Filling Grout Lines with More Grout

by Roger

When there is a significant amount of movement on the substrate of a tiled floor or wall it may lead to grout cracking. When this happens it will leave what looks like a crack in the grout where it has come away from the tile. Unless your grout was installed very recently this is always due to movement in the tile. If your grout is new it may be caused by incorrectly mixed grout. With grout that has been doing this for a while it may lead to whole chunks of grout coming loose and leaving large voids in your grout lines.

While it may be tempting to simply mix up some more grout and fill these voids you need to know that it will not last. If you do this it will fill the grout lines just like new but over time will lead to the same problem. Grout over grout is not a permanent solution.

Why it won’t last

The first reason is that when you go over the top of grout that is already cured with new grout, there is no adhesion to the old grout. It will instead simply create a layer of grout on top of the old grout. These layers have no way of  sticking to each other. When you grout tile the grout actually sticks to the sides of the tile rather than whatever substrate is beneath it. While it will stick to the substrate at the bottom of the grout lines to an extent, it is not a permanent bond. Attempting to grout over the top of old grout is simply stacking two seperate layers of grout. It will always remain two seperate layers.

The second reason is no matter how much of the old grout you may take out to install new, if you do not fix the actual reason the grout failed in the first place, eventually the same thing will happen again. As with any problem you may encounter with a tile installation, you must figure out the initial cause and fix it to prevent repeated problems. This is an involved process which I will cover in a different article. For now I’ll stick with the solution for the grout problem.

What to do

Rather than simply filling the grout line where the grout is missing, you must remove the old grout at least 2/3 the depth of the tile so the new grout has a feasible surface to grab onto. The easiest way to do this is with a grout saw. Ideally you would remove the old grout all the way to the substrate before regrouting it, but 2/3 will be sufficient if it is difficult to remove.

You need to remove any of the old grout that seems loose or has come loose from the sides of the tile. You also need to make sure the spot where the new grout butts against the old is a 90 degree angle, or close to it. In other words from the top of the grout line straight down. You do not want a slope. Eventually a slope must be feathered to a very thin edge. That will be the first place it will fail again, any very thin layer. A 90 degree angle prevents that.

It is also better to make the transition from old grout to new in the middle of a grout line rather than at one of the corners of the tile. The grout line at the corner of the tile has six different spots it can fail, the middle of a grout line has only one. It lessens the chance of failure.

After you remove the sufficient amount of the old grout just mix some new grout and fill the lines. You must make sure you force the new grout into the grout lines very well. You want to make certain there are no voids and the lines are full.

The above method will work to temporarily fix your cracking grout. As I pointed out above, you must find the initial reason for the grout failure before a permanent fix will last. It’s difficult to say how long this fix will work, it may be two weeks, it may last a year. That depends on the severity of the problem that caused it. It also depends on the application (wall or floor) and how much use it gets. A floor in your main entryway will not last as long as a shower that is never used.

You should also take into consideration the age of the grout. If you are repairing grout that has been installed for five years, the new grout, even if it is the same brand and color, will not likely match perfectly. The best solution, of course, would be to fix the cause of the cracking and regrout the entire floor. Depending on what you’re fixing and why this method may solve your problem.

Previous post:

Next post:

Molly

I just moved into a house and it snaps, crackles and pops in every room. It is from the 70′s. The bathroom is the real irritant. It has a heated floor mat by Sun Touch, which they installed with thin set (I think) then laid 12″ tiles over that. It is not level, I can see the wiring/mat between the tiles where caulk has fallen out. I worry about water getting under the tiles, since this is the bathroom.
I suspect you will tell me I have to take it all out, which will damage the heating element, most likely. I’m a senior woman and not sure how to remove the tiles, let alone the heating element in thin set.
Shall I just take a hammer to it? After, that is, finding where to pull the wire from the electricity, which isn’t on it’s own breaker so I can’t just turn it off.

Then, ‘if’ I manage to do all of that, how do I proceed? Is there a bathroom flooring better for old uneven houses, than tile? I’m not the handiest woman, but I also have no money. :oops:

Reply

Roger

Hi Molly,

Yes, it should be removed. The heating element is likely wired into the junction box behind the light switches and it may require an electrician to remove it (per code in your area). A hammer and pry bar will likely be your best option.

