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A glossary for Mud Jacking Concrete

Limestone Slurry

The filler product we commonly use when we mud jack concrete is a ¼” down crushed limestone mixed on site with water to create a thick slurry. This product is then pumped through holes in the slab to fill any voids between the supporting base materials and the slab and to then also raise it by incremental amounts to the required level. Because the slurry always retains its volume (even after it dries) the lift is carefully regulated by the volume injected. After the lift is completed the slurry dries and hardens and provides permanent support for the slab.

The limestone used is an all natural, locally quarried softer (yellow rather than white) variety of the product with the additional chief characteristics for our purposes that it can be pumped under pressure and yet retains its volume once it dries and hardens. Other filler products such as chemical foams that rely on expansion to fill voids and lift the concrete are much less controllable and long lasting. The availability of this particular product in Manitoba makes us unique among mud-jackers around the world who typically must use combinations of sand, cement, silt or fly ash, all of which do not compare well with our limestone slurry as a slab lifting agent.

Mud-jacking (or mud jacking)

The term originally used to describe the process of lifting sunken concrete slabs by injecting common mud beneath the slabs to create the hydraulic lift required to raise the slab. It was an ingenious technique for lifting heavy street slabs and was first pioneered in the 1930’s in California. The key to mud jacking concrete is the hydraulic principle which transforms a small amount of pressure through a small hole to create a huge amount of lift by spreading the pressure over a larger area. For example, our limestone slurry pumped through a 1 square inch hole at just 30 pounds of pressure creates a lifting force of over 2 tons on each square foot of concrete surrounding that hole, easily and slowly lifting it as required.

Companies now using this technique commonly use the term “slab jacking” as mud is now rarely ever used as the lifting agent. In Manitoba, because of our significant presence in the marketplace we often hear the term “muddrucking” to denote this process. We kind of like that idea!

Job Performance Guarantee

The MuddRuckers job performance guarantee is easily summed up as: We don’t require any signed contract or advance payment and in fact expect no payment at all until we have fully completed the work as quoted. We want our customers to be completely satisfied with the work we undertake and we will go the extra mile to ensure they are. We undertake only that work we fully expect to complete to the reasonable expectations of the customer. Obviously, the very nature of our business is salvaging sunken, sometimes cracked, and often older concrete slab installations. In all those instances, that concrete can be restored to practical usefulness by restoring it to an original or higher level, to eliminate trip edges, to restore proper drainage and/or to fill voids which may result in subsequent settlement.


Specifically, our warranty states that “all lifted areas will remain in place (within ¾” of an inch) for 3 years or MuddRuckers will restore the lifted concrete to the originally restored level”.

Although all of our work is covered by our job performance guarantee which covers the initial completion of the work in the manner quoted there is always some risk that a lifted concrete slab may settle again due to sub soil shrinkage or compaction. Although the original base materials and our added limestone product will remain in place beneath the slab it is impossible to guarantee there will not be any additional compaction or shrinkage of the deeper sub soils upon which the level of any concrete slab is dependent. Sometimes foam injection companies will contend that they can provide soil stabilization to eliminate this risk. The truth is that foam products only penetrate the base materials which do not shrink or displace in any event but can not penetrate the clay sub soils which are the real source of future settlement risk.

Free Evaluation

As a part of the quoting process our Customer Service Reps will conduct an evaluation of the areas of concern reported by the Owner. We will include that evaluation in the “Site Description” portion of our quotation which describe the problem(s) as they now exist and will typically include our assessment of the reasons for that(those) problem(s). These evaluations will be quite concise and based on our extensive experience. They are the basis for our determination of whether or not we believe we can provide the right solution(s) and if so the resulting quotation for our services. We encourage any customer to contact the Customer Service Rep providing the quotation for further details or information regarding our evaluation and work recommendations.

Fixed Price Quotation

All of the work we undertake is based on a fixed price quotation provided to the customer. That quotation is provided by email or in hard copy and is signed by us and open for the verbal or written acceptance of the customer. Typically, our residential quotations, because of the seasonality of our work are applicable to the year provided but are open to acceptance in the following year if site conditions are substantially unchanged. A fixed price quotation means regardless of the work required to achieve the results specified the dollar cost will not change. Occasionally, more or less work and a corresponding cost adjustment may be agreed upon while on site or on some void fill jobs the price may be quoted in relation to the number of cubic yards of material used. All work is subject to GST but not PST.

Void Filling

Our limestone slurry has been found to be a perfect solution for filling hard to reach cavities below front steps and verandas or other locations that varmints like to hide out or flower beds keep eroding into. Typically, if we are raising a front sidewalk approach to the front step we will always fill the cavity beneath the step to prevent further settlement and erosion of base materials into that cavity. When filling voids beneath steps it is not necessary to fill the cavity within the step, just the cavity area below grade up to the underside of the step. Typically, if the area to be filled is visible we will estimate the amount of material required and provide a fixed price quotation for the work. Occasionally, if the size of the cavity cannot be reasonable estimated we will quote a base price inclusive of 1 cubic yard and an incremental price for each additional cubic yard required.

Frequently we are also contracted to fill hard to reach cavities on construction sites, behind grade beams, between buildings or beneath structural floors in commercial buildings.


Our equipment has been custom designed and built to suit the unique limestone material we use and the Manitoba conditions we encounter. Typically, concrete settlement in Manitoba is more dramatic than in most other locations due to a combination of climate conditions, heavy and difficult to compact surface soils and a thick layer of clay subsoils that are volume sensitive to moisture content changes. For these reasons the incidence of settlement is greater and average jobs require greater lifts than in other cities. Mud jacking concrete is how we get the required lift. Our large semi-trailer units with built in mixers, hose reels and hydraulic powered pumps enable larger payloads and longer pumping capacity to access most jobs directly from the street. The efficiencies provided by this equipment enables us to provide better service and also keep our customer costs low.

CCCP (centrifugally cast concrete pipe)

A newer and usually more cost effective alternative for relining larger diameter CSP, brick or concrete culverts, storm sewers or other infrastructure installations. Also called Spin Casting. Just like the CIPP (cured in place pipe) and slip lining alternatives it does not suit every situation but is often applicable in situations they are not. MuddRuckers is the licenced applicator for this process throughout Manitoba, Saskatchewan and NW Ontario. For a more complete description of the CCCP process and its advantages follow this link to APM, the originator and licensor of this process.


Our company has implemented and regularly updates and improves on a comprehensive Safety Management System. This system was implemented about 15 years ago and has become the basis for securing and maintaining our COR (certificate of recognition) from CSAM (Construction Safety Association of Manitoba). We have also secured the equivalent certification in both Saskatchewan and Ontario for mud jacking concrete and infrastructure projects undertaken in those jurisdictions.