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Frequently
Asked Questions About Concrete Leveling
Why does Concrete Sink?
Offsets or “tripping hazards”
are created when concrete slabs sink. In addition to personal
or business safety concerns, a concrete slab may develop improper
“pitch” or the angle of water run-off. Serious foundation
and structural damage can result from improperly “pitched”
concrete.
Concrete
slabs are often installed on poorly compacted fill dirt. Sub-surface
erosion and shrinking soil, such as the clay found in Northeast
Ohio are also contributing factors. Fill dirt is almost always
placed closest to the sides of a new house and garage, after the
foundation work is completed. Time constraints and completion
deadlines make it difficult for a builder to take the time to
properly compact this dirt. Natural settling often takes seven
years or more in areas of clay soil.
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What
is Concrete Leveling?
Many people have replaced slabs
that are in perfect condition only tilted or sunken. Demolition
and replacement of concrete is expensive, messy and time consuming.
The term Concrete Leveling has been used since the inception of
the industry. Industrial terminology can be confusing. The purpose
of the process is to eliminate “offsets” or “tripping
hazards”, or to properly “pitch” (angle) the affected
slabs. If concrete were actually level, water would not run off.
A more accurate term would be, "Concrete Raising."
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How
does Concrete Leveling work?
The
technology to lift concrete has been around for centuries. It
is the same concept that your mechanic uses to raise your car
on a hydraulic lift. Concrete Leveling is a process that involves
pumping a dense material, under pressure, underneath a sunken
concrete block, raising it into its original position.
1.
A small (1 inch) hole is precisely drilled through the affected
concrete block.
2.
A highly dense, finely crushed limestone (sometimes combined
with cement), is mixed with water in a “slurry” consistency
and pumped into the holes. The material fills any “void”
areas that have been created by water erosion or compaction.
As it begins to flow under the slab, it exerts an equal pressure
on every square inch of concrete that the pump produces. Thus,
if the pump produces just 5 -10 pounds per square inch pressure,
it can easily raise the slab.
3.
Once the voids have been filled, the block will be pressurized
and begin to rise. Through precise placement of the holes, and
control of the amounts of material injected, the block will
be carefully moved into the correct position. Common applications
for Residential Concrete Leveling include: sidewalks, steps,
patios, driveways, swimming pools, garage floors, and interior
slabs. Concrete Leveling usually saves 50% to 75% over the
cost of removal and replacement.
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How
long has Concrete Leveling been in existence?
Accounts of raising large cement
slabs through the use of hydraulic pressure go back almost a century.
Mudjacking or Slabjacking has been in common use for about 50
years. Refinement of the process to its current state occurred
about 20 years ago when Grover Miller an inventor from Peninsula
Ohio, began working on A-1’s patented Self-contained pumping
truck, combined with a highly-dense crushed limestone material.
Generally
in Mudjacking or Slabjacking a portable pump is carried to the
location of the block to be raised. A hole of up to 3 inches
in diameter is drilled into the block. Varying combinations
of soil, sand, cement, or other materials, are mixed and then
injected under the sunken concrete block, causing it to rise.
Problems
associated with Mudjacking involve: containment of the mess caused
by excess mud or material in the area to be raised; drilling of
large holes that can weaken the block, and allow material to flow
too quickly causing cracking of the slabs.
Modern
Concrete Leveling techniques utilize smaller holes to avoid weakening
the concrete slab, or raising the blocks too quickly. A highly
dense crushed limestone is sometimes mixed with moderate amounts
of cement, and can be pumped slowly and safely through hoses that
are connected directly to the pumping truck.
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What
are the benefits of Concrete Leveling over replacement?
- The
cost of Leveling usually represents a savings of 50% over replacement.
- The
leveling process can be completed and ready for use in a matter
of hours
- Landscaping
and adjacent areas are usually unaffected by our process.
- Injection
of our materials help to fill voids and stabilize low-density
soils
- Leveling
maintains the uniform color of your concrete slabs.
- Concrete
Leveling reduces job time, energy utilization, and environmental
problems associated with concrete demolition, and disposal.
- No
Municipal Building Permits required.
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Can
any concrete slab or block be raised or leveled?
Generally, Yes. However when large
areas have crumbled or deteriorated, replacing the concrete may
be the only option.
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Our
concrete appears to have “raised up”. Can Concrete Slabs
be lowered?
Generally, no. However adjacent
slabs can be raised to “match and even” thereby eliminating
“offsets” or tripping hazards.
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Our
driveway is leaning toward the house, and water has appeared on
our basement wall. Water is leaking into our basement. Can our
cement be raised to direct water away from the house?
In
many cases we are able to lift the driveway or patio blocks to
allow the blocks to “pitch” away from the structure.