Sorry, I know that isn’t what you wanted to hear. I would get someone to unhook your heating element from the electricity then hire a couple of local kids to remove the tile and everything for you. Tile can be installed nearly anywhere, but it needs to be properly installed for a given structure.

Reply

Helen

Hi Roger,
Glad I found your website and have read posts on re-grouting. I bought a 1960′s house four years ago; the former owner had gray slate tile installed over the concrete front porch and it looks nice except it is a little slippery when it rains. My problem: Last year, two or three of the outer-edge tile were accidently kicked loose and now I am noticing the grout between most of the other tile appears to be shrinking and beginning to recede! The previous owner had left a roller bottle of sealant w/no instructions, so nothing has been done … My question: Since the old grout is well below the top edges of the tile, may I simply add a new layer of grout over the old IF there is enough bonding area with the tile? If so, then do I also need to seal the new layer of grout? Annually, or? What is a reasonable labor price? Porch is approx 5 x 14. Thanks! –Senior-citizen Helen

Reply

Roger

Hi Helen,

If there is 2/3 of the depth of the tile exposed then you can grout over it. If not it needs to be taken down at least that far. The tile should not shrink, it is a cement product. It may have been incorrectly mixed or installed wrong. You will not have to regrout every year, grout is permanent. Labor price varies wildly, call three or four contractors and you should see the average.

Reply

Drew

Shower wall grout, angles and movement.
Plus floor tile.

To start with I live in an old house. 1917 old.
Also for both the shower and the floor the workers took everything down to the studs so they could start from scratch. No blaming someone else’s work because they had to build on it.

After they were done installing the shower and redoing some of the tile floor I pointed out somethings but they just brush them off which is driving me crazy. Especially after reading your instructions on how to install backer board and grouting.

-I point out that the bottom portions walls, starting 2 or 3 feet from the floor, bow/slant in towards the center of the shower.
-They say “Its due to the shower pan/material that runs up behind the wall which is pushing it out. Don’t worry about it, everyone does it that way.”

-Really? My neighbors doesn’t.

-I point out that the shower floor is so flat that the water from the shower only meanders slowly towards the drain. I’ll grant this isn’t a huge issue for me, it just seems wrong in that it would be a no brainier when putting in a shower to ensure the floor slants in towards the drain at a reasonable angle.
No standing water occurs.
-They say “it doesn’t matter, any water that seeps though the grout will be caught by the shower roll out pvc shower pan liner.”

(I think of the shower pan as a back up safty device but I what do I know)?
It is? or is it constantly utilized to catch water that seeps through the grout and cracks?

-I point out that the grout around the interior edges of the shower is coming out in chunks only weeks after they finished. I can stick a screwed driver in it, I can dig is out with a tooth pick, I can dig it out with my fingers, I can dig it out by spraying water or washing water over it. It is as if they used a combination of rubber cement and sand for grout.
They come and “fix it” by caulking in and over the gaping grout gaps. No digging things out.

-When they come back again to redo things, should everything be dug out 2/3s of the way down or should the few solid grout areas areas be left alone?
-”They say leave the hard areas and just get out the loose stuff. Then caulk.”

-Should any replacement grout be put in before caulking?

-I point out that I can push on the very bottom of the shower wall and it bends backwards, opening up and extending the existing cracks in the grout MUCH more so.

-They say, “Don’t worry about that. The pvc shower pan will catch all of that. Plus it isn’t out fault, it is because the studs are 16 inches apart. Don’t worry about it. When would you ever push on the wall down there anyways?”

I say it should have been reenforced to prevent this from happening. Do you do this kind of work in other houses? How do you think a customer would react if you told them from the outset that the shower walls would bend? Shouldn’t you have added extra studs?
(how far apart should studs be behind the wall board?

-They say “Everyone does it like this, there is no need to reenforce down there. The rest of the shower wall is solid. We have no complaints from other customers. This happens sometimes.”

