Asked on Jan 09, 2014

How Do I Repair Cracked Grout on Shower Walls?

by Shari
Three years ago, I had one of my bathrooms completely gutted and remodeled. I am having problems with some of the grout around the tiles on the shower walls cracking (Primarily the horizontal grout lines). All of the tiles still appear to be well-adhered so I would like to fix this before I have a major problem with water damage or mildew. I'm thinking this is something I can possibly do myself but I'm not sure what steps to take. I have two primary questions:
1. Can I just add more grout to the areas that are cracked, or do I have to remove some (or all) of the cracked grout before re-grouting?
2. How do I know whether to use sanded or unsanded grout?
Is there anything else important I need to know before I attempt this repair?
  19 answers
  • You do need to get most of the old grout out. Unsanded grout is used for glass and stone tiles and sanded grout is usually used for porcelain and ceramic tiles. Is the grout rough? Then it is most likely sanded grout. Make sure the area is dry before regrouting to allow any moisture to evaporate and do not shower for a day or two. There are now tubes of grout since you will not need much if you can match the color. Good luck. Just be careful get old grout out. If you need some pointers go to youtube and put in grout removal. good luck
    • See 1 previous
    • Anna Anna on Jan 11, 2014
      @The Garden Frog with C Renee It is also based on the width of the grout lines
  • Building Moxie Building Moxie on Jan 09, 2014
    First unsanded grout is used most frequently on walls and ideally only when the tile spacing is 1/8" or less. Identifying what you have may be as easy as digging some out - does it feel (extra) gritty when you break it down? then it is probably sanded. From here it looks like it *could* be sanded but I can't really tell. (you could always be prepared for both and do a little test to match). For the repair dig out as much as possible, working very carefully as not to harm tile. For small(ish) repairs use a grout saw ( or other grout removal hand tool. For large repairs, a multi-tool fitted with an appropriate accessory. When re-grouting consider a latex additive for flexibly. In some areas a caulk may actually work just as well. there are sanded caulks available in many popular grout colors. I'll save thoughts on why this might have happened & Hope it helps. Easy repair. Good luck. ~jb
    • See 1 previous
    • Building Moxie Building Moxie on Jan 09, 2014
      @Shari glad I could be helpful and @The Garden Frog with C Renee makes some really good points. you often use unsanded as not to scratch glass or soft stone or glazed ceramic when you are grouting. completely dry absolutely key. I pulled up because of course I do not know all the circumstances. or the installer and really can't see the entire job, but when I see cracking like this of course I think about the substrate. Some cracking in any house (build of wood) would be totally understandable and I mean 3 years and this is the first you are seeing then okay. I just wonder if this isn't the first you'll see. .... and resisting sliding into any more speculation. do your fix, it's all you and still good luck.
  • Shari Shari on Jan 09, 2014
    @Building Moxie I actually had cracking grout probably within the first year but it seems I'm noticing more and more. :( My house is concrete block on a poured cement foundation. My intuition/gut tells me this contractor did not do a great job so even though I have another bathroom I want to remodel, I have not called him back. I've included a few photos of this tub area during the renovation. I know it's hard to assess from pictures alone but if you spot anything out of the ordinary, I would appreciate you pointing it out so I can take the necessary corrective measures.
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    • Building Moxie Building Moxie on Jan 09, 2014
      @Shari these are super pics and it is great that you captured these. I will say that it is good to see the tile backer and the install looks really clean (from what I can see) which does usually point to quality workmanship. I will also say that I'm totally unfamiliar with the specs on backerboard over block (they probably could be easily obtained with a little goggling) ... I followed you maybe you can follow me back and I'll pm the rest.
  • Jeanette S Jeanette S on Jan 09, 2014
    Having removed grout and regrouted, be sure and take your time. Get the old grout out and then wipe down with clorox to discoursge not soak, just wipe down with a cloth dampened in clorox...leave 24 hours before regrouting. MAKE SURE YOU KNOW WHICH SIDE OF A CHISEL TO USE FOR REMOVING GROUT! (A chisel used one side takes the grout out and turned 180 degrees will chip tiles!) Good luck.
