grout repair question

Discussion in 'Shower & Bathtub Forum & Blog' started by nothingeverworks, Oct 20, 2009.

  1. nothingeverworks

    nothingeverworks Member

    Messages:
    42
    Location:
    Florida
    I'm repairing some of the grout on the tiles around my tub that has come lose or has been pushed into the wall. The problem is only in the corners.

    There seems to be a lot of space in the corner where the tiles meet that needs to be refilled with grout. I'm talking about the space behind the tiles -- it's a good half inch. It would require a lot of grout and really, I doubt i could fill it up completely. I also think that this is what caused the grout problem to begin with (i.e. a lack of support behind the grout in the corner)

    should I be filling the gap with something before grouting? expanding foam perhaps?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    First, industry standards for tiled structures call for the use of caulk at all changes of plane (corners) or material (say tub to tiled wall). So, you shouldn't grout it anyway. If the tile are coming loose, you have other problems, since mortar rarely works that way...it would be bonded to the tile and you'd end up having the tile break or a big chunk come out of the wall.

    But, if you want to do anything in the corners, they make foam backer rod that is designed specifically to be pushed into a crack, then have caulk applied on top. You choose the diameter of the foam rod based on the width of the crack. It comes in both closed cell and open cell foam. You get it bigger than the crack, push it in, then caulk over it.
  3. nothingeverworks

    nothingeverworks Member

    Messages:
    42
    Location:
    Florida
    It's too bad the installer didn't follow the industry standards. Of course that's never happened before.

    So how should I proceed? Should I remove the rest of the grout in the corner or should I fill the space and caulk over it all. I just got the tub refinished so I'm s little hesitant to remove the remaining grout and have falling grout chip the new finish. But if that is the only way...

    Are the foam backers available at big box stores or do i have to go to a specialty plumbing store?

    Thanks for the reply jadnashua.



  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    I did a quick search on HD and Lowes, and did not see it on line, so I'd have to say no, they don't carry it. Try an independent lumber yard, or buy it on-line.

    If you put a blanket or something like that in the tub, you should be able to clean the grout out. Depending on the structure, you can sometimes get away wtih grout, but it doesn't take much to cause it to crack. The foam backer rod, if you choose the closed cell foam would also help keep water from penetrating if you had a problem with the caulk. You could try regrouting, but matching color is tough, and with a gap that large, you'd need sanded grout, if what you have is unsanded because most of the joints are narrow, it would look different. Unsanded grout shouldn't be used in anything wider than 1/8" - or, it will crack.
    Last edited: Oct 21, 2009
  5. nothingeverworks

    nothingeverworks Member

    Messages:
    42
    Location:
    Florida
    thanks for checking. I will check the specialty stores. i'm sure i will find it somewhere.

    thanks again.

    j.


  6. nothingeverworks

    nothingeverworks Member

    Messages:
    42
    Location:
    Florida
    turns out the big box stores do carry it. it's in the insulation area.

    i'm thinking i should regrout the corners so it better matches the existing grout color. the caulking is way too white and it looks odd with the no so brilliant white grout. but i will caulk along the tub edge.

    i can't tell whether the existing grout is sanded or unsanded. What is typically usually used with 6" x 6" ceramic wall tiles?

    thanks again.

    j.[/QUOTE]
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    You should use sanded if the grout joint is greater than 1/8" and unsanded for 1/8" and less. It's usually fairly easy to tell the difference, unsanded just looks a lot smoother. It is possible to use sanded in smaller joints, but it takes more work...the unsanded is creamier and is easier to get into smaller joints. Also, if you try to use unsanded on larger grout joints, it not only is less strong, but it tends to shrink when it cures and results in cracks.

    There are specialty companies that make matching caulk colors to almost any grout. Depending on what you have, you may find it at Lowes, or a local tilestore. But, you'd need to know the brand and color of what's there.
  8. nothingeverworks

    nothingeverworks Member

    Messages:
    42
    Location:
    Florida
    I found some caulk by Mapei which matched the grout perfectly. Used the backer rod -- worked like a charm. Got it all done. Looks great.

    Thanks again for the help.

    J.



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