Print this pageDon’t Mess with a Geophysicist’s House: A Case Study of Ground
Penetrating Radar (3D) for Concrete Moisture Mapping and Void
Detection in the Saturated 
Soil
beneath the Concrete Foundation
Mustafa Saribudak
Environmental Geophysics Associates, 2000 Cullen Ave., Ste. 7, Austin, Texas 78757
Texas has large areas, including Houston, with clayey soils that shrink and swell
with changes in soil moisture content. This shrinking and swelling may cause movement
of residential foundations that adversely affects the residence. Different levels of moisture
around the perimeter and under the buildings can create voids, upheavals, slumping,
and other foundation problems.
Clayey soil is present throughout the area where the subject residence is located in
the northwest part of Houston. This type of soil expands when it gets wet, and shrinks as
it dries.
The house is 8 years old and the the homeowner replaced the carpets in the living room with wood flooring about one year after they moved in. The wood floor started showing discoloring within 3 months after they were installed.
An engineering company was contracted to evaluate the moisture problem in the
living room. However, results from the plumbing and engineering studies of the mechanicals
could neither pinpoint the source of the moisture specifically nor the conditions
of the concrete slab and the soil
beneath it. To address the problem, the homeowner
hired his own geophysical company to perform ground penetrating radar surveys in
the living room.
Ground penetrating radar (GPR) results indicate a significant void beneath the concrete foundation, two post-tension cables (PTC) within the concrete and a moderate ‘anomaly,’ that correlates well with the discolored, moisture-affected areas of the wood floor This correlation suggests that moisture wicking through the concrete foundation at the disintegrated PTC could have cause the water damage in the living space.
AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012