Concrete Repair Tips
Tip Top Floor
Tips for Buying Your New
Like many other home
dťcor purchases, you may have a particular floor in mind but find yourself
trading off one feature to get another that better suits your needs. It
could be a matter of budget or functionality. We are offering the following
points to consider before you begin the shopping process:
Analyze the conditions around your home
Do you live in an area where there is a lot of sand? Sand can exaggerate
wear on your floor and certain types of flooring perform better where sand
is present. Do you have an asphalt driveway? Asphalt can be tracked off on
certain floor coverings. Do you live in a very high humidity area? Humidity
can effect certain floor coverings.
Analyze the conditions in your home
Do you have pets? Certain types of flooring will resist scratching from
pet's claws or resist staining from those little pet accidents better than
others. Do you have a large family with young children and lots of traffic
on your flooring?
Consider your performance priorities
Do you want ease of maintenance above all else? Maybe you want a longer
lasting floor or greater resistance to scratching. Sometimes it's easier to
evaluate the flooring that you are replacing and decide how the new flooring
should be different.
Match your styling preferences with your performance needs
We think you will find your options exciting. Today's flooring choices often
offer a variety of performance characteristics for any look you might want.
For example, you may want a rustic stone look. You can get that look in
ceramic tile, vinyl, or laminate flooring. Hardwood visuals are available in
real hardwood, laminate, or vinyl flooring.
a high-grade floor covering with one distinct disadvantage it is permeable
like a sponge and liquids and dust particles readily enter the marble unless
protective measures are taken. Immediately after installation the marble
floor should be professionally cleaned, sealed and polished. Then at regular
intervals it should be re-sealed and polished again. Without this
preventative maintenance routine not only will the shine suffer but the
natural colorings will become distorted and fade. Complete restoration is
always possible but expensive. Save yourself that expense by looking after
your marble the way you would any other cherish household effects.
Why Do Concrete Repairs Fail?
In the last few years, many materials and methods have been
developed to repair concrete. Sales representatives selling epoxy resins,
caulks, sealants, and adhesives all promise wondrous results with their
But some experts estimate that up to half of all concrete
repairs fail because many of the concrete repairs materials donít work or
last long, and concrete
repairs are tricky. There are few engineers who have adequate knowledge of
concrete repair, and contractors with experience in concrete repair are
Bryant Mather, formerly the director of the Structures Laboratory, U.S. Army
Corps of Engineers, Engineer Research and
Vicksburg, Miss., and James Warner, a consulting engineer in
were interviewed about concrete repair and failure.
Q: Are most concrete failures due to the incorrect
specifications or the contractor not following the specs?
MATHER: In my opinion itís about 50/50. For example, if the
attack on the concrete by sulfates derived from the soils involved was the
cause of deterioration, it will be clear that the concrete was deficient in
If cement with an appropriate degree of sulfate resistance
was not specified, then the deficiency was in the specifications. If the
proper cement was specified, but was not used, the deficiency was in the
execution of the work in accordance with the specification requirements.
Q: What factors can cause premature deterioration in
MATHER: The main factors are:
ē freezing and thawing
ē aggressive chemical exposure
ē mechanical abrasion
ē corrosion of steel and other embedded metals
ē chemical reactions of aggregates
ē non-uniform volume change
Other factors are: unsound cement with excessive amounts of anhydrate CaO or
plastic shrinkage, the lack of maintained moisture content during the time
when the concrete remains plastic
Q: What causes most serious failures?
MATHER: About a fourth of them will be structural failures
and the other three-fourths will be durability problems.
WARNER: The problems are usually that the concrete is not
appropriate for the intended use and/or is not of sufficient durability.
When water and salt get into concrete, the reinforcing steel corrodes.
Thatís why the concrete cover over the reinforcing steel has to be dense and
of low permeability.
There is a commonly held misconception that high-strength
concrete will provide high durability. This is not correct. Concrete
strength and durability are not directly related. Very high strength
concrete can be of low durability. The measure most often used for concrete
is strength, not durability. But durability is all important.
