Tuesday, July 21, 2009

What are Voidfilling and Mudjacking?

Mudjacking

Mudjacking is an additional foundation repair technique used to fix sinking and shifts in flat concrete areas. The process uses pressurized mud rather than piers. The mud is typically comprised of sandy loam soil, water and some cement for stiffness. The mixture is pumped under the foundation through a hose until the void is filled and creates lift of the desired areas.

Ace Foundation recommends mudjacking only for flat concrete surfaces such as garage floors, driveways, pool and patio decks.

We do not recommend mudjacking for the lifting of structural load bearing foundations/surfaces for the following reasons: The performance depends on the soil beneath. The lifting process may break sewer pipes and quickly fill them with the mud, requiring expensive plumbing repairs. A uniform lift is very difficult due to the different weight and thickness of the slab.

Many foundation repair contractors, as well as structural engineers, like to use piers on the perimeter grade beams to repair failed foundations and to use mudjacking on foundations with interior failure such as sinking or sagging floors.

Mudjacking is a procedure which involves drilling two inch (2") diameter holes through the floor in the affected area, bringing in a hose, about the size of a firehose, with a nozzle that fits in the holes and pumping a thick mud grout under the floor. The grout is typically comprised of sandy loam soil, water and about twelve percent (12%) cement.

The grout is pumped under the foundation with several hundred pounds of pressure until all voids are filled and the back pressure lifts the foundation to where it needs to be.

Mudjacking has been successfully used to lift streets, porches, and driveways at a cost much lower than replacement, but Ace Foundation does not recommend the use of mudjacking on homes or buildings for several reasons.

One big reason we do not recommend mudjacking is that the process cannot be fully controlled by the contractor once the grout leaves the nozzle.

The grout always takes the path of least resistance, which means once it leaves the nozzle the grout can come up through bathtub, leaveouts, shallow areas of concrete flooring, etc. The main danger that the mudjacking process poses is to plumbing under the foundation. As the back pressure increases, the foundation begins to raise and the possibility of plumbing lines separating increases. The moment a sewer line breaks, the grout starts entering the line and the cement can set before a plumber can clean it out. Once the grout sets, the plumbing line has to be broken out and replaced.

Mudjacking also tends to be a temporary method of repair. In order for the grout to hold the foundation in position it depends on the soil beneath it to remain in place. If the soil moves due to loss of moisture then the grout will not be able to hold the load.

Ace Foundation installs STEEL INTERIOR PIERS and accomplishes all lifting with them. We then have a plumber test for leaks in the plumbing lines and the home owner has the opportunity to repair the leaks.

We then fill the void between the floor and the soil with the same process as mudjacking yet with pressure and grout that are safer for the plumbing. This approach allows Ace Foundation to control damage and to provide the home owner with a longer lasting repair.

Voidfilling

If the lift of a foundation creates a void under the slab's interior, then we use a technique called voidfilling. Voidfilling is basically the same procedure as mudjacking but with some key differences.

  • We do not mix cement in our mud for voidfilling.
  • We only use light pressure to pump the mud into the void.
  • The foundation load is carried by our piers and not by the mud.
  • Mudjacking carries no warranty, but our steel piers do.
Get more information by visiting www.AceFoundation.com.

1 comment:

  1. It's interesting that the grout is made up of sandy loam soil, water, and 12% cement. This mixture, when shot through the 2" drilled holes can help fill the voids and lift a concrete slab. My parents have a walkway that's starting to get uneven. It sounds like mudjacking might be a possible solution. They were worried that they'd have to tear out their entire concrete walkway. http://www.crackerjackmudjacking.com/mud-jacking-101

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