete, in various applications, is seen in just about every home
I inspect. One thing I find now and then when doing a home
inspection is cracks in the concrete. Concrete cracks in the
driveway, sidewalks, garage floor, and unfinished basement floor are
most common. Occasionally, a buyer will ask me whether the cracks
are a concern. My first response usually is, “There are three
characteristics of concrete: it is usually gray, it gets hard and it
cracks.”
It is practically impossible to determine when a crack
occurred in concrete and if it will get larger and cause damage. A
visual inspection is usually not sufficient to determine why
they happened either. As an inspector I can only look for indicators
that might point to the timing of the crack’s appearance. For
example, if the garage floor has been painted and there are cracks
in the floor but no paint inside the crack then I can deduce that
the crack happened after the floor was painted but when exactly was
that? Possibly the owners can tell when the floor was painted but I
can’t.
Generally what I tell clients is that if the concrete crack does not
have a raised lip on one side and the jagged points of the crack all
line up and the crack is not wider than 1/16 of an inch then most
likely the crack is not a concern. If the crack has a raised lip,
enough to cause a person to trip over it, and/or the irregularities
are not aligned then the crack may possibly have been caused by
settling or movement and a professional contractor should be asked
to evaluate and advise on the crack.
Sealing a crack with a proper concrete sealant is advised for just
about any crack to keep out water that could cause damage to the
concrete due to freeze/thaw cycles or to water undermining the
concrete. To determine the proper way to seal a concrete crack ask a
local concrete contractor to tell you what best works for the size
and placement of the crack you are talking about.
The worst crack I have ever seen was in a vacant home, the wall to
wall carpet had been removed and the concrete slab was cracked from
one end of the home all of the way to the other. The crack was
about ¼ inch wide with a raised lip of about 1/8 inch and the depth
was deeper than 4 inches. The buyers took my advice and hired a
professional concrete contractor to evaluate it. The crack was able
to be repaired, the lip was ground flush and the slab was pronounced
repaired and in good shape.
Frank Ross is a Certified Utah Home Inspector for Pillar to Post
Professional Home Inspection and a full member of the National
Association of Certified Home Inspectors. Readers may contact Mr.
Ross at (435) 867-6400 or
frank.ross@pillartopost.com. You can learn more about Pillar To
Post Professional Home Inspection at
www.pillarposthomeinspection.com
