How not to tile a shower...

[wkearney99]

If anyone's looking for a good tile forum, try John Bridge

There's a ton of great threads over there. 

There's likely more ways to lay tile than any other building material.  But you never, ever lay it straight onto wood without at least some sort of stabilizing and waterproofing material.  Wood moves too much and tile does not, so just a moisture barrier like RedGuard is NOT enough.  Likewise, tile and mortar are not 100% waterproof.  They're pretty good at resisting water going through them, but they're porous enough, and there's enough potential for cracks in grout, so make for some really ugly problems if you don't properly manage moisture.

 

[Michael Kellough]

If anyone's looking for a good tile forum, try John Bridge

There's a ton of great threads over there. 

There's likely more ways to lay tile than any other building material.  But you never, ever lay it straight onto wood without at least some sort of stabilizing and waterproofing material.  Wood moves too much and tile does not, so just a moisture barrier like RedGuard is NOT enough.  Likewise, tile and mortar are not 100% waterproof.  They're pretty good at resisting water going through them, but they're porous enough, and there's enough potential for cracks in grout, so make for some really ugly problems if you don't properly manage moisture.

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

 

[live4ever]

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

They are waterproof in the sense that water will not harm/deteriorate them, but NOT waterproof in the sense that they do not provide any barrier to moisture moving through to the wood, just like any other masonry/concrete/stone/grout. 

 

[Michael Kellough]

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

They are waterproof in the sense that water will not harm/deteriorate them, but NOT waterproof in the sense that they do not provide any barrier to moisture moving through to the wood, just like any other masonry/concrete/stone/grout.

So, do cement boards need to be installed over a waterproof membrane when attached to wood?

 

[live4ever]

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

They are waterproof in the sense that water will not harm/deteriorate them, but NOT waterproof in the sense that they do not provide any barrier to moisture moving through to the wood, just like any other masonry/concrete/stone/grout.

So, do cement boards need to be installed over a waterproof membrane when attached to wood?

I am no expert in what building inspectors would want as a minimum from location to location, but common best practice nowadays is to attach the cement board to the framing, and then apply the waterproofing membrane over the cement board (e.g. RedGuard or Kerdi or others).  Then tile over the membrane.  So the waterproof barrier is right behind the tile...the cement board never sees the moisture as long as the membrane is installed correctly.  The moisture that gets to the membrane via the tile/grout has a return path to dry right where it came from. 

A cheaper, slightly older but common practice (and flawed) is to place a moisture barrier (e.g. poly) between the cement board and the wood.  The flaw is twofold.  (1) The screws that attach the cement board to the wood framing are going to puncture the membrane and allow a path for moisture into the wood.  (2) Moisture that gets through the tile/grout and then through the cement board will collect at the poly - it won't be able to dry out as easily and collected water is a bad thing even if the cement board itself isn't harmed. 

 

[Naildrivingman]

Very few consumers are open to the "education"
………………………………………

Well, I guess I’m dealing with the few who are.  I rarely have a problem educating clients and if I sense early early on that I will, I don’t even proceed past a phone consult.  I’m not afraid to tell prospective clients that I’m not the right contractor for them.  I’d rather bruise my own pride now, than let them do it later.  Life’s too short for that.

 

[tjbnwi]

If anyone's looking for a good tile forum, try John Bridge

There's a ton of great threads over there. 

There's likely more ways to lay tile than any other building material.  But you never, ever lay it straight onto wood without at least some sort of stabilizing and waterproofing material.  Wood moves too much and tile does not, so just a moisture barrier like RedGuard is NOT enough.  Likewise, tile and mortar are not 100% waterproof.  They're pretty good at resisting water going through them, but they're porous enough, and there's enough potential for cracks in grout, so make for some really ugly problems if you don't properly manage moisture.

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

No, think about cement itself, it's not water proof.

 

[tjbnwi]

Not knowing much about the subject I have to ask, are the various cement boards waterproof?

They are waterproof in the sense that water will not harm/deteriorate them, but NOT waterproof in the sense that they do not provide any barrier to moisture moving through to the wood, just like any other masonry/concrete/stone/grout.

So, do cement boards need to be installed over a waterproof membrane when attached to wood?

Never ever install any tile substrate in a shower over any type of water/vapor barrier. NEVER.

Tom

 

[tjbnwi]

I don't use cementitous backer, I'm to old to be lugging that heavy stuff around. My go to is Schluter Kerdi board or Kerdi on walls. Floors get Ditra or Dirta Heat.

Tom

 

[Michael Kellough]

The Schluter system seems really well thought out.
I think I used some kind of Schluter mat on my tile floor in 1992 but haven't given tiling much attention since then.

