Void filling & prevention – Slabjack Geotechnical

Most concrete will develop void space under it at some point. Often nothing happens, at least for a while. Eventually though, either cracks develop or settling happens so doing something sooner rather than later will help preserve your asset.

We see voids on all kinds of jobs. Against foundation walls, under driveways at broken control joints, anywhere downspouts drain, against pool walls, all sorts of places. We had one I vividly recall, dogs had burrowed out a den under a patio. It was quite a dwelling! It went back about ten feet and must have been close to two feet tall. I imagine they were none too happy to have lost their lair!

In the past, voids were primarily dealt with by shoveling dirt or gravel under as best we could or pumping concrete into it and hoping for the best. Today polymers have, to a large degree replaced those earlier methods. The reason for this is twofold; first, injecting liquid polyurethane into a void space is a very efficient way to fill a cavity. Secondly, polyurethane foam is an extremely rigid but also very light material. Varying from a half a pound per cubic foot on up to several pounds per cubic foot, polyurethane foam provides easy cavity filling but also structural stability. For example our eco-rise 3.5 supports roughly 80 pounds per square inch. In other words a square foot of this material will support about 12,000 pounds all while weighing 3.5lbs per cubic foot!

So how do you tell if you have a void under your concrete? Unless you have access to ground penetrating radar the two primary ways voids are detected are through “sounding” and visual inspection. Sounding consists of tapping on the concrete or pulling a heavy object across the concrete. Where voids are, a hollow sound can easily be heard. Visual inspections and probing are helpful to determining the extent and the starting point of voids. Visual inspections are most often performed along foundations were concrete meets a foundation wall. Most often porches, patios and sidewalks. Once voids are detected an estimate is presented to fill the voids and to correct the cause of the void. Most often this plan would consist of void filling, caulking cracks and joints and moving downspouts.

Slabjack Geotechnical takes great pride in our void filling and prevention services. We seal many thousands of feet of joints and cracks every month and we have the tools and products to do a long-lasting job.

Whether yours is a small void or hundreds of cubic feet Slabjack Geotechnical can take care of your void problems, call today.



Superior technology, Superior polymers, Superior results.





What to expect during an estimate – Slabjack Geotechnical


Working with contractors is too often frustrating.

Here are a few things to expect when dealing with Slabjack Geotechnical.

We have a dedicated office staff that works Monday through Friday 8-5. If you don’t get a live person on the phone when you call it’s because they are with other clients. So leave a message and we will quickly get back with you. Our appointment center is responsible for collecting all of the information that the estimator needs to provide an exact quote the day the estimate is given. They are not however technical experts on the concrete raising side of the business. If you have technical questions they will get the information needed and one of our production foreman will return the call at the end of the day.

We have dedicated estimators who work and live in the communities we serve. They are scheduled to meet with customers and to discuss any concerns and answer any questions they might have about the process such as the cost, how long the job will typically take and what results are to be expected. Our estimators are trained what to look for in the bidding process however they are not experts on the production side of the business and occasionally they too will forward questions of a technical nature to the production foreman who will consult with the estimator prior to a formal bid being produced.

We have three experienced production crew foreman who have worked many hundred’s of jobs both residential and commercial as well as municipal work. These jobs range from simple sidewalk leveling to basement floor void filling and raising, commercial and industrial warehouse floors and municipal buildings and pools deck leveling and stabilization.

What all of this means is we have a streamlined process from initial call, to the formal estimate, to the work being performed, to invoicing and if necessary warranty work. Each step along the way we want you to feel comfortable and that you’re going to be well taken care of. We are serious about our reputation, we aim to be the best Slabjack contractor and we’re going to do that the old-fashioned way with great service and integrity.

Call today, 1-855-752-2522

Superior technology, Superior polymers, Superior results!

Why should you caulk your driveway joints and cracks? Slabjack Geotechnical

Concrete driveways are large initial investment, it makes sense to maintain them to avoid costly repairs. One of the most cost-effective things you can do to keep your driveway looking great is to caulk all of the joints and any cracks that develop. Cracks, either by themselves or simply in the control joints allow water to erode the supporting soils under the slab. This erosion leads to cracking and/or settling. In addition plant growth, access for burrowing insects such as ants and other critters further creates problems.

A bigger and bigger part of our business has become preventative maintenance and this includes caulking many thousands of feet of cracks and joints every year.

When we are called out to do an estimate the estimator will present an offer to raise all of your settled concrete and he’s going to provide an estimate to seal up all of your cracks and joints. In addition we are going to be looking for evidence of voids under your concrete slabs. These voids often develop along foundation walls, at control joint junctions in your driveway and around vertical support walls such as around pools. We search for these voids because where voids are present cracked concrete or settled concrete is sure to follow. So in addition to providing an estimate to raise your slabs and caulk the joints we may propose to also protect your existing concrete that hasn’t yet settled, but likely will because of voids, in the future.

We present you with all of our best solutions and allow you to make the choice thats right for you.

Call today 1–855–752-2522


Superior technology, Superior polymers, Superior results!






What to do about cracked and settled concrete – Slabjack Geotechnical

One of the things we often come across when doing an estimate for settled concrete is cracks, sometimes a lot of cracks. People ask “is there anything that you can do with these cracks”

The simple answer is “yes, but” the “but” being what is your end goal? If the goal is to make the crack invisible there’s nothing that can be done short of a complete overlay of the slab to fix the crack and even then slight cracks will often remain. Decorative overlays cost in the neighborhood of $4 to $12 or more a square foot. On the high-end $12 you can generally get brand-new concrete poured of course it won’t have that fantastic decorative look of an overlay.

The fix that we most often recommend is simply caulking the joint or crack with a material that closely matches the concrete or that will be sanded or textured too closely match the concrete. This works best with joints due to the fact that they are nice and straight and not jagged and of various wits and depths like cracks are.

Here at Slabjack Geotechnical we primarily use a custom formulated silicone caulk for concrete however if we are removing previously installed polyurethane we generally will use polyurethane again since it sticks to itself so well.

Take a look at our websites before and after pictures. We try to update it every few months with new projects and this winter we will be adding a lot more content relating to caulking since so much of our work revolves around it now.

Call today for a no-cost no obligation estimate,


Superior products, Superior polymers, Superior results.