Tile Floor.
-I point out that the area 1′x1′ where they had to add matching tile, starting from scratch (studs) was bowed enough for a puddle to form and that some of the tiles were sticking up slightly and that the grout lines were uneven. I note that the original floor (the house was build in 1917) is flat and even. If they could do it right 100 years ago what can’t you?

-They say “It is an old house, things move, we can’t duplicate the mud work (?) they did on the floor. Almost no one does mud work anyways. Your lucking you got us. Besides it is only around an 1/8 of an inch anyways. Tile is also hard to work with and match. Sometimes things are uneven. Nothing is perfect.”
(The tile is around 1″x1″ and is an exact duplicate)

-I point out that they have a perfect example to go by, the original floor. If they can do it, the original builders, you can do it in this Modern day.

I was sure the contractor would understand and remedy at least some of the issues I pointed out but they brushed off most everything I said.
Basically I was stunned.

ASSUMING my complaints / grievance are valid i need to convince my wife that we are not being treated fairly. She is less nit picky than I am by a large measure. Are there tile guidelines, guilds, local organizations, standards, anything that I can use or do to back these guys into a corner and admit they have done a shoddy job and fix things.
I checked my neighbors recently done showers and they were not like this.

I can send pictures if you need a better idea of what I am talking about.

Thanks

Drew

Reply

Roger

Hi Drew,

Everyone does NOT do it that way, the studs should be chiseled out to make room for the liner behind the substrate or the studs above the liner should be shimmed out to keep the substrate flat from top to bottom.

It’s true that it should make it’s way to the weep holes when it gets through the tile and grout, but the majority of the water should shed from the tile layer, not the liner layer. The floor still HAS to be angled at 1/4″ per foot. And there HAS to be a preslope beneath the liner.

All the grout should be removed and redone, and caulk only at changes of plane, not in regular grout lines.

16″ o.c. studs is normal. This only ‘happens sometimes’ when the contractor doesn’t know what the hell they are doing.

The only reason they can’t duplicate the mud work is because they don’t have the skill to do so – I do it all the time.

You ARE NOT being treated fairly, you have a contractor with less-than-adequate skills for your installation and what seems to be a serious lack of knowledge. You can contact a tile forensic expert (yes, we have those) and hire them to look and the installation and document what is wrong with it, and take his ass to court.

Your first step would be to grab a copy of the tcna manual, which lays out acceptable guidelines and proper installation procedures for all types of installations here: https://www.tcnatile.com/handbook-all/910-2014-tcna-handbook-for-ceramic-glass-and-stone-tile-installation.html. Go through it and mark the pages which apply to yours (I can help you find them if you get stuck).

After you do that you can call him and start quoting that stuff, it may do the trick since he apparently has never heard of the manual. I WOULD NOT let him fix anything else, he’s not doing it correctly and may exacerbate the issues. Get a refund, in full, and hire someone who knows what they’re doing.

If doing that doesn’t prod him find a forensic expert.

Reply

Susan

I recently installed Rialto White Porcelain tile (purchased at Lowes) in my kitchen. I really love the tile, however not so much with the grout that I used which is Polyblend Sanded Grout (purchased at Home Depot) because Lowes did not have the color grout that I wanted. The first bag used seemed to go pretty well, but the second bag seemed to be very loose and I ended up with very uneven grout line depths. Hope this makes sense….pretty much, I have many low spots. I also have grout that is cracking and some chipping already. Any suggestions on what I can do about this? The install was approximately one month ago. I waited because everyone said to give the grout time to harden (approximately 2 weeks). I added sealer to the grout mix, but I have not sealed the grout yet with any of those products that are like a pen to go over the grout. Also, one last thing as if this was not enough…the tiles have pits that have grout in them, any suggestion for removing it? I would appreciate your suggestions/help. Thanks so much! ;-)

Reply

Roger

Hi Susan,

You added sealer to the grout??? What kind of sealer? If it was a regular tile or grout sealer then that is likely your problem. You should be able to get the grout out of the pits with a white scrub pad.

Reply

Roseann

I am laying out a tile mosaic. There are some large areas with no tiles because of the design. I don’t want to fill the areas with just grout. Any ideas like maybe glass balls or beads?

