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Caulk or Grout? Change of plane shower stall, tile to base [PICS ADDED]

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  • Jan 15th, 2013 4:00 pm
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Caulk or Grout? Change of plane shower stall, tile to base [PICS ADDED]

Hoping someone with experience can lend support.
Fairly new home (5 years), noticed too much mold building up at the base of my shower stall.
I don't have a picture, but let me describe it. It's a shower only stall, the base is premade plastic/fiberglass, with tile everywhere else.
There was grout in between where the tile meets this base, plus caulking on top. This joint is roughly 1/2 to 3/4" I believe.

I thought that for this kind of joint, you would NOT use grout, caulking only. Could that be why this happened so new into home ownership?
The grout behind the caulking was cracking and its not connected (I can pull it out with a screw driver, etc). I have already removed the caulking on top of this grout line.

I'm not concerned about leaks, because of the design of the base, it has a tall lip behind the tile line. I do, however, want to repair this properly.

Is it best to REMOVE all of the grout, let dry for say 48-72 hours, and apply a silicone caulk to the joint?
If that is the best action, how does one make a 1/2 to 3/4" bead of caulk LOOK GOOD?! - I'm used to the very small joints, windows, etc, but this is a rather large bead to apply. And would I apply the caulk as far back as the lip of the base - or just enough to make contact between the base and the tile above it?

If you need pictures, I can add later when I'm home. If this is enough to offer advice, I GREATLY appreciate it!
Let me know if you need more info.

THANKS!!
OH

EDIT2. Here is the picture close up of grout/mortar removal. Not as deep as I originally thought, perhaps just the silicone alone will not be an issue. However, what about removing the layer of grout/mortar left on the exposed under-edge of the tile? Don't want to force this too much and disturb the tile
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Jan 18, 2004
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i feel they put grout so they have a base to put the caulk on. i think you need to fix the movement problem before reapplying grout/caulk. I'm assuming it moved and the caulk ripped from the tiles?

Pictures would help understand the joint better.
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Yes, remove all the caulking and grout and redo it in 100% silicone, there are ones that can be purchased to match the colour of the grout if you prefer. I am suprised that the spacing is so large, normally it's the same size as the rest of the tile/grout spacing which is usually around 1/8" to at most 1/4". Also check to see if the floor pan moves to create a slight opening between the pan and first layer or tile. In other words, add weight to the pan so it's at it's lowest point when siliconing. If installed properly in the first place, there should be no movement at the perimeter.

Since you have such a large gap, I'd purchase a plastic applicator that helps smooth out the silicone when appling and also tape around the edges to get a clean finish.
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Mold buildup wouldn't be due to the grout there. Most likely, they didn't use the proper caulking, or didn't apply it properly so water doesn't have a place to settle on the caulking.
Remove all the caulking, and then reapply with a good silicone (GE Silicone II is what I use).
I don't have any tips on how to make a large gap look good. I had a large gap to seal as well and it doesn't look great after it has cured. Looked better when I was smoothing it out and it had just been applied.
You would want to make sure water can't get in there, so you would want the caulking to go a decent amount onto the tile and then lead off onto the base as well.
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Mr Nobody wrote:
Jan 2nd, 2013 10:41 am
i feel they put grout so they have a base to put the caulk on. i think you need to fix the movement problem before reapplying grout/caulk. I'm assuming it moved and the caulk ripped from the tiles?

Pictures would help understand the joint better.
Well, the movement just seems like a natural flex of the base. Nothing major.
The caulking was actually intact but I started to notice more and more mold. Perhaps with my cleaning of the current caulk line I may have opened up very small openings where water was getting through and not drying up. I decided to remove the caulk and reapply my own, and that's when I saw the cracking grout behind it. I don't think its cracked because of any major movement, just not the proper material to use on top of a plastic/fiberglass surface.

I will attach a photo later today.
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Maymybonneliveforever wrote:
Jan 2nd, 2013 10:43 am
Yes, remove all the caulking and grout and redo it in 100% silicone, there are ones that can be purchased to match the colour of the grout if you prefer. I am suprised that the spacing is so large, normally it's the same size as the rest of the tile/grout spacing which is usually around 1/8" to at most 1/4". Also check to see if the floor pan moves to create a slight opening between the pan and first layer or tile. In other words, add weight to the pan so it's at it's lowest point when siliconing. If installed properly in the first place, there should be no movement at the perimeter.

