Can I use old wetbed? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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Scott Bucks
03-03-2007, 02:37 PM
I am going to redo, using 12x12 ceramic tiles, my 2nd floor master bathroom, which is 23 years old. Forgive me if my terminology is off. I removed the existing 1 inch tiles and I believe I am down to the wet bed. The concrete appears to be in fair shape. A few divots, probably from my chisel and no large cracks. A few small hairline cracks. Can I tile directly over this and avoid removing the wet bed? And, some of the honeycomb/criss cross paper backing from the tile is embeded in the concrete - will new tile cement adhere to this? Thanks.


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03-03-2007, 04:33 PM
Its a mud bed, and yes you can re-use it. Try to clean the old adhesive up as much as you can with a floor scraper. That stuff is called "cut back."

Scott Bucks
03-04-2007, 06:01 PM
Thanks Scooter- I was reading other posts and I also did the "bounce" test and all went well. I tried to scrape the papaer backing out and not a lot came up, so I am hoping it will be OK. I was thinking about making a quick pass with a dremal.

Should I fill the divots as I tile or far enough in advance that the cement will dry? Scott

Tool Guy - Kg
03-04-2007, 09:50 PM
Welcome, Scott.

Those hairline cracks grabbed my attention. Did you happen to notice if there was ANY cracking of any groutlines anywhere before you removed those mosaic tiles?


Scott Bucks
03-05-2007, 05:20 PM
Hi Tool Guy-

There was absolutely no cracking in the grout lines. With the exception of one crack, I really have to look hard to find them. There are only a few divots, althought around the toilet soil pipe and in one corner I will have to add cement.

It occurred to me last night that when I remove the shower pan I may end up damaging the mud bed and have to remove it anyway.

My reluctance at removing the mud bed is that I seem to create more work for myself than I sometimes need to do. And, because the tile in the master bath and the bathroom on the opposite side of the room had good, uncracked floors, I thought I could skip the extra work. Also, I seem to see new houses with cracked tiles in them so I thought if the old floor was good, don't mess with it.

Scott Bucks
04-08-2007, 09:14 PM
Hello- I removed the old shower pan and am looking at door options for a 48 x34 or possibly 54x34 shower pan. Are there door options aside from twin slider doors? Is there a door system that uses a door that swings out (like a regular door)?

Also, if I deal with a 54 inch shower pan, it seems as if the twin slider doors are special orders at Lowes and HomeDepot and would cost noticebly more than a door system for a 48 inch pan. Is this true? Scott

04-08-2007, 09:22 PM
check out Wilson Glass ( Lots of different configurations to look at. :cool:

Scott Bucks
04-10-2007, 07:31 AM
Thanks for the info. I am going to look for other glass companies near me as well. Scott

Scott Bucks
04-11-2007, 05:58 AM
Hi- More shower questions.

1. My shower had tile going up the wall to about 6 feet high and then painted drywall the remaining 2 feet. When I removed the tiles, I cut out the tiled sections oft he wall and kept the 2 feet of drywall going to the ceiling. I plan on using CBU and want to place it up to the drywall and then seam the CBU and drywall together. I want to avoide tearing out all of the drywall. Does this make sense?

2. The studs are 2x3 and not 2x4. How big of a problem is this? I read on the Hardibacker website that they want 2x4s.

3. The 2x3s are in good shape expcet for 2 which have some cracking, but no bowing or any sign of distress. The old tile was sound na dnot cracked. Walls were firm. Problem?

4. I have been reading about and looking at niches. These also seem to be based on 2x4s. The wall wear the niche would be actually has some access space. Can I build another frame behinds my 2x3 to extend it out so it would be bigger?

Thanks! Scott

04-11-2007, 07:08 PM
Scott, there should be no problem stopping the CBU short of the ceiling. I don't see a problem per se with the 2x3's. Can't comment on the condition of the two studs with cracks without seeing them or your ability to build out the wall for the niche. You would be the best judge of that.


Scott Bucks
04-12-2007, 06:00 PM
Thanks Mike. This site is very helpful!

Question about deflecto. How do I know the joist lenght? I could not see how far it went. In the basement it was 13 feet, but I am dealing with the 2nd floor. Does length remain constant as long as the size/preimeter/shape of the house stays the same (with the exception of height).

Also, how do I determine the material used for the floor? It is 5/8 th inch wood. I would refer to it as plywood. It is not particle board. Does that mean it is douglas? Thanks!

04-12-2007, 06:36 PM
Douglas fir refers to wood type used in joists.The plywood is considered the subfloor.The joists will run from one end of the house to the other,what is on top the joists doesn't matter cause the joist is supporting them,it's what's supporting the joists that increases the the shortness of the span, or length of the joists running in midair,unsupported.

Scott Bucks
04-12-2007, 06:57 PM
I guess I still don't get it. The width of the entire house is 27 feet. How do I know what and where the joist is supported? If the floor previously supported a tile floor, would this continue to be true for the next floor?

04-12-2007, 07:05 PM
I believe Davestone is querrying a deflection issue with the floor joists

How long do they span and how far apart are they spaced?

04-12-2007, 07:06 PM
You'll have to look UNDER the flooring joists.The joists will run the entire length of the house or be supported at some point, which will shorten it's span.Think of a board laying on top of two blocks on the ground,that's essentially what the joist are doing.Even if it had a tile floor before, it doesn't mean it will support one without cracking now....

Scott Bucks
04-12-2007, 07:44 PM
Thanks for all of the help. Thanks for the read, Davestone.

Either I am missing something or my 2nd floor is about to collapse.

The joists are 2x8 and 16 inches apart on center. I used a flashlight and mirror and looked in the cutout for the shower drain and see no supports going across/between the joists. Does this mean they run 27 feet (there is a supporting network of beams)? Based on a 13.5 length, my defelcto would be 221. A 27 foot length is off of the scale.

If my delfecto score is low, or I am a complete idiot and never correctly figure my score, how can I improve the strength of the floor? Thanks!

Scott Bucks
04-14-2007, 05:21 AM
I looked at the floor below the bathroom, and I am guessing that there is a beam supporting the joists 14 feet out. I do this based on 14 feet being the length of the rooms below. If I am correct, my deflecto score is 200. How can I improve the deflecto score and/or what am I missing?

04-14-2007, 10:07 PM
You're on the right track Scott. Those rooms on the first floor immediately below the bathroom will be the key to understanding the unsupported span of your bathroom joists. The only walls we are concerned with now are those running perpendicular to the run of the joists. So if those first floor walls below the bath truly are 14 feet apart, then your Deflector score is indeed only L/200. And that is assuming the joists are either Doug Fir or South. Yellow Pine which is not a safe assumption. In your case for wood of unknown condition and species, the deflection numbers drop to L/153.

To improve those numbers you only have two choices and neither one is particularly attractive. Add a supporting wall or beam on the floor below to reduce that 14 foot span to at least 11 feet. Or tear open the ceiling below and add additional joists or sisters.