View Full Version : q on rebuilding tub surround

Richard S
03-09-2005, 10:21 PM
This weekend I tore out my tub surround down to the studs, which thankfully was a lot easier than I feared. I've got some questions regarding preping it for 1/2" cbu - not all of them tile related.

1. Furring out the studs so the cbu lays flat over the lip of the tub flange. The furring will need to be anywhere from 1/8" to 1/2". Are these std items at HD or do I have to rip my own? Also, after furring it out, how do you get the cbu to line up flat to the drywall it meets up with on the side of the shower - won't there be a difference is "thickness" due to the fact that the cbu was furred out from the studs.

2. I plan to insulate all wall cavities - even inside ones for soundproofing. There's some original wiring (about 37 yrs old) and the insulation on that wiring is in excellent shape. Is wiring that old designed to be ok with being encased in insulation? I don't want to waste either my time or money if I don't have to replace it.

3. I was able to keep the corner bead that I wanted, but in some areas the drywall fell away leaving just the corner bead with no supporting drywall behind it. I'm trying to avoid rebuilding this corner as I'm not sure I can make it look as nice. Any advice on how to handle. Or is it better to just take the corner bead out & rebuild it once all cbu is on.

All comments & suggestions welcome & appreciated.


03-14-2005, 02:21 PM

I had the same questions about furring out the studs. I went to HD and all they had to provide were some heavy 1/8" cardboard strips - not exactly what I was looking for. What I did find that worked better was that Lowe's carries what they refer to as a 1/4" wood lathe which is 2"X1/4"x4'. In some cases I needed to double these up as apparently not all studs are inline with the others. The lathes came in a 50 bundle and my local store had them in the garden department :confused: .

For my shower downstairs I had furred out the studs but then had the same uneven transition as you are experiencing with your existing drywall. I ended up using a mud cap tile that hide the step down to the existing drywall. For my upstairs tub I simply ripped out all the textured drywall and furred out the adjoining sidewall and went with a smooth surface all around (easy for future repairs). :)


Richard S
03-14-2005, 08:44 PM
Thanks for your reply. Strangely enough, I was at Lowe's on my lunch hour today. I didn't know to refer to the furring strips as wood lathe so I couldn't find that today. I'll go back tomorrow & get it. I'll need that on the wet wall. I did pick up those 1/8" cardboard strips which will work perfectly on my long wall - but they're very pricey for cardboard.

My back wall is another matter as the tub angles away from the wall slightly & would need to be furred out from 1/4" to 1/2". I've been doing some research since my post on a tile site, www.johnbridge.com. An alternative is to have the cbu only go to the top of the bathtub flange, caulk it, float the tile over the flange with some thinset & caulk the bottom. This works with tiles 4" & larger as the tile is only floated 1/2" at most. In thinking back to my own tub - this is how the original builder did it 37 yrs ago & it was bone-dry behind the drywall when I demo'd it. The reason I'm leaning toward this is that my door is so close to the bathtub that the tile will butt up against the doortrim which limits my options. Therefore, although the mudcap would work great if I only had another 2" to work with, it won't work in my situation. And although I don't mind redoing the drywall, matching texture is not my strong suit.

The problem is that my new tile is 3x3, so I'll need to go back to that forum & see if I can still use that option. If not, I'll have to demo the remaining drywall on that wall as you did. So, if you're still with me after that long ramble :), I've got a few more questions.

1. did you have your bathroom door on that wall & if so, how did you deal with the increased wall thickness & the door jam. In looking at my door jam (which I'll be replacing when I get my new door), it seems I'd need to special order a thicker jam to compensate.

2. how did you deal with outlet boxes. did you have to move them out by 1/2", or just use longer screws to secure the face plates.

As you've been there, done that, I really appreciate your insights into my situation.


03-14-2005, 11:16 PM
Most wood window manufacturers (even high end such as Marvin) simply extend out the jambs with wood strips (1/2 x 1/2, 3/4 x 1/2, etc - "jamb extenders" they call them) if you order wider than standard (4 9/16") jambs. I don't know why you couldn't do the same with your doors - get 1/2 square stock in the molding aisle. As to the outlet boxes, you can get 1/2" screw on extension flanges, but if the exposed wall under the plate is nonflammable (tile and grout) then I don't think you have a code or other problem. Just use the longer screws. Ask your local inspection department if you want the straight scoop in your area.

Richard S
03-14-2005, 11:23 PM
thanks, much appreciated.

03-15-2005, 09:33 AM

Fortunately, when I took my wall down I did not have the same issues with a door/outlet to work around. I personally got lucky as my tub is in an alcove and the wall I took down is across from the doorway. :)

With regards to your issues with the cbu and the tub surround...I don't know if anyone else has tried this but if you were to route a 1/4" groove along the bottom to fit over the surround, it may give you the extra bit you need for your 3"x3" tile without having to furr out the studs to take the pressure off the surround.

Richard S
03-15-2005, 08:09 PM
Thanks for getting back to me. I finally heard back on my other post & spoke with some people and I should be able to float the tile over the flange with no problem. The irony is that I may have to return the 3x3 tiles & buy the larger size due to a completely separate issue. But that's life.

Thanks again,

03-06-2007, 07:55 AM
I have a similar problem with furring out the studs to the level of the tile flange. The resulting wall will not be flush with the sheetrock outside the tiled area.

I am considering the following possibility. Attach 1/2" backer board directly to the studs. On the last row of backer board above the tile flange, use 1/4" backer board down flush to the flange. Using appropriate screws and adhesive, place another 1/4" piece of backer board on top of the previous piece, that continues on past the flange down to the appropriate level for the tile.


03-06-2007, 08:20 AM
cheaper is to use only 1/4" backerboard everywhere, and just rip furring strips and put one or two on top of the stud.

1/4" backer CBU board is approved for walls. That used to be the only thickness available, once upon a time.