Hello NG,

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

Floor is concrete, bottom floor of 2 stories.

What say you?
--
Cal

Cal Dershowitz wrote:
Hello NG,

I'm tiling a very small quarter bath (shower) in the wet part of
Oregon. In other places, I've thought that the expense of Durock
wasn't worth it, but I'm leaning toward recommending it for this job.

Floor is concrete, bottom floor of 2 stories.

What say you?

After the green board fails and the tiles fall off, you'll wish you had used the
Durock. At least I did. It's a tiny cost compared to replacing the whole tile
job.

| I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
| In other places, I've thought that the expense of Durock wasn't worth
| it, but I'm leaning toward recommending it for this job.
|

I wouldn't tile on drywall even in a dry room.
It's just stuck to paper. In the 80s, before
concrete board and after metal lath was common,
most tiling was either on plywood or drywall. The
former would pop off due to expansion/contraction,
while the latter had a short life expectancy - often
less than 10 years, depending on how carefully one
caulked to keep water out of the wall.

I only tile on concrete board with thinset. It's
more work than using tile mastic and/or drywall,
but the result is a mortar wall that will last.

Side note: I've noticed that greenboard is no
longer grayish inside, and sometimes comes as
"purpleboard". I'm curious whether anyone knows
the story there. I thought greenboard probably
had tar to make it water-resistant, and that maybe
that was banned, but I don't know.

On 11/01/2015 12:50 AM, Cal Dershowitz wrote:
Hello NG,

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

Floor is concrete, bottom floor of 2 stories.

What say you?

IMHO the only choice you have available is between durock or hardibacker.

Jon

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

I used Hardibacker for our showers. It's thinner and easier to cut.

The backerboard is a minimal cost compared to the rest of a tiling project.

Do it once, do it right.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com

On Sun, 1 Nov 2015 00:50:35 -0700, Cal Dershowitz
wrote:

Hello NG,

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

Floor is concrete, bottom floor of 2 stories.

What say you?

I doubt the code would even allow green or purple board in a shower
and certainly not below 4 or 5 feet.

On Sun, 1 Nov 2015 16:41:03 -0000 (UTC), HerHusband
wrote:

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

I used Hardibacker for our showers. It's thinner and easier to cut.

The backerboard is a minimal cost compared to the rest of a tiling project.

Do it once, do it right.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com
Do it once, do it right. Use Kerdi (Shluter system)
Either standard Kerdi over whatever wallboard you want to use, or
KerdiBoard. You don't need soncrete backer with Kerdi, and you use
thinset - it is totally waterproof and pretty well goofproof. It is
not particularly cheap, but good seldom is. It has a handy "grid" for
helping to keep the tile-job square. They also have KerdiDrain for the
bottom of the shower (pan) to use with Ditra to make a waterproof
shower pan.

On 11/1/2015 8:48 AM, wrote:
On Sun, 1 Nov 2015 00:50:35 -0700, Cal Dershowitz
wrote:

Hello NG,

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

Floor is concrete, bottom floor of 2 stories.

What say you?

I doubt the code would even allow green or purple board in a shower
and certainly not below 4 or 5 feet.


Alright, it's between durock, hardibacker, and plywood.

Would plywood have to be treated?

How thick on the durock?

How thick on the hardibacker?

Small shower....
--
Cal

| Alright, it's between durock, hardibacker, and plywood.
|

No, it's not. Read my post. It's
between hardibacker and concrete
board.

On Sun, 1 Nov 2015 21:40:16 -0500, "Mayayana"
wrote:

| Alright, it's between durock, hardibacker, and plywood.
|

No, it's not. Read my post. It's
between hardibacker and concrete
board.

Or any of the above with the shluter system

Cal is 100% right to look at Kerdi. Mapei makes a similar product, but
the Kerdi has it all.- at least make yourself aware of the product:

http://www.schluter.com/8_4_kerdi_shower_kit_6551.aspx

Schluter has been in the tile industry a long time.