Since you have such a large gap, I'd purchase a plastic applicator that helps smooth out the silicone when appling and also tape around the edges to get a clean finish.
Well, adding my own weight would add that 'flex', which stated above, it VERY minor. I presume it doesn't need to be a major move to disjoin grout where it shouldn't be.
I do have the silicone ready to go, since I was expecting a simple application, but then was confronted with this.

Perhaps there is a type of mesh one can add to the gap before siliconing? I have to re-read the silicone label, I think I recall seeing something about that if the gap exceeds a certain size, maybe anything more than 1/2"
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goofball wrote:
Jan 2nd, 2013 10:44 am
Mold buildup wouldn't be due to the grout there. Most likely, they didn't use the proper caulking, or didn't apply it properly so water doesn't have a place to settle on the caulking.
Remove all the caulking, and then reapply with a good silicone (GE Silicone II is what I use).
I don't have any tips on how to make a large gap look good. I had a large gap to seal as well and it doesn't look great after it has cured. Looked better when I was smoothing it out and it had just been applied.
You would want to make sure water can't get in there, so you would want the caulking to go a decent amount onto the tile and then lead off onto the base as well.
That's the silicone I have ready to go. I wanted to get the 10 year rated version, but the color I need is only available in the 5 year mold protection.
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Adding your own weight would only be helpfull when you're in the shower stall, I'll assume you don't want to remain in there till the silicone is completely dry? In other words, if there is movement, then it will shift when you exit the shower stall. Did you ensure the silicone you purchase is 100%. I prefered not to use mesh, what I do when there is a large gap is apply 50% with one pass, then start at the beginning with the next 50% so that it has a good based to be applied against. They key is how to cut the tip of the silicone tube as when as the hand/finger and amount that comes out of the tube. In other words, make it a smooth process and go slowly.

As for adding the weight, technically there should be no movement if the shower was installed properly.

EDIT:

I have seen tile setters mix a portion of dry grout to the 100% clear silicone to achieve the exact colour match, then apply it with the use of a grout bag.
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Maymybonneliveforever wrote:
Jan 2nd, 2013 11:07 am
Adding your own weight would only be helpfull when you're in the shower stall, I'll assume you don't want to remain in there till the silicone is completely dry? In other words, if there is movement, then it will shift when you exit the shower stall. Did you ensure the silicone you purchase is 100%. I prefered not to use mesh, when I do when there is a large gap is apply 50% with one pass, then start at the beginning with the next 50% so that it has a good based to be applied against. They key is how to cut the tip of the silicone tube as when as the hand/finger and amount that comes out of the tube. In other words, make it a smooth process and go slowly.
Oh, I thought you meant only during application, not also during curing.
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Mould in a shower stall can be resolved by shower stall maintenance/useage. Yes, tiling the shower stall totally and getting tempered glass panels will give the mould less edges to grow. But the silicon will deteriorate, grout will still change colour and mould still grows.

Understand mould will only grow in very humid situations. (ie. try to find mould in a desert.)

Does OP have a bathroom exhaust fan? If yes, is it on during shower and 15 minutes after show to remove the humidity? Also, does OP leave the glass door open so as to not trap the moisture in the shower stall after a shower? I also find rinsing the shower stall walls and glass at the end of the show helps keep the shower clean (my shower stalls all have hand held attachement).

Personally, I go further, I use a glass squeege to clean the glass, then use a sponge to dry the title/ledges/edges at the bottom of the show. If there is no moisture, mould cannot grow. After 5 years, the shower stall still looks new. (Also, wipe the chrome surfaces, handles, facets etc.)

http://www.homedepot.ca/product/deluxe- ... ome/946518

This is much cheaper than renovating a shower stall.
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I'd remove any existing caulk, let it dry (I left mine dry for half a day, then used a heat gun on my tub, but I'm not sure whether it would damage your stall). Then I recaulked with GE II.

