Questions and Answers about Foundation Repair in
Dallas/Fort Worth
1.
Why does the Dallas/Fort Worth area have so many homes
that have foundation problems?
2.
Is it true that trees can cause a foundation to settle?
3.
What is meant by “seasonal” foundation movement?
4.
When is foundation movement considered to be severe
enough to warrant repairs to the foundation?
5.
How does installing piers help my foundation?
6.
I am not familiar with construction techniques. How do I
know the foundation repair contractor is repairing my foundation
in accordance with the engineer’s specifications?
7.
Can poor drainage conditions around a foundation cause my
foundation to move?
8.
Will adding rain gutters help control foundation
movement?
9.
Will installing a sprinkler system help control
foundation movement?
10.
What does it mean to be a professional engineer?
Why does the Dallas/Fort Worth area have so many homes that have
foundation problems?
Most of the foundation movement in the metroplex area is the
result of the foundation responding to
variations in moisture
content of the soil. The soils in most of the North
Texas and certainly the DFW area
have a high clay content. As such, when the expansive clays
absorb moisture, they tend to swell.
Likewise, when they dry,
they tend to shrink. This repeated shrink/swell action many
times causes a foundation to move up and down.
However, there are several other reasons foundations move
that are not related to soil moisture content. For
example, when a slab foundation
is constructed over loose fill material. (fill material is dirt
the builder/developer uses to level the lot prior to the
installation of the foundation.) If the fill material dirt was
not properly compacted during construction, it will eventually
consolidate (settle). When this occurs, a foundation built on
top of the fill can settle, also.
Is it true that trees can cause a foundation to settle?
Yes, there has been considerable scientific research done on
this subject. Generally speaking, tree roots absorb large
quantities of moisture from the soil. Consequently, trees can
affect the soil’s moisture content under and around foundations.
A large shade tree can transpire as much as 200
gallons of water
per day. Trees “transpire” or release water into the air in the
form of vapor. The water for transpiration comes from the soil
by the way of the roots. This is why trees are known to “pull”
water from under a foundation, but only when water in the
surrounding soil is inadequate or unavailable.
Basically, if
roots are near and/or under a foundation, then the soil in the
area of the roots is usually drier than in those areas away from
the roots. As the soils dry out, they shrink. This shrinkage
sets up the potential for a foundation to settle. However, since
water naturally moves through the soil from high-moisture areas
to low moisture areas, simply not watering at all can cause
foundation problems regardless of nearby trees. Trees can
certainly add to the problem, but are usually not the primary
cause of moisture loss from the soil.
Having said
all that, the usual remedy to a situation where it has been
determined that a tree has had a negative impact on a foundation
is to either remove the tree or install a root barrier between
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| root barrier |
the tree and the foundation. A root barrier is a ditch that is
typically 12" or so wide (the one shown in the photo is 6" wide)
approximately 3 to 4 feet deep and has an impenetrable barrier
place in it to keep the roots from gaining access to the soil
immediately around the foundation. Since the installation of the
barrier may cause damage to the tree, it is recommended that the
client consult with an Arborist to determine if the tree should
be trimmed back before/after the installation of the root
barrier.
It should be noted that if a slab foundation is
constructed near or over the roots of a mature tree and if the
tree is cut down, some unwanted upheaval of the foundation may
occur as the soils rehydrate. This situation should be evaluated
by an arborist or an experienced engineer.
What is meant by “seasonal” foundation movement?
Seasonal foundation movement occurs as the soils absorb water
during times of rain (typically during the winter and spring
months)
and lose water during times of no rain (typically the
dry summer months). Clay-rich soils typically expand as they
gain water and shrink as they lose water. This
expansion/contraction can cause a foundation to move up and
down.
If foundation movement is due only to seasonal weather
changes, this can be considered a somewhat “normal” occurrence
and typically causes only relatively minor cosmetic damage to the
sheetrock and/or brick veneer.
In most of these cases, depending
upon the soil conditions, a sheetrock crack can grow wider
during the dry summer months but then close back up during the
wet winter/spring months (or visa versa). It is common for slab
foundations to experience some “seasonal” foundation movement in
the DFW /North Texas area.
When is foundation movement considered to be severe enough to
warrant repairs to the foundation?
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| out of level door |
Foundation
repairs are usually needed
when the livability of a residence is
impacted. Examples of this include excessive floor slopes, large
cracks in the sheetrock walls, doors become difficult to
operate, etc. Also, all of these factors can reduce the
value of a property.
How does installing piers help my foundation?
