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Prevent aged, cracking caulk around your tub by using grout the next time you seal around the bathtub.


Photos by Joe Provey, Home & Garden Editorial Services

The joint between a bathtub and the wall needs to be carefully sealed to prevent water from leaking behind the wall and perhaps through the floor into the room below. A common approach is to fill the joint with caulk, sometimes labeled "kitchen and bath" caulk. Unfortunately, caulk is difficult apply neatly and usually ends up looking messy. It also tends to peel slightly at the edges creating perfect pockets for mildew and bacteria. That's the black stuff you see. Scrubbing with bleach or high-powered detergents can render the caulk clean, but it's a nasty job-and there is a better way to avoid so many deep cleanings.

Seal the tub to wall joint with grout. It's cheap, long-lasting, looks great, and is better at resisting discoloration due to mildew.
Use tile grout. I used the Polyblend brand. It comes as in powder form, although you can buy tile grout premixed as well. There are two types, sanded and non-sanded. For this fix I'd recommend non-sanded, although either will work.

Follow the steps below for a perfect seal.


1. Clean out the joint with a razor scraper. You will often be able to pull out long segments of caulk once removal gets started. For an old grouted joint, an old chisel may be helpful as well. Don't bother with chemical applications that soften caulk for easier removal. This is just another gimmick to part you from your hard-earned dollars. In most cases, caulk is easy to remove.



2. Wipe away debris. You can use an old toothbrush to help sweep away loose particles. Then sponge clean with vinegar to kill off any remaining traces of mildew. Finally rinse and allow to dry.



3. Mix grout powder with water in a disposable bowl until you have a stiff paste. Go slowly at first: It's easy to put in too much water, in which case you'll need to add more grout. Add only small amounts of water until the desired consistency is reached. Stir the grout for five minutes. Then set it aside and fill the tub with water. The weight of the water will open the joint between the tub and the wall a bit more than it already is.



4. Allow the grout to sit in bowl for 10 minutes. Then stir again and begin to fill the joint. My preferred tool for this operation is a wooden craft stick (a.k.a. popsicle stick or tongue depressor). Use it to press the grout into the joint, and then to scrape off excess grout. Use a gloved finger to give the joint its final shape. The key is that you have the vinyl glove on; and run your finger gently against the grout for a smooth finish. While you're at it, remove old loose grout from between tiles and fill with new grout.



5. Allow the grout to set for about 20 minutes. Then lightly wipe away excess grout with a damp sponge. Use a sponge with a fine texture to avoid pulling grout from between the joints. If the grout dries before you clean it off, you're in trouble. It's tough to remove once it sets. So be sure to wipe the tile clean at the appropriate time. You may now drain the tub.



6. Wait two hours for the joint to harden and remove any remaining grout residue (haze) from surrounding tiles and tub by buffing with cheesecloth. Wait overnight for the grout to become completely dry before using the tub or shower.



  • Don

    Won't the grout seal between the tub and wall eventually crack?

    Reply
  • don

    yep !


  • mcgowann

    I've tried both and the caulking lasted longer than the grout. Also, the grout mildewed faster than the grout did.


  • Leen

    Can you use grout around a kitchen sink that has formica counters around it?

    Reply
  • Annika

    Sealing the grout with a good grout sealer is an essential element of tiling. I didn't see that step anywhere...

    Reply
  • Robert

    I hate cauling as much as anybody, but I don't like this idea at all, espeacially around a tub. Grout cracks, and is not waterproof.

    Suck it up and do it right!

    Reply
  • 64c0dc00

    Wish they would come up with something better than grout & Caulk,I REALLY hate because it gets dirty so fast and it seems that every thing sticks to it (dust as well as dirt & grime). Because caulk remains soft things just stick to it and grout it just cracks after a while. PLEASE think up something new and improved!!

    Reply
  • LongTimeContractor

    I couldn't believe me eyes when I read the title of this article. Being a contractor for over 30 years I can tell you he's WAY off base here. When I tile a bathtub, I purposely don't put grout in ANY of the joints of adjoining surfaces, including the verticle corner joints. The reason is they crack! I always use a pure silicon type caulk and no, it just doesn't last a lifetime, few things in life do. We ask a lot of this sealed area and it's important to keep it in good working order. Preparing is the hardest thing (I like to use steel wool to remove the last bits of silicon) and if you use a row of tape on each side of each joint, it will look super professional when you're done! Forget grout!

    Reply
  • nat

    i obviously know nothing about construction so i trusted the internet and condo association with 'good contractors'. The entire tub is now grouted and you are all scaring me. It looks good, but these joints are exposed to water daily. When I see discolorations during moisture or tiny crevices, I want to hang myself at times for fear there will be leaks into lower units. So much was invested this year in work to avoid this kind of problem. Then the contractor who did the floor used grout by the entrance and it crumbled right away. He came back and said grout in that area will always crumble, then asked if i had more grout anyway. I said I didn't, so he put an application of tan caulk over the threshhold that looks crazy. They said when I get a new carpet outside bathroom, it will just extend over the whole thing. The trims around the new floor is crooked and there were gaps between the vanity and under the trim where all kinds of crawling insects have a convenient walkway. Also their brand new windows leaked during recent storms. They are not getting back to me over this. Anyway, the bathroom I am trying to spackle some messy caulk over the trim in some areas, which seems to look a little better. Nephew told me to do that but he's across country. I am also trying to caulk under the trim that has gaps, but after reading this article, maybe white grout would be okay. btw trim was painted all white for some reason. This is around the floor and not where water would be exposed a great deal. However one of the contractors insinuating the grout is not a good defense against water overall is very concerning. Why was this suggestion ever made in an article? What kind of supergrout is being used that won't crack?

    Reply
  • K&G Property Maintenance

    Sounds like you have a contractor problem. I would address that issue first. As far as the caulking is concerened - in 22 years I have never seen a grout product that is waterproof. Silicon is the best answer to prevent leaking and mold. Most caulking products have microban in the product which is an antimicroibial mold deterant. Spend a few bucks on the product - the result will be a longer lasting seal. Another issue regarging grout. it is very difficult to remove and you can end up damaging the porcelan tub or toilet where it has been applied. Lastly - caulk is fexiible and will keep a water tight seal longer.


  • Property Maintenance

    As far as the caulking is concerened - in 22 years I have never seen a grout product that is waterproof - it is used on tile floors and walls in bathrooms - but needs to be sealed properly ( I have found most contractors don't bother with this important step). Silicon is the best answer to prevent leaking and mold. Most caulking products have microban in the product which is an antimicroibial mold deterant. Spend a few bucks on the product - the result will be a longer lasting seal. Another issue regarging grout. it is very difficult to remove and you can end up damaging the porcelan tub or toilet where it has been applied. Lastly - caulk is fexiible and will keep a water tight seal longer.

    Reply
  • 11 Comments / 1 Pages
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