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For a thorough foundation inspection, contact a
professional engineer. Foundation engineering and
inspection is a necessity when walls continue to crack
or produce cracks greater than 1/16th of
an inch, at which point water can pass through the wall.
Structural Design Solutions has inspected foundations
and engineered solutions for the Charlotte areas as well
as Gastonia, Shelby, Lincolnton, Concord, Denver, and
other surrounding areas. Please feel free to
contact us for any questions you have about the severity
of your foundation cracks. Remember that it is
always easier to solve foundation problems early, as in
most cases cracking will continue to get worse over
time.
Foundation
Wall Cracking
General Overview
No matter how much attention is given to foundations
during construction, foundations will crack when the
soil beneath moves, upward, downward, and laterally.
Foundation and building walls are typically design to
only accommodate very small amounts of movement.
In terms of residential buildings, the tolerance is
significantly less. Due to the relatively light
load the house must withstand, the foundations and
structural walls are designed accordingly, thus when
movement occurs, the residential structure is more
likely to crack. Most residential walls are not
designed to withstand this additional ground movement.
Crawlspace
Cracks
Foundation cracks that occur in the crawlspace are most
likely due to foundation settlement as opposed to
lateral earth pressure from backfill. Therefore,
cracks usually stair-step down the foundation. By
investigating the crack size and shape, Structural
Design Solutions can determine the exact cause.
Chimney Movement
The NC Building code ensures that contractors pay close
attention to chimney foundations. Due to the
weight of the chimney, large foundations are typically
used beneath. However, depending on the
workmanship of the contractors, the age of the house, or
the occurrence of unanticipated bad soil beneath the
footing, the chimney foundation may settle. When
this settlement occurs, the chimney rotates to create
either a separation between it and the house or pushes
into the house. Both scenarios are equally
problematic. Without proper engineering analysis
and foundation stabilization techniques, the leaning
chimney could be potentially dangerous. We
recommend that when chimneys are leaning, please contact
a structural engineer to determine the severity of the
issue.
Basement Cracks &
Waterproofing
Basement walls are foundation walls that retain
backfilled soil. Therefore, these walls experience
both vertical and horizontal pressure that can cause a
variety of structural and serviceability issues that can
lead to foundation failure.
Basement
walls must first support the structure above, which rest
directly on the walls. The walls then rest on the
ground beneath. When the soil begins to move, the
foundation walls will crack depending on the amount of
movement that has occurred. These cracks usually
appear in a stair-stepped pattern. Various other
type cracks may appear as a result of soil settlement,
however, the stair-stepped is the most common. By
having a structural foundation inspection, the types and
locations of the cracks can be examined to determine the
cause.
The next
type of load the basement walls must resist is lateral
earth pressure, which is induced by the backfill behind
the wall. When walls are over-stressed, the wall
will crack in a horizontal pattern. The
over-stressing or over-loading can result from a number
of issues including under-designed foundation wall,
hydrostatic (water) build-up behind the wall due to
inadequate drainage, or potential surcharges (heavy
loads resting on the ground near the walls).
If proper
drainage is not provided, the walls will typically crack
to relieve the (water) pressures behind the wall.
Once cracked, the water is free to pass through the wall
if a proper waterproofing membrane (not painted on tar
or damp-proofing paint). If basements are leaking,
the structural damage has typically occurred and will
continue to increase in severity if the problem is not
solved. It is always recommended to consult a
professional engineer before a new water-proofing system
is installed. A hydrostatic (water) accumulation
behind the wall can cause serious damage, which will
accompany the new system if not properly installed.
Interior
House Cracks
Most interior wall cracks are direct indicators of
foundation settlements. As the soil settles, the
foundation follows. The relatively weak sheetrock
cracks as the walls move. Stress relieving cracks
usually follow the path of least resistance, thus
typically tend to extend off of door and window corners.
However, many factors affect the crack location and
direction. As cracks are typically signs of wall
movements, the windows and doors will soon shift as
well. This condition produces addition friction at
the doors and windows, thus they tend to stick and jamb.
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