On 11/1/2015 1:59 PM, wrote:
On Sun, 1 Nov 2015 16:41:03 -0000 (UTC), HerHusband
wrote:

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

I used Hardibacker for our showers. It's thinner and easier to cut.

The backerboard is a minimal cost compared to the rest of a tiling project.

Do it once, do it right.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com
Do it once, do it right. Use Kerdi (Shluter system)
Either standard Kerdi over whatever wallboard you want to use, or
KerdiBoard. You don't need soncrete backer with Kerdi, and you use
thinset - it is totally waterproof and pretty well goofproof. It is
not particularly cheap, but good seldom is. It has a handy "grid" for
helping to keep the tile-job square. They also have KerdiDrain for the
bottom of the shower (pan) to use with Ditra to make a waterproof
shower pan.

On 11/1/2015 5:19 AM, Mayayana wrote:
| I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
| In other places, I've thought that the expense of Durock wasn't worth
| it, but I'm leaning toward recommending it for this job.
|

I wouldn't tile on drywall even in a dry room.
It's just stuck to paper. In the 80s, before
concrete board and after metal lath was common,
most tiling was either on plywood or drywall. The
former would pop off due to expansion/contraction,
while the latter had a short life expectancy - often
less than 10 years, depending on how carefully one
caulked to keep water out of the wall.

I only tile on concrete board with thinset. It's
more work than using tile mastic and/or drywall,
but the result is a mortar wall that will last.

Side note: I've noticed that greenboard is no
longer grayish inside, and sometimes comes as
"purpleboard". I'm curious whether anyone knows
the story there. I thought greenboard probably
had tar to make it water-resistant, and that maybe
that was banned, but I don't know.





Thx for your comment, Maya, I didn't read closely enough. Do you plywood
behind joints (between studs) as backer?

Can we use ordinary drywall mesh for the seam?

--
Cal

I used Hardibacker for our showers. It's thinner and easier to cut.

The backerboard is a minimal cost compared to the rest of a tiling
project.

Do it once, do it right.

Do it once, do it right. Use Kerdi (Shluter system)
Either standard Kerdi over whatever wallboard you want to use, or
KerdiBoard. You don't need soncrete backer with Kerdi, and you use
thinset - it is totally waterproof and pretty well goofproof. It is
not particularly cheap, but good seldom is. It has a handy "grid" for
helping to keep the tile-job square. They also have KerdiDrain for the
bottom of the shower (pan) to use with Ditra to make a waterproof
shower pan.

Agreed! We used the standard Kerdi for our showers:

http://www.johnbridge.com/vbulletin/...ad.php?t=12876

I had not heard of Kerdiboard. It looks interesting but wasn't available
when we built out house in 2003.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com

Do you plywood behind joints (between studs) as backer?

Hardibacker comes in 3'x5' sheets (Durock can be bought in 4'x8' sheets).
In most showers a single sheet will span wall to wall so you shouldn't have
any seams. However, if you need to have a joint cut the sheets as needed so
the seam ends up over a stud.

Adding blocking behind horizontal seams would add a little extra strength,
but it is not a necessity if you tape and mortar the joints (similar to
taping drywall joints).

Can we use ordinary drywall mesh for the seam?

I used the mesh specifically sold for taping backerboard seams, but I don't
think there's any real difference from the regular fiberglass tape used
with drywall. Still, a roll is only $4 so it seems pointless to guess on
something so inexpensive.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com

wrote:
On Sun, 1 Nov 2015 16:41:03 -0000 (UTC), HerHusband
wrote:

I'm tiling a very small quarter bath (shower) in the wet part of Oregon.
In other places, I've thought that the expense of Durock wasn't worth
it, but I'm leaning toward recommending it for this job.

I used Hardibacker for our showers. It's thinner and easier to cut.

The backerboard is a minimal cost compared to the rest of a tiling project.

