Bathroom tile advice

[JohnFLi]

I am re-doing one of my bathrooms. I have already removed the fiberglass shower stall and linoleum. I have also removed the 1/2" particle wood that was under the linoleum. I have the floor down to the 2x6's that are on the joists.

The attached image is the layout of the bathroom (not large huh? lol)
I want to do the shower walls and the entire floor in tile (already have the tile picked out)
I will be putting a linear drain on the far side of the shower (at the wall at the top of the pic)
I am also going to make it curbless, with that, I was also thinking about extending the slope another foot outside the normal shower area (for any extra spray from teh shower.) Makeing the slope area 3'x4'

So my question is this: How far down do I need to lower the floor in the shower area for the shower pan?

Also, for shower pans. I have seen 2 different setups.
1) cement morter/water proof liner/morter/tile
2) cement morter/water proof liner/tile.

For the liner, I will be using the roll-on type, RedGuard.

 

[dovetail]

There was no need to remove the subfloor. If it was 1/2" it would have needed beefed up. Code for a sub floor is 23/32". 2x6 joists will not meet the L/360 deflection requirements for tile. 2x8 are the minimum requirement for tile so you may have to alter the framing. Typically a curb is installed over the existing framing, standard is 3 - 2x4's stacked on top of each other (4 1/2") then the backer is cut to allow for an additional inch (void is filled with dryset mortar). If you are trying to create a step down effect drop your 2x8"s down 6 1/2" . They will need to be reinforced below with a girder at either end (dbl 2x10 should suffice, reference local codes for footing requirements).

Red guard is not a liner and should not be used as such. It is a membrane. Your liner is a 40 mil pvc liner:

The proper sequence is mortar/ liner/ mortar/ red guard (if used follow manufacture instructions)/ tile.

Do not use drywall as a tile backer for the walls. Use either James Hardi fiber cement board or durock.

 

[JohnFLi]

Thank you for your reply. According to http://www.custombuildingproducts.com/tds/tds-104.pdf section 3, it does list redguard as a shower pan liner. Also, for more clarification...the joists are 4x8, or 4x10 (i havent measured yet) the subfloor is 2x6, not plywood. But, I do have a much more important questions though.

No matter what I use for a liner, redguard, or a 1 piece liner, it's the thickness of the pan itself, and the rest of the floor. Like I have mentioned, what I tore up was 1/2" particle wood that had linoleum on it. so if I used Hardi backer on the floor, I would need the 1/2" thick one correct? Or would the 1/4" hardi board be fine since it would be on 2x6's? With that, I want the shower itself to be a walk-in (curbless).
How would I be able to have concrete/liner/concrete/tile with the proper slope without needing to remove the subfloor and part of the joist?


Re-enforcing the joist isn't an issue as I have a fair amount of space under teh house. enought space to where crouching is a little tight, but laying down is to far lol
I was planning on using a concrete base with 4x4 posts on either side holding it up. Like they use for making decks. Also, from the previous shower, the fool had drilled a hole through the joist to run the drain pipe ( i meant to include a pic of that) and that drain leaking for years is what prompted me to start this project in teh first place.

 

[dovetail]

If your concern is reinforcing the floor (adding strength) then I would recommend 5/8" or 3/4" plywood over the existing subfloor. It doesn't sound like you need that reinforcement though. 4x8 joists with 2x6 sub floor should be sturdy enough to support the tile. Remember that hardiboard is an underlayment and does little to add strength. Typically 1/4" is used on the floor and 1/2" ( it's actually 3/8" thick) on the walls. For your particular application I would recommend schluter ditra over 5/8" plywood..

http://www.schluter.com/schluter-us/en_US/Shower-System/Waterproofing/c/SS-W

You will need to slope the entire floor towards the drain and sanitary tile will be a must. To slope the floor your best bet is to use dry set mortar (topping compound) and create the slope over the subfloor (think traditional mud floor) then install the ditra. You can check this site out for some drain options:http://infinitydrain.com/

You are allowed to drill or notch the joists. Here is the International building code (model code) for your reference:
2308.4.2.4 Notches and Holes
Notches on the ends of joists shall not exceed one fourth the joist depth. Notches in the top and bottom of the joists shall not exceed one sixth the depth and shall not be located in the middle third of the span. Holes drilled in the joists shall not be within two inches of the top or bottom of the joist and the diameter of the hole shall not exceed one third the depth of the joist.

4x4's are not used to support decks anymore. You may see them used on stringers for mid span support or small bump outs but 6x6 is the minimum post size to meet typical design load requirements. This is due to the downgrading of tensile strength capabilities of lumber by the ALSC, USDA and AWC in fast growth growth lumber.

 

[JohnFLi]

Great, thank you for your reply. I was thinking that for the 'regular' part of the floor I would use 1/2" cement board, just to take up the space the 1/2" particle board was using before I yanked that out.

For the pan, I know it needs to be lower. But how thick do I need to make it? Thats my biggest question. I know I need 1/4" per foot slope. The drain will be on the far side, so It will need to be 3/4" lower than the rest of the floor. BUT (big but) I will need to notch out some of the joist because I know I will need a layer of 3/4" plywood (if not 2 layers), then morter on top of that.
just the plywood and slope, that makes it 2 1/4"...Just cutting the 2x6's isn't going to be enough Am I explaining it right? Sometimes things make sense in my head, but not to others (character flaw I suppose)


In the picture, you can see a little of where the old drain was, the 2x6's and a little of the joist under it.

 

[dovetail]

If you are referring to the mortar it should be 1 1/4" thick at the lowest point. If you are asking about the curb height IRC P2709.1 states the minimum curb height shall not be less than 2 inches when measured from the top of the curb to the top of the drain. I would reinforce the joists (dbl header at cut supported by typ pier construction) and cut out the area for the drop down floor I needed/ frame out a girder (support with piers) and frame a new floor at the level I need rather than compromise the structural integrity of the joist system as a whole.