This method combined with caulking or sealing of cracks and joints
often improves problems associated with water seepage. Raising
concrete blocks will not completely solve water problems if footing
drains have failed, or other drainage problems exist.
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My
front steps have sunken, and there is a gap at the top. Can they
be raised?
Generally yes. There are some isolated
circumstances where steps cannot be raised. If the steps are made
of materials other than solid concrete or they are in a deteriorated
condition, they may not be able to be raised. It is best to have
your A-1 representative examine the steps to provide you with
a free quote or help advise you about your options for repair.
It is important to note that the gap at the top and sides of the
steps will usually not close. Most gaps can be sealed with polyurethane
caulking to resist water penetration, and provide an acceptable
appearance.
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Tree
roots have lifted my sidewalk. Can it be leveled?
When one or more blocks have raised,
the surrounding blocks can be raised to “even” the offsets.
This technique results in a gradual slope that will eliminate
the “trip hazards." In some cases however, the tree
roots lift the sidewalk too high to be properly evened.
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What
is a “Void”?
Voids are "pockets" of
air or water beneath the concrete. They are created by erosion,
poor compaction, or normal settling of clay or organic soils.
These types of soils can cause big problems for buildings and
concrete slabs. Concentrated loads, such as buildings or slabs
can literally squeeze air and water from soils. When this happens,
the soil sinks and the buildings or slabs follow closely behind.
Since voids cannot be seen, filling them is often quoted on an
hourly (Time and Materials) basis.
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How
long will concrete leveling or raising last?
Although every situation is unique,
concrete usually sinks because of water erosion, compaction of
soil underneath the slab, or movement on an incline. A-1’s
process of filling with an extremely dense material dramatically
improves the compaction of the underlying soil, however, some
soils i.e. peat contain high levels of organic material and may
be difficult to stabilize for long periods of time. Water erosion
is probably the most critical issue. Improper drainage, broken
or misaligned pipes or utilities, or surface cracks may allow
water to “undermine” the soil under the slab. With proper
drainage and sealing of cracks and missing expansion joints*,
leveling can last indefinitely.
*Polyurethane
caulking is highly recommended for most concrete applications.
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How
does Concrete Leveling compare in cost to other repair or replacement
options?
Concrete
Leveling usually saves 50% to 75% over the cost of removal and
replacement.
Please
bear in mind that if a partial replacement is done there will
be a variation in color between the new and old pours. With concrete
leveling, the continuity of color is maintained with the exception
of the small 1” holes used to inject the material.
Some
companies provide a “Grinding Service” for offsets or
“trip hazards”. Grinding exposes the aggregate within
the cement and results in an extremely noticeable difference in
color. A-1 does offer limited grinding services primarily for
commercial applications. Grinding can provide a cost-effective
option to leveling, if appearance is not a major concern.
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Will
the holes used in leveling be a different color than our existing
cement?
It is virtually impossible to match
the color of existing concrete. A-1 uses high quality mortar mixed
with the drilling material that we save from your existing concrete.
Over time, Due to weathering, sun, and other environmental discolorations,
our mortar will begin to blend with the existing concrete.
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How
do the costs of Concrete Leveling Companies compare?
In most cases the costs for Concrete
Leveling, Mudjacking and Slabjacking are comparable. It is
always our goal to quote a fair price for excellent work.
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Please
bear in mind that:
- A-1
has Local Ownership with the support and expertise of a National
Franchise
- A-1
uses Smaller Holes resulting in a safer, cleaner process
- Our
specially designed 5 PSI pump exerts less stress on your concrete
- A-1
has an exemplary record of honoring our warranties
- A-1
is a fully insured contractor
- A-1
uses State-Of-The-Art Equipment and Technology
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Is
Concrete Leveling a seasonal business?
Most of our work is done from April 1st
through the end of November. Since we use a material that is mixed
with water and pumped through hoses, our equipment is vulnerable
to problems associated with freezing conditions. We do provide
free estimates throughout the year.
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Why
does A-1 have a waiting list of 7 days to 3 weeks?
A-1 has gained an excellent reputation for
providing high-quality work, and honoring our warranty. Our reasonable
cost and the non-invasive nature of our process, has increased
demand for our services. As a result, we do have a 7-day to 3
week wait during most of the working season.
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Caveat
Emptor. Buyer beware of any Contractor who:
- Pressures
you to do work immediately or wants payment in advance of work
- Does
not put quotes in writing
- Is
not a member of the Better Business Bureau
- Does
not have local references
- Can
not provide you with proof of Insurance upon request
Remember:
The Better Business Bureau has information about most companies,
including non-members. Lexington BBB (859) 259-1008
BBB
Website: http://www.ky.bbb.org/
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