Caulking around a shower

[Lee R Batchelor]

Hi all. I'm new here and would really appreciate some advice.

I installed a shower about 5 years ago. It came with a base tray. The walls are single piece man-made marble. These walls sit on the inside lip of the base tray. I've re-caulked the shower twice and always ended up with mold in the corners of the walls and tray. Each time I remove the old caulking, there's water in the crack between the walls and tray lip. I'm trying to determine where it's coming from.

There are two glass doors - one fixed and the other slides on rollers. The fixed door is at the shower head end. The manufacturer says to not caulk any parts of the door on the inside of the shower, only the outside.

Is it possible that the water is seeping behind the marble walls where the door framing hardware is attached?
- or -
Am I using the wrong caulking technique? I have always applied the caulking and then rounded it inward with my finger. I watched a video about this and the fellow said that was the worst way to do it because it will always leak where the thin part contacts the wall and shower tray. Instead, he suggested using a 45 degree tool to create a more positive bond.

I suspect my issue is with the second one. I can post pics if needed. I really appreciate any opinions. Many thanks...

- Lee

 

[WorthFlorida]

It's always a mystery when trying to find how water shows up in places. Caulking when used in a bathtub/shower will always eventually mold even of there is no water behind the it. It is possible that its from condensation if this shower is on an exterior wall. Caulking does not last forever depending on it environment. Just follow the manufacturer's suggested caulking. Fill in the entire void and smooth out and it is true not to get a thin layer. Caulking and silicone always seem to pull away from from certain materials. I've had caulk completely pull away from a granite surface at a drop in sink rim in only a few months.

Do get it with Microban
https://www.homedepot.com/p/DAP-Kwi...Adhesive-Caulk-with-Microban-18872/100172358?

 

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[Lee R Batchelor]

Many thanks for the reply, WorthFlorida. You're sure right about water being elusive. I wonder what the logic is about not caulking the inside of the door frame. I suspect the water is seeping in from there.

 

[Jadnashua]

You might benefit by using some foam backer rod in the joint between the walls and the pan, then caulk it. A square, monolithic caulked joint tends to break at the weakest point. By using backer rod, that forces the caulk into an hourglass shape, which will stretch in the middle rather than pull the material off of one of the surfaces it is trying to seal.

One thing that often is a problem is when the pan is not properly leveled and bedded (if required). Non-level can cause water to pool. Improperly bedded, on many of the materials, can cause the pan to flex, putting more strain on the caulked joints.

While somewhat of a pain, after drying yourself, take another minute and wipe the shower walls and especially the joints to the pan. Mold requires three things, and you can control only one of them reasonably:
- moisture
- food
- mold spores

Drying the shower should prevent that for the most part, and in the process, wipe up some food. Many people do not use a ventilation fan, or if they do, don't leave it on long enough that completes the drying process. It's almost impossible to get rid of all mold spores. So, the first component is fairly easy, the second, a little bit harder (a periodic good cleaning of soap scum and water spots that help give things a grip will help).

 

[Lee R Batchelor]

Great advice, Jim. Thanks. I can do all those things.

The water that came out of the cracks after I removed the caulking was partially brownish in color, meaning it had been there a while. Some of the water was also clear and there was a fair amount, so I suspect it's a leak as opposed to simple condensation. The wall in question is on an inside wall and well heated. When I did the reno, I installed a Panasonic 110 cfm fan. The bathroom is quite small, so 110 cfm is overkill.

I leveled the pan as best as I could when I installed it. It sits on a bed of cement. The subfloor is 5/8 plywood (the real stuff - not the chip board) and the support system is floor trusses. These floor trusses are just like the roof truss - 2x4 with gang plates - not the chip board floor trusses, which are probably good too.

I still wonder why the manufacturer of the doors insists on not caulking the inside channels that contact the marble. I really suspect the water is seeping in from the channel and then along th shower pan lip. Strange!