Q: How do repairs differ from new construction?
WARNER: With new construction, you know where to start. You
can hire your contractor and inspector and make sure everything is right
each step of the way.
With repairs, you never know where you are starting. You donít know whatís
in that structure. Itís very rare that you have the original specs and that
those specs are accurate.
Even with a good condition survey prior to design, many
surprises occur when the contractor opens up the work, and removals are
made. A team approach with close cooperation between designers and
contractors is essential with repair work. Also, the contract documents must
be sufficiently flexible. Changes will occur in most significant repair
Q: If concrete is failing, what should be done?
MATHER: If the concrete is already failing, then you have
to make a thorough inspection of the situation to find out the nature,
extent and cause, of the defect. After you make the inspection, you can
drill cores or break or saw off pieces to examine and check in the
Next, you must decide what to do to the structure. The
first question you must ask is: "Can it be repaired or does the structure
have to be replaced?" Usually the structure can be repaired.
Most problems with concrete can be solved by figuring out a way to keep the
water from getting in. Almost every concrete failure can be traced to a
Q: Why do many repairs fail?
WARNER: Repairs usually fail because of inappropriate
selection of repair material. Many new products have come on the market in
the last several decades. But these materials and their properties, such as
co-efficient of thermal expansion and modulus of elasticity, are often very
different from those of concrete.
When a repair is made in concrete, you have to match the
properties of the repair material to those of the concrete.
Also, some concrete repairs fail because of insufficient or inappropriate
surface preparation such as not removing all the bad concrete or all the
corrosion product from the reinforcing steel.
MATHER: The same amount of negligence when repairing will
do much more damage to the repair that it would to new construction. For
example, if a whole sidewalk dries too soon, it may turn out all right. But
a one-inch patch will curl up and pull away.
Q: Are concrete repairs expensive?
WARNER: In some cases, repairs can cost more than new
construction. Usually, itís not the repair itself that is so expensive, but
what you have to do to get to the point where you can do the repair.
Providing access, scaffolding, selective removal of the faulty concrete,
handling of the debris, and abrasive blasting of the reinforcing all take
time and cost money. Loss of use of a building is also a big factor. Often,
work can be staged so that the building can continue to be used, but this
takes longer and costs more.
MATHER: The thing about concrete repairs is that most
people donít realize the extent of the damage. Then theyíre shocked when
they find out how much it will cost to repair. Let's talk about a building
of steel-reinforced concrete.
When the owner thinks that just the outer one-inch must be
replaced, itís one thing. But inspection reveals that eight inches of the
concrete must be replaced, and the steel must be sandblasted. Letís say the
whole wall is only 16 inches thick. If the owner doesnít understand all of
this, then the cost will shock him.
Q: What recommendations do you have for those who must
write specifications to concrete?
MATHER: First of all, I donít think the architect or
engineer should write the specifications for concrete and concrete repairs.
They should use the specifications provided by the American Concrete
Institute, which are also contained in most of the city and state building
WARNER: Itís difficult to write specs for concrete repairs.
Itís hard to know the actual extent of the repair until the work is actually
done. If youíre going to be specifying concrete and concrete repairs, you
must be keenly aware of the material properties. The annual short course on
Repair of Concrete at the
devotes several hours to this subject.
Also, the International Concrete Repair Instituteís
Guideline No. 03733ó"Guide for Selecting and Specifying Materials for Repair
of Concrete Surfaces" provides a systematic approach to material selection
and includes checklist forms for evaluation of the material requirements.
Itís my considered opinion, that every concrete repair designer and
specifier should use this guideline.
Q: Why is concrete repair such a big issue now?
WARNER: Some of our
design and construction practices in the last 30 or 40 years have not been
as good as they might have been because far too little attention has been given to
the amount of reinforcing cover concrete and the quality of that concrete.
Reliance on the myth that high-strength concrete would automatically provide
good durability has also contributed to concrete failure.