The installation of piers under a foundation increases the
rigidity of the foundation and helps it to withstand the
movements of the soil. Properly designed & installed piers are
very
effective in stopping further settlement of the foundation,
in the area of the piers. It is important that the piers be
designed by an experienced engineer who understands
the soil conditions of the area.
There are basically two reasons
to install piers:
• To stop any further downward movement
(settlement) of the foundation – in the area of the piers.
(Under normal circumstances, a pier will only influence an area
within a 7 or so foot radius.)
• To help bring portions of the
foundation to a more “level” position – in the area where the
piers were installed.
I am not familiar with construction techniques. How do I know
the foundation repair contractor is repairing my foundation in
accordance with the engineer’s specifications?
It is highly advisable to have the work of a repair contractor
inspected by an independent engineer to insure compliance with
the design drawings and specifications. This includes inspecting
the work during the installation of the repair plan, and
after the repair is completed. At that point, the engineer should write
a letter to the homeowner that confirms that the repair
contractor complied with the design specifications.
In fact, if
the residence is either being purchased or re-financed, many
lending institutions require that an engineer provide such a
compliance letter. At GeoDynamics, we are always willing to
ensure that the foundation repairs are being done in compliance
with our engineering design requirements. There is an additional
charge for this service.
Can poor drainage conditions around a foundation cause my
foundation to move?
Absolutely. Poor drainage conditions allow an
excessive amount of water to soak into the soils. This can
trigger an expansion of the clays (how much expansion is a function
of several factors
 |
| poor drainage |
including the soil characteristics and
dryness of the clays prior to the absorption of the water). If
the clay expands enough, it can cause a foundation to heave
upward, sometimes significantly.
Some areas of the DFW metroplex have soil that is very
susceptible to moisture expansion (and foundation movement
up to 12” has been recorded), while foundations in other
areas of the metroplex that have
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| proper drainage |
poor to marginal drainage patterns and are not significantly
impacted.
It is a generally
accepted fact in the DFW area, that to minimize the potential
for foundation movement, the homeowner should attempt to keep
the moisture content of the soil at a constant rate, year around
(i.e., do not allow the soil to get too wet and do not let it
get too dry). This usually means that it is important to have
drainage conditions around a foundation that will allow the
surface water to drain rapidly away from the foundation and
then, in time of drought (summer months), not allow the soil to
become too dry (this requires watering the soil).
Will adding rain gutters help control foundation movement?
|
| rain gutter downspout
installed into a buried drain pipe |
The
installation of rain gutters around the roof line will greatly
aid in controlling excess water as long as the downspouts are
positioned so that they deposit the water several feet away from
the foundation. The preferred method of doing this is to install
the downspouts so they terminate into a buried drain pipe and then
discharge the water far away from the house.
It is estimated that over 700 gallons of water come off a
roof of a 1200 sq. ft. house after a 1" rain.

Will installing a sprinkler system help control foundation
movement?
A sprinkler system can make it more convenient to keep the soil
around a foundation at a constant moisture content. If you are
considering installing a water sprinkler system, it is suggested
that the water valves be at least 5 feet away from the
foundation. Additionally, if feasible, it is a good idea to have a zone
designated strictly for the soil around the foundation. This
way, during the summer months (or when there has been no rain),
it is possible to water the soil around a foundation more evenly
and without having to over-water the rest of the yard to keep the soil
around the foundation moist.
What does it mean to be a professional engineer?
Professional Engineers in Texas are certified by the Texas Board
of Professional Engineers as being qualified to practice
engineering in Texas. Once certified by the Board, the engineers
may use the designation "Engineer", "Professional Engineer", or
"P.E."
after their names. Typically in Texas, in order to become a
certified Professional Engineer, the candidate must complete the
following:
Receive a degree from an accredited college
that has an approved engineering curriculum. The curriculum for
an engineer must include 8 semester hours of mathematics beyond
trigonometry, including differential and integral calculus and
20 semester hours of related engineering sciences. For a
structural engineer, this typically includes subjects such as
mechanics of materials, thermodynamics, fluid mechanics,
structural analysis, etc.
After graduation from an accredited university, have 4 years
of active, verifiable experience of engineering work.
At least 3 references
from licensed professional engineers. These engineers must have
a personal knowledge of the applicant’s character, reputation,
general suitability for a license, and engineering experience.
Engineering Firms Engineering firms in Texas can obtain legal
engineering status only through the licenses of their own
licensed professional engineers who are full-time employees.
They cannot obtain a license to practice engineering by using
part time employees who are engineers. The registration of the
engineering firm gives a company the legal authority to offer
the engineers’ services to the public.