How do you seal the edges of the waterproof wall membrane?
What are those square patches on the wall.

I hope you post more pictures of the process so I can learn something. Had some fun loopking at images of "dirt heat" 

 

[jimbo51]

Tom

The text below is from the Daltile website. It seems to contradict your advice or am I misunderstanding something.

Check to make sure that the cement backer board is sound after removing the old tile. If not, you'll need to remove the old and install a new backer board.

Apply a waterproof membrane to the backer board to ensure that water can’t seep through and cause damage.

 

[tjbnwi]

Tom

The text below is from the Daltile website. It seems to contradict your advice or am I misunderstanding something.

Check to make sure that the cement backer board is sound after removing the old tile. If not, you'll need to remove the old and install a new backer board.

Apply a waterproof membrane to the backer board to ensure that water can’t seep through and cause damage.

We'll skip the first line.

If you're referring to my statement about not installing backer over any water/vapor barrier their second statement agrees with mine. You install the waterproofing on the tile side of the board, not behind it.

Tom

 

[tjbnwi]

The Schluter system seems really well thought out.
I think I used some kind of Schluter mat on my tile floor in 1992 but haven't given tiling much attention since then.

How do you seal the edges of the waterproof wall membrane?
What are those square patches on the wall.

I hope you post more pictures of the process so I can learn something. Had some fun loopking at images of "dirt heat" 

The mat you used in '92 was the original Ditra.

Kerdi band and Kerdi corners.

Kerdi band cut to 5x5 squares, they cover the washer/screws.

I'm water proofing the shower that started this thread tomorrow in preparation of the water test. I'll take more pictures of the process as it proceeds.

Tom

 

[jimbo51]

"Never ever install any tile substrate in a shower over any type of water/vapor barrier. NEVER."

Ah. Tile substrate is where I misunderstood. Thanks.

 

[tjbnwi]

"Never ever install any tile substrate in a shower over any type of water/vapor barrier. NEVER."

Ah. Tile substrate is where I misunderstood. Thanks.

I choose the word "substrate" due to all the choices.

Tom

 

[Cheese]

I don't use cementitous backer, I'm to old to be lugging that heavy stuff around. My go to is Schluter Kerdi board or Kerdi on walls. Floors get Ditra or Dirta Heat.

Well I’m also well into a bath remodel and even though I’m probably older than Tom [poke] I am still willing to lug that cementious based product around. It’s just my knee jerk reaction to using a belt and suspenders approach. It’s also the difference between doing this stuff for a living and doing this stuff for fun. Bottom line is, I’m getting too old too fast to not ensure that every project I tackle will be the last time I need to touch it.

I concur with everything thing else Tom has stated and will be using Kerdi membrane over the cement board and using Ditra Heat on the floor. It appears to be a well thought out system.

There will also be no shower curb. Just another obstacle you have to hurdle.

 

[tjbnwi]

I don't use cementitous backer, I'm to old to be lugging that heavy stuff around. My go to is Schluter Kerdi board or Kerdi on walls. Floors get Ditra or Dirta Heat.

Well I’m also well into a bath remodel and even though I’m probably older than Tom [poke] I am still willing to lug that cementious based product around. It’s just my knee jerk reaction to using a belt and suspenders approach. It’s also the difference between doing this stuff for a living and doing this stuff for fun. Bottom line is, I’m getting too old too fast to not ensure that every project I tackle will be the last time I need to touch it.

I concur with everything thing else Tom has stated and will be using Kerdi membrane over the cement board and using Ditra Heat on the floor. It appears to be a well thought out system.

There will also be no shower curb. Just another obstacle you have to hurdle.

Why do you feel cement board is better?

Order the heat cable about 10% less than the heated square footage (don't go more than 10% less).

How are you doing the shower floor? Who's drain?

Don't skip the flood test.

Tom

 

[harry_]

Order the heat cable about 10% less than the heated square footage (don't go more than 10% less).

Tom

As in 100 sq.ft of floor = 90 lineal foot of cabling?

 

[tjbnwi]

Order the heat cable about 10% less than the heated square footage (don't go more than 10% less).

Tom

As in 100 sq.ft of floor = 90 lineal foot of cabling?

90 square feet of cabling.

The way the cable is figured;

total room square feet--

deduct the tub area, vanity area, toilet foot print, vertical buffer area

Example;

100 sq ft room

tub 15 sq ft

vanity 15 sq ft

toilet 2 sq ft

3" wall buffer--(we'll use 3" x 20 feet of verticals) 5 sq ft.

100-37= 63 sq ft of area to be heated.

Order a cable that will cover 55-60 sq ft.

Schluter has a calculator on-line for this.

Tom

 

[harry_]

Gotcha, Thanks.