Reply

Roger

Hi Roseann,

You can get glass mosaics pieces separately online. Will that work?

Reply

Mary

Hi, my husband put a glass backsplash at his mothers house, he read the
directions wrong and grouted the backsplash and left it on all the tile over
night. How can we get this off without doing damage to the glass?

Thank you.

Mary

Reply

Roger

Hi Mary,

A plastic putty knife, normally found in the paint section, should take the grout off without damaging the glass.

Reply

Ruth

HELP! Moved into a home w/ large tile floor area (home 10yrs. old when we bought). Flooring looked beautiful, beige tile w/ tan grout. Knowing NOTHING about tile floors I was mopping fairly regular to keep clean. A year in, I started seeing cracking along edges of grout so I stopped wet mopping thinking water was seeping in. Now chunks are chipping out and there’s a dirty sandy grout underneath…looks like this tan color was “painted” over it. The underlying grout is cracked and you can seeing it’s pulled away from tile. If I stand or press on the tile it seems to move a bit, I can hear a crunching sound. This movement is in a couple spots (the rest of tile seems secure) but this “paint” is still chipping away everywhere! Can the individual loose tiles be fixed? And any idea about the whole grout/painting job in general? Floor getting worse day by day, hate for anyone to see. Tile in kitchen, eating area, laundry, entry from garage, gets heavy traffic. Love the ceramic tile but…bad grout, bad instillation, any hopes that it can be fixed and how??

Reply

Roger

Hi Ruth,

Individual tiles can be fixed, but you’ll likely end up with the same problem. There is something causing movement of your tile. It could be inadequate support from the framing, improper substrate, incorrect bonding of the tile, etc. There are a lot of potential causes, most of which require replacement of the tile and substrate.

If the grout over which they painted the colorant was not cleaned, new, or prepped properly then the colorant will not bond long-term. It may have been a case of simply painting over the grout rather than cleaning or repairing it. In that case the floor would likely need to be completely regrouted after the existing grout is removed.

Sorry, I know none of that is what you wanted to hear.

Reply

Catherine

The grout between the tile on both our bathroom floor and shower wall is uneven. Not only does it look visually unappealing, it also leaves sharp edges where I see and feel the sides of the tile. My father-in-law is the one doing the project and my husband doesn’t want to offend him by pointing it out to him. Can we go back and put more grout over the existing grout at a later date (quite possibly a month later)?

Reply

Roger

Hi Catherine,

If you do that you’ll need to remove all the existing grout to get the new stuff to bond.

Reply

Linda

Hi! Two days ago I grouted the backsplash in a home I am redoing. However, I don’t like the color after it dried (should have went with my first choice!!) Anyway, do I need to scrape the grout out (and if so, how do I do this), or can I do a light layer of the desired color on top of the current one. I’m going from a light tan to white. Thanks so much!

Linda

Reply

Roger

Hi Linda,

It needs to be scraped out. A thin layer will flake off within a couple of weeks.

Reply

Sarah

Hi! I think I already know the answer you will give me according to your previous posts, but I just want to make sure. ;) We have just put in porcelain tiles in our kitchen, which gets decent traffic because it is in the middle of the house… any way… I used Keracolor sanded grout, and I’m assuming because of the way I sponged it, it dips in a little. I would like the grout to be level with the tiles, probably because I’m afraid I didn’t grout it enough and it won’t hold?! I don’t know. I haven’t sealed it yet, so, can I mix some more grout and do a “second layer” over what I have just finished (about 3 days ago). Also, once I seal it, do I have to worry about mopping it too hard and the grout thinning over time? Sorry if these are silly questions, I’m just nervous that I’m doing something wrong! ;) Thanks!

Reply

Roger

Hi Sarah,

Nothing silly at all. The grout between the tiles will always dip a little bit, it doesn’t mean it won’t hold. It’s still bonded to the sides of the tile. If it dips too much you MAY be able to put more grout over it, but it would not guarantee a hold. If you want the grout lines higher you’ll need to scrape out the old. Mopping it won’t affect the grout at all.