There was some slight cracking in the exposed mortar (no grout in my case) so I didn't remove it. I think it's okay as long as it isn't loose. There was a bit of mold though.

I used to use those caulking tools (a curved 90-degree piece of Teflon with a handle) but I just use a wet finger now-a-days. Clean the finger on paper towels often when caulking and you should be okay.

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[OP]
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Busybuyer888 wrote:
Jan 2nd, 2013 12:20 pm
Mould in a shower stall can be resolved by shower stall maintenance/useage. Yes, tiling the shower stall totally and getting tempered glass panels will give the mould less edges to grow. But the silicon will deteriorate, grout will still change colour and mould still grows.

Understand mould will only grow in very humid situations. (ie. try to find mould in a desert.)

Does OP have a bathroom exhaust fan? If yes, is it on during shower and 15 minutes after show to remove the humidity? Also, does OP leave the glass door open so as to not trap the moisture in the shower stall after a shower? I also find rinsing the shower stall walls and glass at the end of the show helps keep the shower clean (my shower stalls all have hand held attachement).

Personally, I go further, I use a glass squeege to clean the glass, then use a sponge to dry the title/ledges/edges at the bottom of the show. If there is no moisture, mould cannot grow. After 5 years, the shower stall still looks new. (Also, wipe the chrome surfaces, handles, facets etc.)

http://www.homedepot.ca/product/deluxe- ... ome/946518

This is much cheaper than renovating a shower stall.
Good tips. Follow most.
Initially when I would clean the mould, it was surface mould (on TOP of the caulking). I may have been too aggressive when cleaning it off and taken off caulking with it.
Nothing major, but this has lead to this so I'm glad I can at least resolve this now, on my own.

Squeegee glass surface after shower? Yes.
Exhaust fan on for at least 10 min after? Yes.
Glass door open after shower? No.

I would sometimes squeegee the tile walls as well as the joints at the base.

I would say I've done more than most people do to maintain the shower, so I was not happy to see the mould growth. But all I can do now is fix what I got.
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t3359 wrote:
Jan 2nd, 2013 1:39 pm
I'd remove any existing caulk, let it dry (I left mine dry for half a day, then used a heat gun on my tub, but I'm not sure whether it would damage your stall). Then I recaulked with GE II.

There was some slight cracking in the exposed mortar (no grout in my case) so I didn't remove it. I think it's okay as long as it isn't loose. There was a bit of mold though.

I used to use those caulking tools (a curved 90-degree piece of Teflon with a handle) but I just use a wet finger now-a-days. Clean the finger on paper towels often when caulking and you should be okay.

bjl
Forgive my ignorance, is there a difference between the grout and mortar? At the base of the shower, the color appears different then the grout all over the shower tile. Would it matter if this is mortar instead of simply grout? As I said, I will show pictures later this evening.
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I've added photos to the first post.
This was BEHIND the caulk that I already removed.
Just to confirm, this is what I need to remove, correct, and apply the silicone only at this point.
I'm not sure if its grout or mortar, as it is dry, but still darker than the surrounding grout. Don't want to remove it if it has a purpose.
Also, I need to fix my eyes, as the largest width of the joint is LESS THAN 1/2" inch, so applying 100% silicone to the entire joint shouldn't be an issue.

Thanks for advice. Hopefully the pics help.
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From the pictures, I see the situation. This is a bathtub situation. Very typical.

I'd remove the grout from the bottom. That grout already is laced with mould. Clean the tile edges with Tilex (anti-mould formulation). Let DRY, DRY DRY. Maybe even 1/2 hour around tile/tub with hair dryer.

I'm not sure if OP should reapply a new grout + silicon afterwards or just silicon.

Since the original grout already has mould, applying silicon ontop, will not help. Mould will grow without air and would of rotted away the silicon from the back. Then water could further seap in to add the the mould growth. (This is why OP was able to clean away the silicon/cauking.)

This is a very typical problem, as grout is very hard to keep clean. Applying caulking/silicon ontop of cracked grout is the first thing we do. But it only works for short time before it becomes loose or mould grows from under it.
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