featuredVoid filling & prevention – Slabjack Geotechnical

September 23, 2016by Jerald Sargent0

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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.



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