  • Monday West Monday West on Jan 09, 2014
    You need to sand out the grout first as it's of no use anymore and won't be fixed further. Then get in touch with some expert on that or you may look for DEA solvents which can be applied as filling in those spaces to give it a better look.
  • I'll tell u that ur contractor should of used an anti-fracture membrane, such as Ditra.
  • Susan Cryor Susan Cryor on Jan 11, 2014
    EXPERIENCED.......take note We had that....I wore down my wrists with hand tool...told hubby can not do it Got special dremmel tool....he went to the task Blade was wrong size Chewed up tiles Tried to remove damaged tiles Pulled Sheetrock out MAJOR mess Called a tile guy to fix our mistakes Learned doing it, when we do not know what we are doing is costly.
    • Katie Pepin Katie Pepin on Jan 11, 2014
      @Susan Cryor , omgoodness..... We were reading and came to your post.... you had us laughing..... not at you, mind you. But, I could so totally see that happening to me. Just the way you posted your comment spoke volumes.... Thanks for the warning and the smile. I think I will leave it to a pro as well....
  • KMS Woodworks KMS Woodworks on Jan 11, 2014
    90 percent or more of all cracked "grout" applications have to do with substrate movement. I have found sanded grout to be a bit more robust than non-sanded...though this is a bit of an apples to oranges comparison. Non sanded grout should never be used in spaces bigger than 1/8" ...sanded grout is a bit too coarse to work into grout spaced smaller than 1/8" a direct comparison is not very practical. cracks are more common in "plane changes" like corners. here i like to use matching color caulk. As is is flexible and can tolerate minor movement. before you go to all of the trouble of digging out the old caulk make sure the wall is secure, press hard against the wall were these cracks are and see if you get any tile movement. if you do get movement, this will need to be fixed first or you will just be repeating your efforts in another year or so.
  • Anna Anna on Jan 11, 2014
    And be sure to use sealing grout when so it does not erode, or hand seal after you are finished
  • Susan Cryor Susan Cryor on Jan 12, 2014
    FYI I have used NuFinish car wax on my tiles for over 30 yrs after properly sealing the grout, the water rolls mold n grout really protected from chemicals learned this from sister when we lived in Florida. Yes, we squeegee down the tile after showering. Sure that helps as well.
  • KMS hit it right on the head. You have substrate movement! You didn't note where the cracks are, but I'm guessing at the base of the window. You should always wrap your wall material (drywall, durock, etc.) around window & door least a 12" or more. The dissimilar material of the windows & doors moves in different directions. When you have a seem right at a corner, this will project through. This is why you also get cracking on the inside corners of shower walls and where the tub/shower pan meets the tile. These areas have to have a flexible sealant applied. Premier Cont. also made a good point about the anti-fracture membrane from Schluter, but got the wrong product. Ditra is used for floor. They have a product called Kerdi that is foe walls & showers and is GREAT! Its' not the easiest to work with (which is why most guys don't use it) but it's the best. This is going to continue to crack. Digging out the grout and re-applying isn't going to stop it. If it isn't going to be taken down and done correctly, the only thing you can do is to add a flexible sealant joint at the crack location. This joint will then have to be monitored and replaced over time.
