Foundation, Concrete and Earthquake Engineering

Mud Pumping During Foundation Repair

Mud Pumping is the process of filling voids under concrete slab foundations, patios, pool decks, and driveways. There are several similar terms used to describe similar processes. Mud Pumping, mudjacking, slab jacking, concrete pumping, and pressure grouting all refer to similar but different processes.

Mudjacking and slab jacking are essentially the same process of pumping concrete or a concrete/mud mixture into voids underneath a concrete slab in an effort to raise the slab. Usually this works with smaller slabs such as driveways and patios. It is far more difficult and complex to raise a concrete slab foundation and the entire attached commercial building or home with this method. Concrete pumping is a similar process but it may use a high or low strength concrete. Mud pumping and pressure grouting refer to a process of simply filling voids underneath a concrete slab foundation without trying to raise the foundation or structure. This will give the foundation the support it needs between itself and the ground. Usually the commercial or home foundation will have been raised, stabilized and leveled by a repair contractor prior to the mud pumping or pressure grouting.

When there has been an imbalance in the moisture in expansive soils then the concrete slab foundations that rest on top of the soil will experience movement. The movement can be lateral, upward or downward. One example could be a group of shrubs or large trees on one side of a home that is absorbing large amounts of water around and under a portion of the foundation. The expansive soil in this area will shrink relative to the soil in other areas under the foundation because it will have a lower water content. When the soil shrinks too much it will lose contact with the foundation and the foundation has lost its support in that area. If the area is too large then the weight of the building structure and foundation will cause the foundation to crack and "fall." That series of events will cause structural damage to the commercial building or home and may necessitate the need for home foundation repair or commercial foundation repair.

Many times after the leveling process has been completed for a home foundation or commercial building foundation there will exist voids under the foundation. A concrete on slab foundation was never designed to be a "bridge" and support weight between two support points. This type of foundation was designed to rest on the soil underneath and the soil provides the ultimate support for the foundation and the attached building or home. Therefore the repair contractor should fill these larger voids so that the concrete slab foundation can "rest" on the ground.

Regardless of the reason for the void under the home foundation, mud pumping should be used to fill any large voids with a low strength cement or a slurry of mud and cement. If interior bell bottom piers were installed then they provide easy access to the area of the void. Sometimes one inch holes will be drilled through the slab to allow access to the area of the void. Then the slurry will be pumped under pressure into the voids. At this time all of the water faucets in the home or the commercial building should be turned on to keep a stream of water flowing through the sewer lines. Toilets should be flushed periodically and the washing machine should wash some clothes. This will prevent the slurry from clogging any sewer line that may have a crack or break prior to or during the leveling process.

After the mud pumping process has been completed and the slurry has hardened the work crew will pack the remaining openings in the interior portion of the foundation with a select fill dirt. The openings will then be covered with a layer of plastic sheeting to help prevent moisture from seeping into that area. The area will then be patched with new concrete. The patched area will be smoothed and allowed to dry for a number of days. Outside piers will be packed with sand and/or topsoil. The commercial or home foundation repair job is now complete and the property owner can feel comfortable that this solution will last the life of the property structure.


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  2. Nice article. Thanks for sharing.
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  3. This blog is help for us..But as per these misconceptions.I ll recommend that any one who planning for foundation repair .Should hire foundation repair professionals