slurry and foundation repair

What is Slurry and How is It Used in Foundation Repair?

You keep hearing the term *slurry* from a potential foundation repair contractor and you’re a little *fuzzy* on what that means. You’re pretty sure it doesn’t have anything to do with people speaking unclearly . . . but what does it have to do with foundation repair?

Anchor Foundation Repair Bryan College Station

At Anchor Foundation Repair, we use slurry every week to repair slab foundations. Slurry is also used in some of our other services for concrete leveling and under-slab tunneling. We haven’t been trying to become slurry experts on purpose, but after 35+ years of working with it, it just kinda happens. . . 

This article will explain what slurry is and what it can do for your home. Then we will discuss slurry’s specific use and benefits in the drilled-pier foundation repair process. Let’s get started!

What Is Slurry? What is Slurry Used For?

slurry and foundation repair

Slurry is a mixture of topsoil, Portland cement, and water. Specific to our area, we use a Brazos River topsoil that is sifted and fine-filtered before mixing with the cement and water. The topsoil choice would be tailored to your area if you’re not here in the Brazos Valley.

If slurry sounds a little bit like mud, that’s because it IS a little bit like mud. The consistency of the slurry is different depending on its purpose in the repair project. The slurry is made thinner and more watery for filling purposes and thicker and with less water for lifting purposes.

We’ve already mentioned that slurry is used in foundation repair, under-slab tunneling, and concrete repair. So in foundation repair and under-slab tunneling, slurry is used as a filling material and is of a thinner consistency like pancake batter. In concrete repair, it is used as a lifting agent and is more of a cookie dough consistency. Is anyone else getting hungry?

We’ve got articles on slurry used in under-slab tunneling and slurry used in concrete repair if you want to check those out. But since this article is just about how we use it in foundation repair, so we’re gonna stay focussed on that.

How Slurry is Used in Foundation Repair

Slurry is used in foundation repair as a finishing step in the drilled bell-bottom pier repair method. This step is called mud-pumping and it is commonly used with drilled piers. Mud-pumping is used to fill the void under your home created by raising the slab-on-grade foundation to its proper elevation.

What happens in foundation repair is that your home has sunk and needs to be lifted back up. The home and the soil underneath your home have settled and caused foundation problems. 

void under raised foundation

Once the home is raised during the foundation repair process, there is now some empty space between the majority of the underside of the foundation and the ground (except where the piers are holding it up). Mud-pumping this void under the home with slurry will fill up that space completely. Filling this void provides support to the entire slab as it was designed and constructed to be.

Slurry is pumped under the home by some temporary piping laid in place by the foundation repair team. They use a hydraulic pumping machine to pressurize the slurry and inject it under the home through these pipes. Then the temporary pipes are removed. The slurry dries to a hard sandstone-like texture that is very strong and can bear considerable weight.

Benefits of Slurry in Foundation Repair

Mud-pumping slurry to fill the void under your raised home has many benefits. The first is that it fills that space up with something. If it isn’t filled with something purposeful, it can get filled with other undesirable things, like water or critters, or both! 

But the *most undesirable thing* that space can get filled with (if it’s not filled with slurry) is your foundation settling into the space again. Not filling that space with something like slurry, is practically an invitation for your foundation to settle again into that void . . . 

Speaking of water under your home, if that void under your home fills with seeping water, then erosion can occur which leads to more settlement. We don’t want that, right?! So the use of slurry mud-pumped under your home helps to prevent erosion and washout.

mud pumping slurry

Preventing erosion, washout, and filling the space for extra support under the entire surface of the foundation ultimately helps to minimize the opportunity for future settlement of the home. In other words, filling up that space and giving the home more support is the best way to lock in your foundation repair and make it as secure as possible.

Maybe another way to think of it is this: you’re packing a box to send in the mail. You fill the box with whatever item and then add some padding but not enough to fill the box entirely. The top surface of the box represents your foundation.

If you leave a void of empty space inside the top of the box, then the box can get crushed and smushed in the mail. Filling it up completely is the best way to keep your items safe, secure, and help them stay in place during shipping.

The same is true for your foundation repair in a sense. Leaving the void empty opens up opportunities for things to go wrong. And filling that void can avoid them. See what I did there?

We choose to fill the void under your raised foundation with slurry because we think it’s the right thing to do to make your foundation repairs as effective as possible. Not every foundation repair method or company takes this extra step.

What Else Makes Drilled Pier Foundation Repair Effective?

foundation repair and slurry

Besides slurry, which you now know is a great void-filler under a raised slab, what else about our drilled pier foundation repair is different than other methods?

At Anchor Foundation Repair, we have been fixin’ Brazos Valley foundations since 1985 and drilled piers are the only piers we use for slabs because they are your best chance at minimizing future settlement in your home.

Mud-pumping with slurry is one of the things that makes our repair method stand out from other companies. Check out what else we can do for your foundation with 4 Service Features that Set Anchor Foundation Repair Apart from other companies.