Asked on Nov 02, 2012

Is flexible grout worthwhile?

Melissa G
by Melissa G
We have thin cracks in the grout in our shower. Two people have given us estimates -- one would use a flexible epoxy grout to allow for some movement of the floor tiles, and one would use a standard hard grout. The second estimate is a lot cheaper, and the man said flexible grout isn't necessary. So can anyone tell me whether he's right? Is flexible grout worth the money?
  13 answers
  • 3po3 3po3 on Nov 02, 2012
    The epoxy grout should last forever. If you consider the potential cost of a repeat grout job and the cost of repairing a potential leak, it may be well worth the extra cost. And if you don't believe me, here is a second opinion:
    What type of grout should I use for marble flooring my master bathroom? Normal, or epoxy?
  • Douglas Hunt Douglas Hunt on Nov 03, 2012
    I happen to be looking for tile for a shower right now and I've been convinced epoxy is the way to go as well.
  • FloorNerd FloorNerd on Nov 03, 2012
    99% of grout cracks are caused by movement in the subfloor so flexible grout would be the your only option as appose too taking it all up and beefing up your subfloor unless you support it from underneath by sistering or x bracing the joists.
  • FloorNerd FloorNerd on Nov 03, 2012
    grout lines also need to be the right size depending on size of the tile and whether to use sanded or unsanded grout.. maybe they didn't use the correct grout or grout line spacing
  • Melissa, if you are not experiencing any water leaks, then the flexible grout is the best solution for you at this time. The vendor should scrape out the present grout before installing the flexible grout so there is a good bond.
  • KMS Woodworks KMS Woodworks on Nov 03, 2012
    @ has the root cause... substrate flex. where this is most common is in a corner where one plane meets another. I prefer to caulk these areas. Each plane in its own right is pretty stable but the transition from wall to floor or wall to wall can move. for these I use a caulk in the same color as the grout, custom building products even has sanded caulk that matches in both texture and color. If your cracks are only found in corners this would be the route to go.
  • Mike Potter and KMS said it all. Sounds as though the sub floor under the shower pan is faulty and even using flexible type of grout it will still crack over time. as as Kevin said, corners unless really done right work best if they are caulked. Most grout companies make caulk that matches their grout products. My bigger concern however is not the flex but the install. Grout is very porous. It can easily leak down to the sub floor if given enough time. If the floor assuming it is a mud pan which it should be if your placing tile on the floor. Should have been done in such a way that there should be no movement at all. The shear thickness and materials used makes for pretty much a two or three inch or in most cases even thicker cement slab of sorts. And along with that a rubber or lead pan is installed and connected using a special drain fitting that allows any moisture that possibly could collect under the tile a way out to the drain system. But hearing that you have cracks makes me think that the mud floor was not done properly or the mix of sand and Portland type II cement was wrong and the mud pan is failing. IN any case be sure once your fix the cracks that you seal the floor and lower area at least of the shower area to help prevent moisture from getting under the floor system. Lastly, be sure that you remove ALL of the grout that is already in the spaces between the tiles, and clean the floor really well to remove any soap scum to assure that the new grout will be placed properly and last. But personally I think you have something else going on that needs looking into.
  • Melissa G Melissa G on Nov 03, 2012
    Thanks, everyone. This is very helpful. Woodbridge, we did actually get a third estimate that we discounted because the man said right away, over the phone, that the whole thing needed to be redone. We thought he was being extreme, but it seems he could actually be right. So should we get a few more estimates to figure out if we need to redo the whole thing?
  • Melissa G Melissa G on Nov 03, 2012
    I should mention that a big reason we're addressing these cracks is because we had tiny Argentine ants coming through the cracks into our bathroom earlier this year. Our exterminator said the cracks allowed water to get down into the mud pan, which they like, and allowed them to come right up through the cracks. The shower is on the second floor and we have not noticed a leak in the ceiling below.
  • Ants coming in though between the floor and the wall indicates that something is wrong. If they are coming in from floor and wall area in the main bath room as opposed to the shower, then you need to find the source of the ants and deal with that, then caulk the floor where it meets the wall to keep any other insects out. But I think your on the right tract, getting another visual opinion on the job, as unless the grout was done wrong, being mixed to thin, or as Mark pointed out the wrong grout used for the width of the grout line itself, something else is going on and you do not want to put more good money into something that will only need to be fixed again in a few short months.
  • KMS Woodworks KMS Woodworks on Nov 04, 2012
    ants all the way to the second floor is a pretty big deal...I have seen them invade some home on ground level coming in through foundation cracks etc. Though I have not seen them up on second floors...In addition to a grout or tile person I would bring in an exterminator to track this back to its source. You need to treat the cause...not the symptoms.
  • Last thought on this, Ants are drawn towards damp areas. This indicates that there is something going on in the form of leaks under the tile that do need to be addressed. They are just one more indication that this is a bigger job then just replacing the cracked grout in the shower.
  • Melissa G Melissa G on Nov 07, 2012
    OK, thanks. That is helpful.