To Caulk or not to caulk


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Old 02-11-07, 07:24 AM
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To Caulk or not to caulk

Back in the day, I was told to use caulk where the tub or shower pan met the edge of the tile on the tiled wall. Now I am reading that the backer board should be caulked where it meets the edge but the tile should be set about 1/8" shy of the bathtub or shower pan curb and this area should be left free of both grout and caulk so that any moisture that gets behind the tile has a way to get out. Similar to having weep holes. While this does make some sense to me, I want to get some feedback from those with far more experience.
Thanks
 
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Old 02-11-07, 07:44 AM
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Been doing tile nearly twenty years and this is a new one on me, I haven't heard this one. I do leave the tile up about an eighth, but pack it with caulk when I'm done. I'd be afraid of things growing back in there if nothing else.
 
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Old 02-11-07, 09:01 AM
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You should caulk that area as Smokey said. The issue you raise is a good one however. Traditional shower construction with cbu walls requires a moisture barrier behind the cbu. Thats so moisture that gets through the tile, grout and cbu doesnt make its way to the studs, insulation etc, causing rot, mold and whatever else. Ive heard this question before - If the vapor barrier overlaps the tub flange or shower base flange and that area gets caulked, then where does the moisture go when it reaches the vapor barrier? Does it make its way down to the flange and just sit there since its caulked? A properly constructed shower shouldnt have steady streams of water making its way through to the vapor barrier. That shouldnt happen. What should happen is the small amounts of moisture that make their way though should be able to make their way back out though the cbu and grout joints when the shower is not in use. Does it happen exactly that way all the time? I dont know but it should? Excessive amounts of water cannot help but wind up on the floor somewhere, but if thats happening, then something else is wrong. I suspect this is one of the reasons why the industry seems to moving towards waterproofing showers with kerdi and other products. This issue is eliminated when you use kerdi, redgard, laticrete 9235 or other waterproofing products over the substrate. I wouldnt be surprised to see standards going in this direction in the future.
 
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Old 02-11-07, 09:59 AM
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Thanks to both of you for your feedback. One other question. While every one agrees that a vapor barrier is needed behind cement board, I have heard different opinions about the need for a vapor barrier behind the hardiboard product. What is your opinion? Also what experience is out there on the new GP DensShield Tile backer that does not require a vapor barrier?
Thanks,
 
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Old 02-11-07, 01:03 PM
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Originally Posted by joeperi
Back in the day, I was told to use caulk where the tub or shower pan met the edge of the tile on the tiled wall. Now I am reading that the backer board should be caulked where it meets the edge but the tile should be set about 1/8" shy of the bathtub or shower pan curb and this area should be left free of both grout and caulk so that any moisture that gets behind the tile has a way to get out. Similar to having weep holes. While this does make some sense to me, I want to get some feedback from those with far more experience.
Thanks
Something to keep in mind that is often overlooked:

I am in the maintenance and repairs business of rentals for the past 20 years with strong construction practice before that. Time and time again I see walls and floors rotting where the curb or tub meet the wall of the shower...and the floor where the curb or tub meets the floor. You may not actually see any water run out of the corner of these areas, either. What happens is that water gets behind the top edge of the curb or tub at that 1 inch or so flange, and races around the top and comes to where the wall overlaps the flange, at the side where you enter the tub or shower stall, and gets behind tile or finished wall and runs down behind there and rots that wall and maybe rots the floor.

On one job I had to redo, this silent rot literally ran under the linoleum and subfloor so badly that the nearby toilet was almost ready to fall through the floor due to this unseen rot! On another job, the water ran around the walls near the tub, and caused mushrooms to grow, high!, out of the crack between the floor and bottom of wall! I fixed these...and many others like it.

What you want to do when first installing the tub, and then resting the surround ontop of it, or with the curb, and then walling and tiling above it, is to sandwich caulk in between at the front edge so that any water running around the top of the tub or curb hits the caulk, like running into a brick wall, and then the water has to run back into the shower pan or tub, without secretly running behind the wall, and out.
 
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Old 02-13-07, 07:41 PM
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similar problem

We just bought a 3 year old home - the 'material' between the ceramic tile and shower pan appeared to be crumbling. I was not sure if it was grout or caulk. When I removed it, it had a gritty texture to it. Went to Home Depot and was sold a product that was a grout with silicone, in a squeeze tube similar to caulk. Cleaned out all the old material and installed this product. After allowing 3 days to cure, I assumed it was dry. Used the shower twice before I noticed that the product seemed to dissolving into the pan. To touch, it seems like it never set. The gap between the shower pan and tile varies around the shower - as small as 1/8" to as large as about 3/8' possibly more. I removed all of this product - what a mess. Should I use silicone caulk? Or do I need a professional to look at this problem? If so, what type of contractor am I looking for? Thanks.
 
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Old 02-13-07, 09:59 PM
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Does the container packaging the material you used refer to it as any sort of premixed grout? If so, that's the problem. Remove it and thouroughly clean the area of any residue. Go to a real tile store and get caulk made for this job. Every color of grout made has a corresponding color matched caulk to go with it made for the area you describe.
 
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Old 02-13-07, 10:38 PM
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I know a bit off topic but wanted to mention it anways...when caulking a fiberglass surround on top of a tub make sure you use ploymerseal tub and tile..regular tub and tile....isnt rated for fiberglass
 
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Old 02-14-07, 03:42 AM
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Ighenry: What you used was a color coordinated latex caulk, primarily used around countertops and the like. Latex is never used in a wet area, as it will (as you found out) dissolve due to its water borne properties. A good product, among others, is GE Silicone II. But your surfaces must be completely dry before application, or mold will grow behind the silicone. I usually dry the areas with a paper towel and then set a fan on it for a day b4 I silicone.
 
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Old 02-14-07, 05:31 AM
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If there are areas that seem deep - about 1/2", do I need to apply some silicone caulk, allow it to cure before applying another layer over top to finish? Or can apply as much as is needed, and allow extra time to cure?
 
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Old 02-14-07, 06:43 AM
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When you see what you describe as happening, most likely you have tile on sheetrock in the tub area. The sheetrock gets soaked as it wicks up water from the tub lip or through failed grout lines. Anything you put in there is not gonna work unless you solve your problem until you solve the wet sheetrock problem. As Chandler pointed out, it has to be dry. Water will continue to seep out the back at a fast enough pace to wash, melt, dissolve (whatever you wanna call it) anything you put in there. It has to dry out first and that can take a long time. That sheetrock could be wet from the tub flange to a few feet above. Being trapped between the tile and the wall behind it, it has no where to go. Sometimes cutting a whole in the sheetrock from the other side of the wall in another room and running a fan for some time helps to dry it out. You also have to find out why its getting as wet as it is, cause continued use of that shower will cause the same problem if not fixed. You may also have to face the fact that the shower may be reaching the end of its useful life. Ugly thought but it may be the case. My experience tells me that once tiled sheetrock walls get wet, the shower is not long for failure.
 
 

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