Reply

Sarah

Hey! Thank so much for your previous reply/help. Ok, so I did end up getting all the grout done…. and I sealed it according to the directions on the sealant bottle. Now, as we walk across the floor, I hear cracking, I can see where the grout it coming away from the sides of some of the tiles, and where little chunks are coming out. From what I read on your site I didn’t mix it right, which is probably the problem. :/ What do I do now?? :( If I leave it like that will it cause any damage to the floor? Or is it more of a cosmetic thing? I do want to fix it either way, but does it matter sooner than later? Thanks! :)

Reply

Roger

Hi Sarah,

If it is the grout then it doesn’t really matter when you fix it, it won’t compromise the floor. It will need to be removed and replaced with properly mixed grout.

Reply

Linda

We just finished tiling our bathroom floor and we’ve noticed some of the grout lines came out looking half-filled or otherwise not perfect… how can we touch up the grout lines so they look like we knew what we were doing?

Reply

Roger

Hi Linda,

Scrape or scratch the existing grout to rough it up or remove it and refill the needed grout lines.

Reply

Monique

Let me first say I wish you lived in the Denver area and I could have hired you to do my shower tile. We had our fiberglass shower pan removed and replaced with tile. We then hired a glass guy to install a frameless shower door. Three days later we noticed a gap in the grout between the tile on the top of the bumper and the vertical tile of the bumper facing the inside of the shower. I have a feeling this was a result of the weight of the frameless shower door as the hinge was drilled into the tile of the bumper. I read your post regarding removing grout instead of just adding grout over the existing grout but my question is what type of grout to use. The existing grout line is very thin. Will it matter if I use epoxy grout if the rest of the grout is sanded or unsanded grout?
Thank you

Reply

Roger

Hi Monique,

It won’t matter at all. Epoxy is fine. It may look a bit different, but it makes no difference from a stability standpoint.

Reply

Vickie

Hi – It’s me again; I have another question. We have decided to enlarge a room that has a tiled floor. I am hoping to get my hands on the same tile, so that when we extend 2 of the walls of this room, we can continue with the same floor tile. My question is this: how do we prepare the current edges of the floor tile to accept the new tile? I hope I am making sense.

Reply

Roger

Hi Me Again,

Just remove the grout from between your existing tile and any that you remove. If you have full tiles along those edges you don’t need to do anything special to them.

Reply

Amber

We just recently built a new house and we have noticed several bubbles and cracks in the grout of the showers. The builder is sending someone out to fix it for the 2nd time. I’m just wondering what should I be making sure they do to insure it is fixed correctly?

Reply

Roger

Hi Amber,

That depends on why it’s doing that. The likely reason is lack of waterproofing. If that’s the case then nothing short of a full replacement will fix it permanently.

Reply

steve

We had a guy do a tile bathroom and the grouting has some gaps / missing areas that we want filled in. The grouting was done a couple days ago and has not been sealed. Is it ok to add more grout or should it be removed. I know as a general rule you want to remove old grout but i was just wondering if that changes since the grout is so new and has not been sealed.
thank you.

Reply

Roger

Hi Steve,

Since it’s just a couple of days old you MAY be able to get away with just adding more grout. I can’t guarantee that, though. It would be better to remove the affected areas and regrout.

Reply

Leave a Snarky Remark

***PLEASE READ THIS FIRST!***

If you have already posted a question about your project and you are leaving an additional comment or asking another question - please do so as a reply to my answer to your last question.

Below every comment is the phrase 'Please click here to reply to this comment', just click on that and leave your next question.

If you post an additional question here it will show up as a new topic and thread. I have over 15,000 comments on this site (seriously), I can not go through every one to find the project or question you may be referencing.

HELP ME HELP YOU!

Thanks.

;) :wtf: :wink: :whistle: :twisted: :suspect: :shades: :roll: :rockon: :oops: :lol: :lol2: :lol1: :idea: :guedo: :evilb: :evil: :eek: :dance: :cry: :corn: :cool: :censored: :bonk: :arrow: :D :?: :-| :-o :-P :-D :-? :) :( :!: 8)