Do it once, do it right.

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com
Do it once, do it right. Use Kerdi (Shluter system)
Either standard Kerdi over whatever wallboard you want to use, or
KerdiBoard. You don't need soncrete backer with Kerdi, and you use
thinset - it is totally waterproof and pretty well goofproof. It is
not particularly cheap, but good seldom is. It has a handy "grid" for
helping to keep the tile-job square. They also have KerdiDrain for the
bottom of the shower (pan) to use with Ditra to make a waterproof
shower pan.

I have the Kerdi drain in anticipation of finishing my shower.

Greg

| Thx for your comment, Maya, I didn't read closely enough. Do you plywood
| behind joints (between studs) as backer?
|

I usually just try to
leave such joints high up. As Anthony said, it
come 1/2"x3'x5'. (I've never seen 4x8 where I am.)
So it's basically one sheet on each end and
two in the middle. The joint where they meet
should be a stud.

Staple plastic on the studs first and cut it
at the bottom after boarding. If you then caulk
that joint before tiling you'll have 2 caulk joints
at the end to keep water out of the wall.
(The concrete board companies at least used
to recommend no plastic, in order to let it air
out behind if it gets wet. That doesn't make
sense to me. First, it shouldn't get wet. Second, if
it ever does the concrete board can tolerate
being damp for far longer than the studs can.)

I had one job where the customer apparently
fell against the wall and a crack in the tile resulted.
I assumed it must have been on a joint and
offered to replace that tile. It turned out not
to be on a joint. It was in the middle of the board.
As far as I could tell, the cause seemed to be
a combination of flex in the concrete board and
cheap tile that was soft. I don't actually know,
though, what they did to cause the cracks. But
the moral of that story for me is to avoid large
spans. Some horizontal blocking is not a bad idea
if that's practical.

Personally I don't trust hardibacker, but
I've never actually used it. I'm just wary of
a composite product. Like using chipboard for
house sheathing. It's legal. It seems to work.
But what if the glue breaks down in 20 years?
30 years? 40 years? Or even 10 years. There's
a lot of technology out there that hasn't been
around long enough to be time-tested.

| Can we use ordinary drywall mesh for the seam?
|
I'd double it if you do that. The concrete board
mesh tape is stronger, though.

Mayayana wrote:
Staple plastic on the studs first and cut it
at the bottom after boarding. If you then caulk
that joint before tiling you'll have 2 caulk joints
at the end to keep water out of the wall.
(The concrete board companies at least used
to recommend no plastic, in order to let it air
out behind if it gets wet. That doesn't make
sense to me. First, it shouldn't get wet. Second, if
it ever does the concrete board can tolerate
being damp for far longer than the studs can.)

If you use the plastic, it will trap the small amount of moisture that WILL go
through the grout, resulting in possible mildew problems. Better to use a few
coats of Redgard or a similar product on the concrete board before tiling.
Without any coating, moisture can evaporate after going through the backerboard
so that moisture does not build up to cause problems.

| If you use the plastic, it will trap the small amount of moisture that
WILL go
| through the grout, resulting in possible mildew problems. Better to use a
few
| coats of Redgard or a similar product on the concrete board before tiling.
| Without any coating, moisture can evaporate after going through the
backerboard
| so that moisture does not build up to cause problems.
|

That's the theory, but it doesn't make sense
to me. Moisture can migrate through the top if
it gets through. But if there's a break, and lack
of plastic is letting moisture reach a stud, then
eventually the whole thing will have to be redone.
I've always used plastic and never had a problem.

I just looked up Redgard. Personally
I'd be very dubious about such a product.
You'll end up not with a mortar wall but
with tile stuck to a plastic coating, that's
in turn stuck to the concrete board. Will
that hold up? Who knows? Another product
that's not necessary and not time-tested.

Also, if you waterproof the concrete board
you haven't done anything to stop water
getting through. Leaks won't happen in the
middle of the sheet. They'll happen at the
bottom, corners, or around fixtures. In those
areas a coating on the concrete board won't
help.

