Whenever dealing with concrete, there are always going to be floor joints. But how do you deal with joints when sealing the floor becomes a priority? Well, here are some of the most common methods for how to deal with concrete joints.
First, you should know which type of joint you’re dealing with.
There are a few different types of joints:
- Isolation Joints – these joints occur at the perimeter of the slab and where there are openings to allow for columns. This joint’s depth is the same size as the thickness of the joint. This allows the slap to move independently from the walls or column of the facility.
- Construction Joints – these occur in the slab because of the limits placed on the size of the pour. Like isolation joints, construction joints are the full thickness of the slab, and they are also bounded by removable or permanent forms, like rebar or dowels.
- Control Joints – These are cut into the top part of the concrete slab. They are usually about 1/2″ or 1″ deep. Their purpose is to create a weekend plane, predetermining the location of a natural crack cause by shrinkage or settling.
- Expansion Joints – Expansion joints are used to isolate two structurally independent portions of a building, such as a low rise wing adjacent to a high rise tower. The joint is formed with the slab, and once set, filled with an elastomeric material
And all these joints are regularly seen from floor installers. However, the most common joints are the control joints. And there are a few ways that floor installers can handle joints:
- fill them in with epoxy or urethane cement
- sometimes an owner will want a completely, smooth and seamless floor. These requests aren’t uncommon. But when their desired floor covers the span of a bunch of control joints, it can become difficult to achieve this. So the best course of action is to prefill your joints. Urethane cement is usually an easier material to fill with, because it’s heavier. But epoxy can work too if you mix it with enough sand. But epoxy usually needs an additional coat, or else it may sink, and telegraph through the top coat.
- Cut them out, and fill them with a material.
- Now, if you fill the control joint, you run the risk of that joint cracking through the floor, which will cause damage. This is usually a bigger risk for new facilities that are still settling. If it’s an older facility, then it most likely has settled. But if the customer wants the control joints to remain, your best bet is to install the entire floor, and fill in the joints with a caulk material. The caulk material we usually use is polyurea. Polyurea is nice because it gets hard and rigid. This makes it difficult for fork lifts to damage the joint membrane with stones or nails.
Overall, there are really only 2 things you can do with joints, either fill them in, or saw cut new ones, and infill them with a joint material like polyurea. But regardless of how you decide to deal with them, there are exceptional ways to install them, which can provide better results than others. But as always, you’ll want to listen to the site owner’s needs, so that you can provide the best floor that will accommodate his situation.