To begin with, you can’t just add new grout to old grout. If water or grit is allowed to seep between the joints of the tile that the grout seals, it can cause serious issues in addition to being unsightly.

When trying to repair or completely regrout a wall, floor, or other surface, you don’t necessarily have to remove all of the existing grout, but there are a few important things to keep in mind. Before you start puttingtering with putty knives, grout mixtures, or caulking and getting serious about regrouting a dark area, be ready.

You Can’t Just Add New Grout to Old Grout

1. If you try to add new grout over your old grout, the new mixture will not properly adhere to the existing grout or tile edges, leaving your shower vulnerable to water damage. Grout will simply cure and start to break away if you try to fill in cracks or areas of separation with it directly; this will put you right back where you were before.
2. Furthermore, since the new layer would be thin, adding more grout would not be aesthetically pleasing. This means that your old grout will be seen beneath, and if you were to only treat one area, you would see the difference in the “repaired” area versus the area that you did not add grout to.

Advantages of Grout over Grout

Because the old grout does not need to be removed, applying new grout over old grout is less difficult than a complete re-grout. Additionally, it can fortify the surface to improve water resistance and make it more impervious to contaminants. However, you must make sure that the grout you use to re-grout is the same one you used the first time. If not, the second layer won’t stick well to the first and you’ll have to repeat the process in a couple of months.

Prep Work for Regrouting

It’s not a good idea to add new grout on top of old grout. In order for water and other potentially harmful substances to not erode the material supporting the tiles and grout, the grout must combine and harden.

Not all of the grout on the surface needs to be meticulously removed. To give the new grout a good chance of sticking to the old grout, the soiled or crumbling grout must be chipped or wiped away. New grout won’t stick very well to old, grimy grout, according to The Grout Medic.

Make sure to check for any issues that might have led to the grout crumbling or appearing particularly soiled or moldy. Prior to starting the work of installing the new layer of grout, address issues that the old grout encountered.

Suggested reading: What color grout to use with gray tile? Overall, some colored grout contrasts with gray tiles: light gray, off white, taupe, brown, charcoal gray, cream, dark gray,  and gray porcelain. 

Steps for Regrouting

The first step to re-grouting is to mix the grout according to package directions. Then use a grout float to spread it evenly across the surface. The grout should be forced into the joints by using the float as a squeegee.

Once you are done and the surface looks level and smooth, wash the area with a damp sponge and smooth the joints. Once the surface is smooth, wash it once more, buff it with a clean towel, and then wait a week before cleaning it again. You can use sealants after allowing it to rest for this time.

Even though re-grouting over old grout can sometimes be more practical, it is always a good idea to call in a trained professional unless you are absolutely confident in your abilities. Now that that is established, here’s hoping your project yields the results you want and leaves your house looking lovely.

Suggested article: Can You Tile Over Tile?

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