On 11/02/2015 06:30 AM, Mayayana wrote:
| If you use the plastic, it will trap the small amount of moisture that
WILL go
| through the grout, resulting in possible mildew problems. Better to use a
few
| coats of Redgard or a similar product on the concrete board before tiling.
| Without any coating, moisture can evaporate after going through the
backerboard
| so that moisture does not build up to cause problems.
|

That's the theory, but it doesn't make sense
to me. Moisture can migrate through the top if
it gets through. But if there's a break, and lack
of plastic is letting moisture reach a stud, then
eventually the whole thing will have to be redone.
I've always used plastic and never had a problem.

The idea is that you only want one moisture barrier, and with so many
houses now using housewrap, if you put plastic on the studs you are
creating an area in which any trapped moisture has no where to go. As
the dewpoint changes, this trapped moisture will, at times, condense,
leading to mold problems.

In my shower I just put the hardibacker right on the studs, then
slathered it with redgard before I began tiling (using thinset mortar,
of course).

Jon

| The idea is that you only want one moisture barrier, and with so many
| houses now using housewrap, if you put plastic on the studs you are
| creating an area in which any trapped moisture has no where to go. As
| the dewpoint changes, this trapped moisture will, at times, condense,
| leading to mold problems.
|

That's not actually how it works. The housewrap
should be a wind barrier that allows moisture to
migrate through.

"The TYPAR Weather Protection System. It provides
exceptional air and water holdout, optimal moisture
vapor transmission"

(I wouldn't trust housewrap to stop liquid water,
but that's another debate.

The inside walls can then be
covered in plastic as a moisture barrier. So moisture
is never getting into the walls from the inside in the
first place. That's also a nice bonus where winters
result in very dry indoor air.

Though in most of the places I work houses are
not wrapped. They may have tar paper, but the
walls are usually leaky in terms of air flow. Old houses
are not wrapped unless they're wood and have
been completely redone on the outside, with all
the old siding stripped off. Where I live that's not
at all common. In fact, I'm often dealing with houses
that have incomplete or no insulation.

| In my shower I just put the hardibacker right on the studs, then
| slathered it with redgard before I began tiling (using thinset mortar,
| of course).
|

I'd consider that an unnecessary experiment.
Hopefully it works out OK. But your thinset
is now not bonded to the hardibacker. It's
bonded to the Redgard plastic coating. You've
lost the advantage of producing a composite
mortar wall. With concrete board, thinset and tile
you'd end up with essentially a single mortar panel.

We've discussed this issue before. People have
different opinions. To my mind there are an awfully
lot of new inventions that are not time-tested and
for which there's really no standards system to
decide whether they actually make sense. I'd
consider hardibacker, Redgard and waffle sheet
underlayment all to be in that category -- claiming
to solve a non-existent problem. Though I would
be interested if someone came up with an easier-
to-use version of concrete board that's also stronger.
It's too easy to cause cracks in the concrete filler
by bending and hitting.

On Mon, 2 Nov 2015 09:30:20 -0500, "Mayayana"
wrote:

| If you use the plastic, it will trap the small amount of moisture that
WILL go
| through the grout, resulting in possible mildew problems. Better to use a
few
| coats of Redgard or a similar product on the concrete board before tiling.
| Without any coating, moisture can evaporate after going through the
backerboard
| so that moisture does not build up to cause problems.
|

That's the theory, but it doesn't make sense
to me. Moisture can migrate through the top if
it gets through. But if there's a break, and lack
of plastic is letting moisture reach a stud, then
eventually the whole thing will have to be redone.
I've always used plastic and never had a problem.

Just use the shluter system and be done with it. 100% water and
moisture proof. No second guessing.

