Floor joints are a vital consideration on any concrete slab. But aside from their massive benefits, their installation requires coordination between the contractor and customer. And the material needs to be determined based on the environment of the area.
Firstly, why would anyone install joints into a nice new concrete slab? Well, there are many reasons. And the biggest is to allow the concrete some room to flex. And it doesn’t seem like a large, rigid concrete slab should flex. But when it’s sitting on top of a settling ground, enough tension could easily build up, so that the slab actually cracks under its own weight. And a cracked foundation has the potential to cause a lot of harm to a building in the future.
So the ideal scenario is to install joints immediately after the slab is poured. And after 28 days of curing, the concrete will be ready to cut. But there are different types of joints that a floor installer can cut. But the most common is a control or expansion joint.
The control joint’s purpose is to predetermine where a crack may occur on a concrete slab. And the best way to do that is to create a weak spot on the slab by cutting a 1″ deep groove. This groove creates a weak spot in the concrete, which can then be used to control where the slab may crack.
The expansion joint is a little different. It is cut all the way to the base of the slab. So its depth will be as deep as the concrete slab is high. The purpose of these joints is to accommodate the expansion that might occur during thaw and freeze cycles. By allowing the concrete to flex with the movement of the ground, the concrete can shift at the pre-cut areas, instead of spider cracking throughout the slab.
But What Joint Material Should I Use?
And this is a phenomenal question. And the answer depends on how the area is being used. If it’s a lot of industrial traffic, from fork lifts, loaders, hoppers, and other heavy duty machinery, then you’ll want a material that is strong and rigid. A great example is Spal Pro’s RS88. This material is a polyurea joint filler. The benefit of this is that it gets hard. And the reason a plant or facility owner would want a hard material is so that the forklifts and hoppers don’t press stones or nails or other items into the joint material.
And not only does it get hard, but it can also be installed in temperatures as low as 32 degrees F. So after you’ve checked the floor temperature with your industrial thermometer, you can rest easy knowing that there is a joint material that can be used in most situations.
But the compromise with being so hard is that it doesn’t offer as much flexibility as some polymer joint fillers. Polymer joint fillers, such as urethanes or epoxies, are best used when only dealing with foot traffic. Because a fork lift can easily force a stone or screw into the material, causing it to rupture. And a ruptured joint is about as practical as not having any joints.
Overall, joints are a necessary caveat for any commercial or industrial facility. However, determining which joint material to use depends ultimately on how much traffic the area receives and what type of traffic the area is receiving.