Any successful slab lifting job begins with a thorough site evaluation. A site evaluation is not limited to, but should include Identifying the Cause of Slab Settlement, Gathering Information, Identifying Potential Hazards, and Visualizing the Mobilization.
Cause of Slab Settlement
Determining the cause of settlement is usually the first step in beginning our evaluation. The cause can be any number of things such as erosion, ground water, sink holes, poor compaction, and buried debris that breaks down over time. Correctly identifying the cause will help us determine if slab jacking alone will solve the problem or whether a combination of lifting, stabilizing, and / or void filling will provide the permanent solution.
The next phase should include gathering information from multiple sources. This includes dimensional information such as length and width of the slab; but also, the amount it has dropped, to help determine the volume of structural foam needed to lift the slab back into place. We also gather information from the property owner; finding out about any known irrigation, electrical, water, or drain lines. Specifically, we find out from the owner about any areas or features that need protecting around the injection site, the location of our rig, and all points in between where our crew may be working.
Identifying Potential Hazards
If the job is outside of a building, we find out where the utilities are and have them professionally located. Additional information that may be available could include a soil engineering report, a structural engineering report, and reports from the builder of the structure. We also consider other issues that might create problems like slabs binding (concrete saw?), bent rebar from a settled slab, etc.
Visualizing the Mobilization
After the data gathering is complete, we visualize the job site as a whole and consider any challenges to mobilizing and physically reaching the areas that need lifting. We consider the size of the rig we're using on the job compared to the site size, the amount of pump hose we'll need to reach the lifting points, the power we'll need, etc.
Some of the above seem obvious, but it's often the obvious things that get overlooked by the common contractors out there. Mistakes can drastically affect the cost to the property owner, in terms of both time and money. There's a reason why highly skilled airplane pilots go through the same checklist prior to every flight. Sometimes you only get one chance to choose the right contractor.