On Mon, 02 Nov 2015 07:00:02 -0800, Jon Danniken
wrote:

On 11/02/2015 06:30 AM, Mayayana wrote:
| If you use the plastic, it will trap the small amount of moisture that
WILL go
| through the grout, resulting in possible mildew problems. Better to use a
few
| coats of Redgard or a similar product on the concrete board before tiling.
| Without any coating, moisture can evaporate after going through the
backerboard
| so that moisture does not build up to cause problems.
|

That's the theory, but it doesn't make sense
to me. Moisture can migrate through the top if
it gets through. But if there's a break, and lack
of plastic is letting moisture reach a stud, then
eventually the whole thing will have to be redone.
I've always used plastic and never had a problem.

The idea is that you only want one moisture barrier, and with so many
houses now using housewrap, if you put plastic on the studs you are
creating an area in which any trapped moisture has no where to go. As
the dewpoint changes, this trapped moisture will, at times, condense,
leading to mold problems.

Except housewrap is water repellant and not moisture proof. It is
designed to breathe and pass moisture freely.

In my shower I just put the hardibacker right on the studs, then
slathered it with redgard before I began tiling (using thinset mortar,
of course).

Jon

| Just use the shluter system and be done with it. 100% water and
| moisture proof. No second guessing.

I'm about convinced that you have stock in
that company. I see no reason or even
logic for it, other than to make lots of money
selling the allure of "cutting edge technology".

Mayayana wrote:
I just looked up Redgard. Personally
I'd be very dubious about such a product.
You'll end up not with a mortar wall but
with tile stuck to a plastic coating, that's
in turn stuck to the concrete board. Will
that hold up? Who knows? Another product
that's not necessary and not time-tested.

Also, if you waterproof the concrete board
you haven't done anything to stop water
getting through. Leaks won't happen in the
middle of the sheet. They'll happen at the
bottom, corners, or around fixtures. In those
areas a coating on the concrete board won't
help.

The coating is over the board, board tape, and thinset applied at those
locations. Thge redgard keeps any moisture that gets through the grout from
getting through the concrete board. Then it either has to find its way back out
through the grout, or find a path, hopefully back into the tub area, through the
caulk at the bottom of the tile.

The plastic you suggest would likely create a problem with condensation into the
wall/floor space below the plastic, or the same potential water issue at the
caulking at the bottom of the tile.

| The coating is over the board, board tape, and thinset applied at those
| locations.

Yes, I understand that, which is why I said
you're losing the mortar integrity. You're
gluing your tile to a plastic coating rather
than getting a thinset - concrete bond.

| The redgard keeps any moisture that gets through the grout from
| getting through the concrete board. Then it either has to find its way
back out
| through the grout, or find a path, hopefully back into the tub area,
through the
| caulk at the bottom of the tile.
|

That sounds like Redgard marketing hocus pocus
to me. Tiling on mortar has been done for thousands
of years. Why, all of a sudden, is grout considered
to be a non-waterproof material? Even if tiny bits
of moisture can go through some grout, the concrete
board is designed to let it migrate out. The top of
the concrete board is not plastic wrapped.

I've been doing the same for years and never had
a problem. I also built a steam room about 12-15
years ago. It's been heavily used with no sign of
problems. Just as nearly every other steam room
ever built has been some version of tile on mortar
and has worked just fine. If moisture were getting
through then even steam rooms built with concrete
wall on metal lath would eventually break down.

The Shluter system is, in theory, similar to the
Redgard approach, except that it would provide
full waterproofing where Redgard probably won't.
But it's also similar in that it's a plastic sheet glued
to the wall. So the tile is only as stong as the bond
between the thinset and that plastic sheet. The
Shluter people even show their sheet being used
over drywall! In that case the bond depends on
tile - plastic and also plastic - paper. That
seems idiotic to me. And why do they claim it
makes sense? Just to keep the moisture barrier on
the front side of the wall, with the theory that
otherwise the concrete board will somehow get wet
due to water leaking through the grout. The reasoning
just doesn't hold water, so to speak.

| The plastic you suggest would likely create a problem with condensation
into the
| wall/floor space below the plastic, or the same potential water issue at
the
| caulking at the bottom of the tile.
|

No, because the plastic is sealing it out. The
plastic comes down behind the concrete board
and the gap gets caulked before tiling. It's
always possible that water can get through --
at the top of a porrly caulked tub or around
a poorly sealed mixing valve, for instance. But
in general a plastic sheet is going to provide
a good seal.

posted for all of us...



