FAQ'S - Frequently Asked Questions
Mudjacking or slab jacking is a very precise method of concrete repair when sunken, uneven concrete is the problem.
The concrete needs to be sound. A few cracks are okay and will not hamper repairs. Mudjacking can raise and level just about any concrete pad, driveway, floor, sidewalk, walkway, porch or patio. It can raise and level any concrete structure such as poured concrete steps or stair.
How much money will I save?
Approximately 60% to 80% over replacement of the concrete.
How long does Mudjacking take?
Most jobs are done in less than 3 hours due to our experience and efficient equipment.
Will my yard or sprinkler heads be damaged?
No damage is done.
When can we drive on the driveway?
The same day.
Will I see any movement after the work is done?
Sometimes the ground shrinks and the possible will settle up to 1/2 inch in the drier months of the year. This is moisture related and nothing can prevent it.
How much room do you need to work?
3-4 feet from the perimeter if working inside.
Is your work dusty or loud?
The drill creates a small amount of dust and our equipment is powered by small gas engines.
Will my concrete crack?
Sometimes old cracks that occurred while it was settling will open and new cracks may occur depending on the strength of the concrete, the amount we need to move it and the amount of steel used in the concrete.
Will the patched holes match my existing concrete?
We will not be able to match perfectly, but get as close as possible.
In detail, what is mudjacking?
Mudjacking is the process of pumping a water, dirt and cement mixture under a concrete slab in order to lift it. This mixture is called slurry. The exact ingredients vary from company to company, and from job to job. Mudjacking can be the solution to many homeowners' sunken concrete problems including stailizing slabs that have voids. It may also be called concrete leveling or slabjacking.
Concrete can sink or settle for several reasons. If the original concrete was installed on dirt that had not been compacted properly, the slab will start to settle within a few years. Once the concrete does start to tilt or sink it can cause walking hazards, unwanted water runoff, or major foundation issues.
There are several factors to consider when choosing a mudjack contractor. The first step is to have a contractor come to your house and determine if the concrete slab is a good candidate, be very skeptical of telephone estimates. A concrete slab must be intact, in good shape and at least 30” wide to be a possible candidate. If a slab is broken into small pieces it is best to have it replaced.
Concrete begins to get softer or weaker as it becomes old. There are some exceptions but usually concrete over 30 years old should be replaced.
Most residential concrete is poured 2,500 PSI (pounds per square inch). The higher the P.S.I. the stronger the concrete is.
Mudjacking starts by drilling a series of holes through the concrete slab. The size of diameter varies with different contractors. Ours is 1 3/4" diameter hole and these holes are approximately 3' - 4' apart from each other.
Next we hydraulically pump a soupy slurry into the holes. Each contractor has his own mix for making the slurry. Once the void is filled under the slab, the slab begins to raise up to its’ proper elevation. Often there are voids under slabs that need to be filled to stabilize the concrete without raising the slab.
The most important part of mudjacking is to make sure the voids under the slab are filled in. There are contractors that have undersized equipment (not enough material). Sometimes slabs are raised on collars like ant piles, leaving voids. This method takes about half the material to raise a slab and gives the industry a bad name. Because the job is only half done, it will fail in the future. Be careful about choosing the lowest estimate, you may get what you pay for.
After raising or stabilizing a slab it’s time to plug the holes with cement. Not all contractors take time to do a good job.
We use a portable pump so we can custom make each batch of material for its’ proper thickness. Our portable has a short hose so we can change the thickness at a moment’s notice. Some contractors pump slurry from the street making it much more difficult to control the thickness of the slurry. Having the wrong thickness in a hose can leave the operator wondering when the proper thickness will arrive which can be very problematic.
No mudjack contractor will guarantee they won’t crack the concrete slab when raising it. Using the proper thickness of slurry greatly reduces the chance of cracking the slab. There are other factors that are out of our control that can cause a slab to crack.
Keeping a good sealer on the concrete prolongs the life and look of the concrete. Putting the sealer on helps prevent the concrete from pitting or what is called spalling (when small pieces of the surface come off). Mudjacking can save up to 80% compared to replacement cost.
Winter is not a great time to mudjack. With the temperature being around 30 degrees, it can cause ice on the concrete, which in turn can cause accidents. When the ground is frozen it holds the concrete and won’t release it until temperatures rise in spring.
Good Reasons to stay away from raising concrete slabs with foam:
If foam was a good source to use as a sub-surface under concrete, all concrete contractors would use it prior to pouring concrete; They don't.
No concrete raising method can guarantee a lifetime of use without the risk of the concrete re-settling. Foam under the slab makes it problematic to re-raise a slab.
Raising a slab with foam requires a chemical reaction. If a slab is "hung up" on a foundation wall or an adjacent slab, the slab you are raising will break or crack.
Good luck finding a structural engineer who will recommend foam over a good earth based slurry for raising concrete slabs or stabilizing.
Basic physics imply that a heavy, dense foundation can support a heavy concrete slab better than a light, air filled foam that is man-made.
Foam breaks down in time. A good, earth based slurry can't.
Conclusion; After raising slab, existing cracks may re-open and new cracks may appear. Concrete slabs may resettle when using foam.