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Tile Grout Sealing / Caulking

Caulking and Sealing Tile Grout Tips

When installing new ceramic tile, absolutely make sure that the horizontal seam between the bottom row of tile and the tub and/or shower is not grouted! This seam must be caulked with the best quality 100 percent silicone caulk you can buy. These caulks are available in various colors, should you be using a colored grout. Grout will shrink after installation and a very tiny crack will exist, trust me.

The best way to caulk this crack, believe it or not, is to do it in your bathing or birthday suit. Why, might you ask? The reason is simple. The tub should be filled up to the overflow with water when caulking this joint. The added weight of 30 to 50 gallons of water plus your body weight can cause the floor below the tub to deflect. Leave the water in the tub as long as possible to allow the caulk to cure. Don't leave water in the tub like this, however, if you have small children at home! Left unattended, they may think the tub is a swimming pool. Drownings have been known to occur.

AUTHOR UPDATE - April 2015: The following material not in red color was written before I had extensive experience with homeowners who had SEALED their grout and then had the grout get stained by a liquid that had seeped UNDER the sealant. That can happen along the line where the grout touches the tile.

In these cases, the homeowners discovered it's nearly impossible to remove the stain because all cleaners are REPELLED by the sealer.

Now I suggest to people to NOT SEAL grout. If you use Stain Solver, a Certified organic oxygen bleach, it will remove any stain from grout in minutes. 


After the grout is dry (three to five days), seal the grout with a silicone grout sealer. These products are available at your tile supplier. Be careful not to get these products on the tub or shower floor, as they are very slippery. The grout needs to be sealed, as it can and will absorb water. Remember, grout is nothing more than fine cement. The sealers also help to keep the tile grout clean. Reseal the grout every six months, after thoroughly cleaning the grout.

Existing Construction

Do all of the above, however, clean, clean, clean before caulking or sealing. These caulking and sealing products will not stick to soap scum very well!

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18 Responses to Tile Grout Sealing / Caulking

  1. I regrouted my mom's tub with a sanded silicone. Does this still need to be sealed? Also I'm redoing a few tiles in the window that were crooked. Should I use regualr silicone for this? I am a total amature , but we can't afford a tile guy. HELP!

  2. I have used your Stain Solver to clean the grout in my kitchen. What can I use to Seal the tile and grout?

    • I do NOT recommend sealing grout after cleaning it. The sealers can make it HARD to clean the grout if a liquid like red wine or grease seeps UNDER the sealer. That can happen along the edges of the grout/tile interface. Just keep Stain Solver on hand and clean the grout once a month. Don't let it get away from you and it will be EASY.

        • What is the best steam cleaner to clean grout after applying Stain Solver. I have been mixing Stain Solver with water and getting on my knees to clean the grout. I need a light weight Steam Cleaner so that I do not have to keep bending.

  3. I just re-grouted my shower with non-sanded grout (small joints). I will let the grout cure for two or three days before applying a silicone based sealer. Should I caulk the horizontal floor joint (where the tile meets the shower floor) before or after I apply the sealer?

  4. Hey Tim,
    You are 100% right when you say that sealing is a must in these situations. Unfortunately, people do not have understanding for that every time. I also agree that silicone grout sealing is the best for the bathroom. Great post!

    • I'm updating this post now. I've changed my stance on grout sealing. Most of them block cleaning solutions in case a stain seeps into grout along the grout / tile interface.

  5. I have a recently built home. The colored caulk in the master shower where the floor meets tile has been getting moldy. I use a daily spray cleaner but it does not seem to help. Any suggestions?

  6. Tim, we just tiled our very small bathroom...ready to seal the grout. We have tile only on the floor, it's off the bedroom, you say don't seal the grout, but I'm wondering about the wet feet from the shower,not that we won't be using a bath mat,wouldn't it give a little extra protection to the floor if you seal the grout? Just wondering before we go ahead with this, yes or no to grout.

    • I think you're making a HUGE mistake not using a bath mat. Someone's going to fall. Read the RED type above again.

      Small amounts of water on a tile floor do not pass through the grout and cause the subfloor to rot if it's wood.

  7. Thank you for this helpful post, Tim. Would you also recommend making sure that there is no grout at the seam where tile meets a window sill, and just caulking with a 100% silicone caulk? I have been curious about this as when I went to recaulk my tub, I noticed that the builder grouted the area where tile meets the tub and then caulked over the grout, and also just grouted where the tile meets the window sill in both kitchen and bathroom, and now the grout is failing. It seems like using caulk in these areas would make more sense since two different materials meet, and caulk more give you some flex.

  8. We completely redid our bathroom this summer with a fiberglass tub and tiled shower walls. Today we noticed some sandy grit (assuming it is grout) seeping out from underneath the silicone where the back of the tub meets the tile line. I belive there is grout on the tub line, behind the silicone seal: should we scrap it all out then seal it back up with silicone/caulking?

  9. This makes sense to me, but I have found other information that says the exact opposite -- that the joint between tub and tile should be GROUTED, not caulked. Here's one in particular:


    It says: "Caulking this connection is fine if the wall is some sort of one piece sheet or enclosure, but with tile it should not be there. The grout joints are designed to prevent water from penetrating the wall but any small amount that does penetrate is able to evaporate out and/or weep out along the bottom. If the tub/tile connection is caulked the water cannot wick out through the bottom grout joint and moisture builds up and is able to feed the mold that eventually develops."

    Is this true? My tub-to-tile is grouted, and has cracked, and I've been researching what to do about it -- and I still don't know! Caulk or grout? Any help?

  10. I find this a bit confusing because the red seems to contradict the first part so are you saying that you should seal the grout along the tub edge, or do not seal the grout along the tub edge? Mine is cracking now,and is about 5years old. Will regular silicone caulk work?

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