    • @Houseworks Unlimited, Inc. should look up specs on ditra, it can be applied to walls. Kerdi is for waterproofing only, ditra is anti fracture. Kerdi board could also be used as anti fracture as long as the seams and screws are placed correctly. In summary, this thread is for cracking grout not waterproofing. Ditra is used to prevent movement of substrates
  • Shari Shari on Jan 12, 2014
    @Houseworks Unlimited, Inc. No cracks at the base of the window. Other than one spot of mildew on the bottom left corner of the window by the sill (water collecting on the window sill, I think and I'm going to address that in this repair), the window area appears in surprisingly good shape. On the window wall there are 2 short (less than 1 inch) horizontal cracks but they are closer to the left corner (but not in the corner) and about 10 to 12 inches above the bottom of the window. Most of the grout cracks are on the left (shower head) wall. There is one tile just above the hot/cold/shower diverter handles that has cracks in 3 of the 4 sides. Interestingly, the biggest cracking issues are between the top tile and the bullnose tile border almost the entire length of the left wall and around to the left of the window. (My first picture on this post is of that seam between the top tile and bullnose tile.) I also have some horizontal cracking on the right wall--also between the top tile and bullnose tile. I did check for tile movement on all three walls as @KMS Woodworks suggested but could not detect any. I certainly don't dispute substrate movement but the whole idea completely freaks me out because I live in an area prone to sinkholes. Four years ago, a sinkhole opened up underneath a neighbor's house just a stone's throw from me. We also live only about 5 miles from the sinkhole that opened up and swallowed a Seffner, Florida man last March while he slept in his bed. Sad...and really scary.
    • See 2 previous
    • @Shari You can find some great contractors from professional remodeling associations. NARI has a local chapter in your area ( that you should look into. We've been involved with NARI for almost 20 years and have really found it to be beneficial. Good luck.
  • Janice Janice on Jan 12, 2014
    There is a tool used to remove the grout ask at the home improvement store .Remove the old grout and replace.
  • I believe it is being caused by shrinkage do to moisture and settlement within the walls. Common at times. You simply need to purchase a grout removal tool clean the joints and re grout the whole thing not just the lines cracking. if not you will have a color difference between the grouts. You do not have to clean out all the joints, just the ones cracking, Then simply re grout, The new grout will adhere to the other joints as well, enough to make the colors match. Then after grouting wait the half -hour time period and wipe down with clean cold water and a grout sponge to remove the access. Sanded grout is for floors or larger then 1/8 inch tile joints on wall tile. for these joints I still would go with a non sanded grout. You can also purchase an additive to mix with the grout to strengthen its bond to the tile, this will help minimize any future cracking. Good Luck
  • CeramicTilePro LLC CeramicTilePro LLC on Jan 20, 2014
    1.Those cracks are a sign of movement. Grout is not flexible so any movement, whether it's minor such as expansion/contraction from temperature changes or more major issues that are structural, will result with cracks. You can perform a simple task by knocking on the tiles with your knuckles and listen for any "rattling" sound. This would indicate a "loose tile" and re-grouting will not fix this issue. The tiles would need to be removed carefully and re-installed with thinset mortar then grouted. If the tile sounds solid, you could scrape the old grout out and use epoxy grout which is amazing! I made a video on how to use the epoxy grout on my Youtube Channel. 2. What type of grout should be used? Personally, I would use epoxy grout. I like the "100% Solids Epoxy" by Custom Building Products because you can use ANY sanded grout color to match your existing grout. As far as cement grout, a rule of thumb is to use un-sanded grout for joints up to 1/8" and sanded for everything else. Please keep in mind that some materials such as marble and glass can scratch using sanded grout so please do your homework and check to see what the manufacturer recommends.
  • I have a video on my website on How to fix cracked grout check it out you can match the color of your exists in grout with my color sealer and by adding it to grout with a little water you can fix that problem in minutes. Any questions you can call my office and speak with me at 1-800-631-0716. Michael
  • The Redesign Habit The Redesign Habit on Jan 04, 2016
    You can also use a small grinder attachment on a Dremel if you have one and it makes removing the damaged grout really easy. I did this on a whole kitchen floor and it made the process go quite quickly and then you have a nice cleaned up surface ready to re-grout.
  • FRED RIGGS FRED RIGGS on Nov 06, 2016
    get a grout removal tool. Not very expensive or a dremel tool to remove grout. Be very careful, take your time and remove all the bad/broken grout. Vacuum everything out. Keep it dry and then replace the grout. Dremel makes a grout removal bit. I own one myself.
  • Tmr Tmr on Mar 18, 2018

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