Sealing concrete is the need of the hour. Because concrete is highly porous and can welcome moisture and chemicals inside, it needs extra care and protection. Basically, a concrete sealer forms a protective layer on the surface of the concrete area to keep all sorts of harmful substances out.

Now, the process of concrete sealing seems pretty simple but if you do it wrong, it could lead to formation of bubbles and blisters on the surface. The main aspect you need to keep in mind is the weather conditions when you’re applying a concrete sealer - too high or too low temperatures affect the evaporation process. Also, you should know what to avoid and be completely well thorough with the process in order to avoid the bubbles and blisters.

Concrete sealers that are not 100% solid use evaporation technology to cure. It is the water part of the sealer that helps make application of the concrete sealer possible. After you apply the sealer, the water evaporates leaving behind a plastic layer to form on the concrete surface. Once the evaporation process is done, the plastic gets hard. The air and gases need to escape during this time and hence, if the sealer dries too quickly or too slowly, it can trap the gases and moisture outside.

When the temperature is cold, the sealer dries too slowly, if it’s too low, it dries fast and if the climate is windy, the top dries before the bottom. Thus, there is a lot of care to be taken when applying the sealer. Firstly, concrete sealers should never be applied when there is moisture on the surface. Freshly poured concrete is never sealed for the same reason that it has moisture which needs to evaporate. Secondly, thick coats of sealers don’t let the gases break out and bubbles are formed inside – the top dries while the bottom sits and wait, forming blisters and bubbles.

Removing Sealer Bubbles and Blisters

So, the blisters and bubbles have showed up – you can’t leave it like that. You need to fix the concrete surface by taking care of these sealer bubbles and blisters. Getting rid of the blisters and bubbles in the concrete could be as easy as reapplying the concrete sealer or as tough as stripping it all and resealing it. How you should go about it depends on the type of sealer you have used and how deep the blisters and bubbles are.

All in all, there are three common remedies for different sealers and different situations. For a solvent based sealer, the defects can be removed by giving the affected area a solvent bath with acetone or xylene. If it was water-based sealer, try the solvent on a sample before giving it a bath or you can also remove the simple surface bubbles and blisters by giving another coating of the sealer. But the tough part comes when the bubbles are deep. Then you need to strip the sealer, clean the area and reapply the sealer.

In case you are having troubles figuring out the best alternative for your surface, the best thing to do would be calling up the manufacturer of the concrete sealer and asking the technician.