When choosing a polyurethane foam slab lifting contractor, it’s important to make sure they have a thorough understanding of industry best practices. There are a great number of details to be aware of, but they’ve become second nature to us over time. Why? Because we care about your property.
For simplicity’s sake, we’ll divide the best practices of slab lifting into three sections:
- Lifting the Slab
- Wrap Up
Let’s start with the very basics. When we arrive on the site, we double-check location of buried utilities and other underground infrastructure. We always make sure we have a thorough understanding of the subterranean layout before we begin. Another essential preparatory step to evaluating a job site is to document the existing conditions of the site. Aside from lifting your slab, we want to do our best to leave it as it was before we arrived.
Polyurethane foam, once cured, is VERY difficult to remove. That a testament to its strength and binding qualities, but can be quite a pain if a careless contractor accidentally splatters some on your property. That's why we make sure to cover any critical property that can’t be moved out of the way. For example, if we’re lifting a warehouse slab next to heavy machinery that’s secured to the floor, we'll cover the machinery in plastic.
Lifting the Slab
The first step in the slab lifting process is to make sure that the slab can be lifted. In other words, we check the joints around the edges, where the slab connects to walls or other slabs. We make sure they’re clear and the slab isn’t fused to those other objects. In many cases, we may need to either saw cut some joints or clean them out with a sawzall or a trowel.
Next, we'll set up a measuring device that accurately indicates when and by how much the slab lifts. Now it’s time to lay out the drill holes. Each slab is different, so we consider very carefully where stress points may occur under the slab as we inject the expansive foam. A gradual, measured approach is always best.
Before we begin work on each section of the slab, we spray Spetec Surface Guard along joints and around the outside of drill holes to prevent foam from bonding to the concrete surface in case it ends up overflowing into those places. This is a critical step, since – as mentioned earlier - it’s very difficult to remove foam once it has cured. While injecting, we use longer shots to move the material out wide and fill voids, and use shorter controlled shots to get foam to cure right beneath drill hole area and lift.
While injecting polyurethane foam, we always maintain a 360 degree field of awareness. We never try to lift the entire slab from one drill point. Smaller injection amounts, spread across many drill points will lift the slab smoothly and gradually.
After leveling and/or stabilizing the slab, we trim all excess foam that has eased out from underneath the slab. We sweep up any cured foam bits, concrete dust, etc. Our goal is to leave every site in better shape than we found it!
When choosing slab lifting contractor, make sure they care enough to follow these industry best practices and you'll be one step ahead in your decision process!