5 Tips to Help With Concrete Joint Sealing

Posted on: 4 June 2017

If you want a smooth look between concrete slabs, you may want to seal the joints. In order for this process to be as effective as possible, you need to prepare carefully. Here are some tips to help you  

1. Wait Until the Concrete Is Set and Cured

You can't seal the joints between the slabs until the concrete is fully set and cured. This doesn't just mean that the concrete is dry and ready to walk on. Rather, it means that the concrete has gone through the shrinkage and expansion process associated with water gain and loss that happens as the season's change.

On average, the drying shrinkage of concrete is about 4.23 mm for every 3 metres length of the slab. If you put in the joint sealer before that shrinkage has occurred, the concrete will shrink, and then, gaps will appear between the sealer and your slabs.

2. Choose Your Sealer Carefully

There is more than one type of concrete joint sealing material on the market, and you should look at the expansion capabilities of the sealer before choosing one. If you live in an area where the temperatures routinely fluctuate, your concrete will be more prone to expansion and contraction, and you need a sealer that can handle that.

Note that you may see both concrete joint sealers and fillers at the shop. Fillers tend to be less elastic than sealers.

3. Clean the Joint

In order for the sealer to adhere to the concrete, the joint needs to be clean and free of debris. Before putting in the joint sealer, take some time to clean out the debris. You can brush out solid debris or even vacuum it.

If you use a pressure washer to clean the joints, you need to wait for the area to dry fully before you move onto applying the sealer.

4. Use a Back Rod

Finally, before adding the sealer, you may want to put a back rod into the joint. A back rod is similar to a piece of rebar, but it doesn't have the corrugated edges. Backers tend to be smooth and cylindrical in shape.

They give the sealer something to cling to, and that makes the seal more secure. They also help to waterproof the seal so that water doesn't seep into the joint and under the concrete slab.  

5. Consider Hiring a Professional

If you want the job to be perfect, you may want to hire a professional. They can seal your concrete, repair cracks and much more.