On Mon, 2 Nov 2015 09:30:20 -0500, "Mayayana"
wrote:

| If you use the plastic, it will trap the small amount of moisture that
WILL go
| through the grout, resulting in possible mildew problems. Better to use a
few
| coats of Redgard or a similar product on the concrete board before tiling.
| Without any coating, moisture can evaporate after going through the
backerboard
| so that moisture does not build up to cause problems.
|

That's the theory, but it doesn't make sense
to me. Moisture can migrate through the top if
it gets through. But if there's a break, and lack
of plastic is letting moisture reach a stud, then
eventually the whole thing will have to be redone.
I've always used plastic and never had a problem.

Just use the shluter system and be done with it. 100% water and
moisture proof. No second guessing.

+1

--
Tekkie

Mayayana posted for all of us...



| Just use the shluter system and be done with it. 100% water and
| moisture proof. No second guessing.

I'm about convinced that you have stock in
that company. I see no reason or even
logic for it, other than to make lots of money
selling the allure of "cutting edge technology".

-1 He resoning is: because it works.

--
Tekkie

On Mon, 2 Nov 2015 12:48:11 -0500, "Mayayana"
wrote:

| Just use the shluter system and be done with it. 100% water and
| moisture proof. No second guessing.

I'm about convinced that you have stock in
that company. I see no reason or even
logic for it, other than to make lots of money
selling the allure of "cutting edge technology".

No stock in the company, and this "cutting edge technology" is about
30 years old.

It works
Period. It is a small part of the cost when you consider the labour
and everything - and it GUARANTEES you don't need to redo it in 5
years because you guessed wrong and used the wrong stuff trying to
save $50.

On Mon, 2 Nov 2015 14:53:39 -0500, "Mayayana"
wrote:

| The coating is over the board, board tape, and thinset applied at those
| locations.

Yes, I understand that, which is why I said
you're losing the mortar integrity. You're
gluing your tile to a plastic coating rather
than getting a thinset - concrete bond.

| The redgard keeps any moisture that gets through the grout from
| getting through the concrete board. Then it either has to find its way
back out
| through the grout, or find a path, hopefully back into the tub area,
through the
| caulk at the bottom of the tile.
|

That sounds like Redgard marketing hocus pocus
to me. Tiling on mortar has been done for thousands
of years. Why, all of a sudden, is grout considered
to be a non-waterproof material? Even if tiny bits
of moisture can go through some grout, the concrete
board is designed to let it migrate out. The top of
the concrete board is not plastic wrapped.

Grout has ALWAYS been considered a non-watertite material.

I've been doing the same for years and never had
a problem. I also built a steam room about 12-15
years ago. It's been heavily used with no sign of
problems. Just as nearly every other steam room
ever built has been some version of tile on mortar
and has worked just fine. If moisture were getting
through then even steam rooms built with concrete
wall on metal lath would eventually break down.

The Shluter system is, in theory, similar to the
Redgard approach, except that it would provide
full waterproofing where Redgard probably won't.
But it's also similar in that it's a plastic sheet glued
to the wall. So the tile is only as stong as the bond
between the thinset and that plastic sheet. The
Shluter people even show their sheet being used
over drywall! In that case the bond depends on
tile - plastic and also plastic - paper. That
seems idiotic to me. And why do they claim it
makes sense? Just to keep the moisture barrier on
the front side of the wall, with the theory that
otherwise the concrete board will somehow get wet
due to water leaking through the grout. The reasoning
just doesn't hold water, so to speak.

| The plastic you suggest would likely create a problem with condensation
into the
| wall/floor space below the plastic, or the same potential water issue at
the
| caulking at the bottom of the tile.
|

No, because the plastic is sealing it out. The
plastic comes down behind the concrete board
and the gap gets caulked before tiling. It's
always possible that water can get through --
at the top of a porrly caulked tub or around
a poorly sealed mixing valve, for instance. But
in general a plastic sheet is going to provide
a good seal.