 

[WorthFlorida]

Great advice, Jim. Thanks. I can do all those things.................I still wonder why the manufacturer of the doors insists on not caulking the inside channels that contact the marble. I really suspect the water is seeping in from the channel and then along th shower pan lip. Strange!

As you see caulking can trap water. No caulking water will be allowed to drain and air dry. I think water can enter the seal of the glass at the aluminum trim and work itself down to the bottom corners and drain out at the corner seams.

 

[Lee R Batchelor]

As you see caulking can trap water. No caulking water will be allowed to drain and air dry. I think water can enter the seal of the glass at the aluminum trim and work itself down to the bottom corners and drain out at the corner seams.

That makes perfect sense. I just finished peeling the old caulking away. I checked the level of the tray. It's dead on the money in all directions, so that's one headache we can eliminate.

There was less water on the side gaps versus the end gap where the shower head is but there was still some water. I suspect the water is getting behind the caulking by means of an incorrect application technique and the incorrect product. One other member, who has been a tile installer for 30 years, remarked that the GE silicon is not that good a product and that all he uses is Mapei caulking. I can order it through Lowe's here in Canada.

Shall I proceed on that basis?

Again, thanks for all the answers! I promise not to monopolize this forum too much longer !

 

[WorthFlorida]

Silicone has a few good applications but for the most part I try not to use it. It's why I prefer siliconized caulk. You get the best of both worlds and you can work it and clean up with water. Yes, Mapei makes good products. I hired a tiler and he used Mapei products. Our kitchen backsplash and the main bath is done with Mapei grout and thinset. I went to Lowes to get the product for him per our agreement.

 

[Lee R Batchelor]

Silicone has a few good applications but for the most part I try not to use it. It's why I prefer siliconized caulk. You get the best of both worlds and you can work it and clean up with water. Yes, Mapei makes good products. I hired a tiler and he used Mapei products. Our kitchen backsplash and the main bath is done with Mapei grout and thinset. I went to Lowes to get the product for him per our agreement.

Good to know. Thanks!

 

[Danny12]

Hi all. I'm new here and would really appreciate some advice.

I installed a shower about 5 years ago. It came with a base tray. The walls are single piece man-made marble. These walls sit on the inside lip of the base tray. I've re-caulked the shower twice and always ended up with mold in the corners of the walls and tray. Each time I remove the old caulking, there's water in the crack between the walls and tray lip. I'm trying to determine where it's coming from.

There are two glass doors - one fixed and the other slides on rollers. The fixed door is at the shower head end. The manufacturer says to not caulk any parts of the door on the inside of the shower, only the outside.

Is it possible that the water is seeping behind the marble walls where the door framing hardware is attached?
- or -
Am I using the wrong caulking technique? I have always applied the caulking and then rounded it inward with my finger. I watched a video about this and the fellow said that was the worst way to do it because it will always leak where the thin part contacts the wall and shower tray. Instead, he suggested using a 45 degree tool to create a more positive bond.

I suspect my issue is with the second one. I can post pics if needed. I really appreciate any opinions. Many thanks...

- Lee

Hi Lee,

A few months ago, I visited this forum to find more information about a similar problem I had, and I think your problem is very common. I recommend you visit this blog I saw, it's very informative and talks about your specific situation. Hope this is helpful.

Mold on Marble Shower

Constant water infiltration under the tiles causes mold on marble shower and damages the most durable marble. Here’s what to do about it.When you first see the tell-tale signs of mildew stain, or mold on your marble shower, you may think the problem is with whoever is cleaning it. So, you Google...

www.tersomr.com

Danny

 

[Jadnashua]

Mold growth requires three things, and you can only control two of them:
- spores (they're everywhere except maybe in a clean room)
- water
- food

So, to help minimize mold growth, things in a shower need to dry out in between uses, and many people do not use, if they have one, the exhaust fan long enough. Second, is the food...that can be in the form of soap scum, shampoo, conditioner, body oil, dead skin cells, etc..

So, if you want things to last longer, wipe the shower down when finished, otherwise, mold will eventually happen.