Is Mud Pumping Necessary?

When a homeowner begins to look into the problem of foundation damage, several questions usually arise. At some point, the term “Mud Pumping” is likely to come up. But what is it, and is it necessary?

Getting the facts is vital to making wise decisions for your home. Foundation damage largely results from changes in soil moisture that causes soil movement under your home’s foundation. When this shrinking and swelling of clay soil occurs repeatedly over time, the strain placed on the concrete slab leads to damage to both the foundation and the home. When the foundation is damaged, gaps and voids can be created under your home, and mud pumping is a part of the repair process.

Repairing the concrete slab foundation involves supporting and leveling the slab. Most of the focus, rightly so, is on the foundation. When portions of that slab have cracked and collapsed (settlement) they must be raised and supported, and often a substantial void is created between the bottom of the foundation and the soil. This is now an open air pocket under the foundation and nothing is supporting the majority of the foundation above. If repair efforts are stopped with the slab only, the repaired and leveled foundation will have to “bridge” these voids with no support. A residential concrete slab foundation was never designed to function as a bridge. Foundations are engineered to rest on level soil. Mud pumping fills these voids by pumping a mixture of soil and cement – “mud” – under the newly leveled foundation. Both the foundation support system and the voids must be addressed to ensure that your home is secure and stabilized.

Most foundation repair companies will NOT complete the job with mud pumping, and it’s important to insist on this step for your home. Mud pumping is expensive for the repair company, as the machinery involved is more expensive than any other equipment in the repair process. There are additional elements of time needed to perform the mud pumping, too. And, the homeowner may be asked to take certain protective steps like turning on flowing water, running washing machines, etc. to avoid clogging in the pipes. However, mud pumping will avoid additional repair needs at a later time, and it is well worth the extra time and investment. Many companies will try to suggest that this is an optional service, but that would be a mistake. It may be a bit more time consuming to complete the job, but an incomplete foundation repair makes little sense when so much is at stake in your home.

All of our foundations are at the mercy of the weather. We cannot eliminate the risk of soil shrinkage during extreme heat or soil expansion during heavy periods of rain.  However, we can understand how it affects our home’s foundation and take steps to avoid damage.

Dawson Foundation Repair services homes and commercial businesses all over Texas including Austin, Plano, Dallas, Houston, San Antonio, and other smaller cities. If you have questions about the stages of foundation repair, or you know that you have existing foundation problems, we are here to provide you with a professional opinion, and if necessary, a proven, time-tested, and permanent house leveling solution.

5 thoughts on “Is Mud Pumping Necessary?”

  1. William H Fennelly

    I have a report that states the home needs 20 piers.
    1 story home with concrete slab 40 x 50 (about 6 inches thick). Sloping down to front of house at 5″
    Approx cost please.
    League city, Texas

  2. Hi, William – We’ve sent your question and contact email to a representative who can help you. You should be hearing from someone soon. Thanks!

  3. We had a structural engineer inspect our slab last week. He advised that when levelling the foundation, we should not fill any voids under the slab via mud pumping. I asked for clarity around this and he said that if a part of the soil under the foundation was to swell, the foundation could heave and you would have to level the lower areas of the foundation again. Just wanted to check if you have ever run into such an issue?

  4. Yes, I have run into this issue before. I respect structural engineers because they are the engineers who have studied and trained to design and understand structures and foundations. However, in this instance we have a difference of opinion. I would like to make a couple of statements and then share my 29+ years of construction experience.

    First, when a concrete slab foundation is constructed it is poured over compacted dirt and there are no voids. The compacted dirt provides the support for the foundation. Second, a critical part of the original foundation repair process designed by FHA / VA engineers does include filling voids after raising / leveling a concrete slab foundation.

    Leaving a void under an interior portion of a concrete slab is simply leaving that area unsupported. If it is unsupported then it is susceptible to “sinking.” I have seen hundreds, maybe thousands, of concrete slabs that were left unsupported in the interior and subsequently settled. Our solution is to provide the support which is missing. We install Bell Bottom Piers and then fill the interior voids with a special soil/concrete mixture referred to as “mud.”

    Most foundation repair contractors will not “mud pump” the interior voids of a home. These contractors feel that mud pumping is not profitable and choose not to invest in the equipment. They are hoping for the best.

    Most foundation damage and repair occurs around the EXTERIOR perimeter of the home because that is where the expansive clay soils are most vulnerable to changing weather conditions. Usually what happens is that a large area of soil loses significant moisture through plant/tree withdrawal and evaporation during hot, dry weather. When the clay soil loses large volumes of water it will shrink and pull away from a portion(s) of the perimeter foundation, leaving it unsupported. This part of the perimeter is literally “hanging in the air” and when the area becomes too large the concrete foundation will crack and collapse until it reaches something that will support it, which is the shrunken soil.

    Martin Dawson, owner

  5. Thanks for your response and all the information you provide on your website. It’s really helpful in determining next steps to address our foundation concerns.

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