It's your job and your choice. You will do it your way regardless.
If it works for you, that's all that counts.
I'm just saying if someone who has not done it many times your way
wants to do the job and be SURE the job is done right, Shluter is his
best friend.

On 11/2/2015 9:17 AM, Bob F wrote:


If you use the plastic, it will trap the small amount of moisture that WILL go
through the grout, resulting in possible mildew problems.

Epoxy or urethane grout greatly reduces that possibility too.

Ed Pawlowski wrote:
On 11/2/2015 9:17 AM, Bob F wrote:


If you use the plastic, it will trap the small amount of moisture
that WILL go through the grout, resulting in possible mildew
problems.

Epoxy or urethane grout greatly reduces that possibility too.

No doubt.

On 11/2/2015 12:48 PM, Mayayana wrote:
| Just use the shluter system and be done with it. 100% water and
| moisture proof. No second guessing.

I'm about convinced that you have stock in
that company. I see no reason or even
logic for it, other than to make lots of money
selling the allure of "cutting edge technology".



It works, a very important part of the job. We opted to use Swanstone
bases rather than tile on the base, but if not, Schluter would have been
used.

Mayayana wrote:
The coating is over the board, board tape, and thinset applied at
those locations.

Yes, I understand that, which is why I said
you're losing the mortar integrity. You're
gluing your tile to a plastic coating rather
than getting a thinset - concrete bond.

The redgard keeps any moisture that gets through the grout from
getting through the concrete board. Then it either has to find its
way back out through the grout, or find a path, hopefully back into
the tub area, through the caulk at the bottom of the tile.


That sounds like Redgard marketing hocus pocus
to me. Tiling on mortar has been done for thousands
of years. Why, all of a sudden, is grout considered
to be a non-waterproof material? Even if tiny bits
of moisture can go through some grout, the concrete
board is designed to let it migrate out. The top of
the concrete board is not plastic wrapped.

I've been doing the same for years and never had
a problem. I also built a steam room about 12-15
years ago. It's been heavily used with no sign of
problems. Just as nearly every other steam room
ever built has been some version of tile on mortar
and has worked just fine. If moisture were getting
through then even steam rooms built with concrete
wall on metal lath would eventually break down.

The Shluter system is, in theory, similar to the
Redgard approach, except that it would provide
full waterproofing where Redgard probably won't.
But it's also similar in that it's a plastic sheet glued
to the wall. So the tile is only as stong as the bond
between the thinset and that plastic sheet. The
Shluter people even show their sheet being used
over drywall! In that case the bond depends on
tile - plastic and also plastic - paper. That
seems idiotic to me. And why do they claim it
makes sense? Just to keep the moisture barrier on
the front side of the wall, with the theory that
otherwise the concrete board will somehow get wet
due to water leaking through the grout. The reasoning
just doesn't hold water, so to speak.

The plastic you suggest would likely create a problem with
condensation into the wall/floor space below the plastic, or the
same potential water issue at the caulking at the bottom of the tile.


No, because the plastic is sealing it out. The
plastic comes down behind the concrete board
and the gap gets caulked before tiling. It's
always possible that water can get through --
at the top of a porrly caulked tub or around
a poorly sealed mixing valve, for instance. But
in general a plastic sheet is going to provide
a good seal.

You could use plastic or tarpaper just a few inches wide on the studs to keep
them dry and still allow the cement board to breath.