# Kerdi Board



## txgencon (Jan 4, 2011)

Is this product fairly new? I have only heard about it recently. Has anyone used it? Results? Opinions?


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## Golden view (Feb 16, 2012)

I use it and like it. Featherweight, cuts with a razor. Install and begin tiling same day.


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## tjbnwi (Feb 24, 2009)

Used it since it hit the market 5 years ago. 

Tom


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## Tom M (Jan 3, 2007)

I have a question too.
Whats the deal with grab bars? Are you screwed without blocking? 

I saw Wedi uses a silicone to cover joints and screws. In this months magazine I saw the writer chose kerdi band and thinset for fasteners and joints? Seems like a lot more work and would make the wall lumpy. Any preference?


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## TNTRenovate (Aug 19, 2010)

Tom M said:


> I have a question too.
> Whats the deal with grab bars? Are you screwed without blocking?
> 
> I saw Wedi uses a silicone to cover joints and screws. In this months magazine I saw the writer chose kerdi band and thinset for fasteners and joints? Seems like a lot more work and would make the wall lumpy. Any preference?


You have to attached grab bars to structure regardless of your substrate choice.

Kerdi Band is to waterproof the seams and fastners. It's made from Kerdi Membrane with is an amazing product. If you take the class they will show you the water retention properties even without thinset boding the layers. You can take a square piece of it and cut a slit to the middle. Shape it into a cone and then pour water in it. It will not leak.

The band and membrane do raise the plane at those points, but why would that affect your installation? Even if you only troweled the wall or tile the thinset would contour to the slight hump and should affect your installation. Anytime that I can I am using a leveling system which would eliminate any worry of that telegraphing through to the tile.


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## Xtrememtnbiker (Jun 9, 2013)

Since we started with it sometime early in 2015 (I think) we haven't used anything since.

It's light, cuts easy, installs fast, etc.


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## Tom M (Jan 3, 2007)

Xtrememtnbiker said:


> Since we started with it sometime early in 2015 (I think) we haven't used anything since.
> 
> It's light, cuts easy, installs fast, etc.


And what's your joint preference?


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## DaVinciRemodel (Oct 7, 2009)

Tom M said:


> I have a question too.
> Whats the deal with grab bars? Are you screwed without blocking?


http://www.wingits.com/products.php?id=2


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## Golden view (Feb 16, 2012)

It doesn't take that long to apply the band to fasteners and it's pretty thin stuff.


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## Xtrememtnbiker (Jun 9, 2013)

Tom M said:


> And what's your joint preference?


I use Schluter's instructions which are Kerdi band which is 1/2 (?) the thickness of Kerdi. Same for patching over the screws. I'm a great deal faster at it than I was the first shower or two.

If the thinset is the proper consistency for Kerdi, there is minimal build up and I have yet to have trouble with it. Like Rob, I use a tile lippage system, the RLS.


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## Tom M (Jan 3, 2007)

DaVinciRemodel said:


> http://www.wingits.com/products.php?id=2


I know, I have used those and similar...... Thus it s foam


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## Xtrememtnbiker (Jun 9, 2013)

Tom M said:


> I know, I have used those and similar...... Thus it s foam


Kerdi board is very strong compared to 1/2" XPS foam.

That being said, I'm not sure what Schluter would say about grab bars using the wingit's. I'd just call them or ask another guy on here his opinion.


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## txgencon (Jan 4, 2011)

I don't think I would use it directly over studs. I've only used the membrane system twice and both times it was over 23/32" T&G OSB and then 1/2" cement board (Durock). If I used Kerdi board, I would probably elect to install it over 23/32" T&G OSB. 

My layering technique requires furring out the walls adjacent to the shower but I like the structure to be really solid in the shower area.


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## Xtrememtnbiker (Jun 9, 2013)

txgencon said:


> I don't think I would use it directly over studs. I've only used the membrane system twice and both times it was over 23/32" T&G OSB and then 1/2" cement board (Durock). If I used Kerdi board, I would probably elect to install it over 23/32" T&G OSB.
> 
> My layering technique requires furring out the walls adjacent to the shower but I like the structure to be really solid in the shower area.


What the heck is happening in your shower's...??

I have no issues with Kerdi board directly to studs and installing tile over top. Why go to all the extra trouble?


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## Tom M (Jan 3, 2007)

Think I was quoted $54. for a 3x5 board. Maybe $125 for 4x8. I have a couple of baths in the fire, I estimated for these. We will see


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## txgencon (Jan 4, 2011)

Xtrememtnbiker said:


> What the heck is happening in your shower's...??
> 
> I have no issues with Kerdi board directly to studs and installing tile over top. Why go to all the extra trouble?


Years ago I built a house for a young couple. The shower in the master bath was 60 x 54 and was simply wall tile over MR drywall (which was the norm at the time). Not long after the couple moved, tiles started coming loose. I called my tile guy to repair and he brought it to my attention that the drywall was bowed in between studs and was actually broken (pushed in) in a couple of places 4'-5' from the floor. We learned from the homeowners that was where the woman put her hands to support herself .....

My current practice is in response to that situation.


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## CarpenterSFO (Dec 12, 2012)

It does come in different thicknesses. The thicker ones are quite stiff, but there's no harm in putting up CB or the like, then 1/2" kerdi board for waterproofing and flatness. The thin ones are great for assembling complicated murals or mosaics - do them on a bench in the shop, then put the whole thing up on the wall.


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## Golden view (Feb 16, 2012)

Tom M said:


> Think I was quoted $54. for a 3x5 board. Maybe $125 for 4x8. I have a couple of baths in the fire, I estimated for these. We will see


You should be able to do better than that.


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## Golden view (Feb 16, 2012)

txgencon said:


> Years ago I built a house for a young couple. The shower in the master bath was 60 x 54 and was simply wall tile over MR drywall (which was the norm at the time). Not long after the couple moved, tiles started coming loose. I called my tile guy to repair and he brought it to my attention that the drywall was bowed in between studs and was actually broken (pushed in) in a couple of places 4'-5' from the floor. We learned from the homeowners that was where the woman put her hands to support herself .....
> 
> My current practice is in response to that situation.


The 1" stuff would probably handle a couple of 300lb newlyweds and save you a step.


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## TNTRenovate (Aug 19, 2010)

txgencon said:


> Years ago I built a house for a young couple. The shower in the master bath was 60 x 54 and was simply wall tile over MR drywall (which was the norm at the time). Not long after the couple moved, tiles started coming loose. I called my tile guy to repair and he brought it to my attention that the drywall was bowed in between studs and was actually broken (pushed in) in a couple of places 4'-5' from the floor. We learned from the homeowners that was where the woman put her hands to support herself .....
> 
> My current practice is in response to that situation.


Kerdi Board isn't just a substrate, but a structural foam board. You can build benches and knee walls with the stuff. No need to reinforce it.


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## overanalyze (Dec 28, 2010)

It was a little tougher to cut than I thought but still easy enough with a sharp knife blade. Then it snaps pretty clean. 

The surface is some sort of fiberglass and coating. Water just beads up on it. 

I made this and will fill it with water once the caulk dries. I will mark the water level and let it sit overnight. 

I really like how a regular durock screw sets. When using densshield it always pickers around the screws. 

The core is pretty dense foam. It looks identical to the core in Johns Mansville insulated sheeting...which makes sense.


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## overanalyze (Dec 28, 2010)

...Double post


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## Tom M (Jan 3, 2007)

So how do the fasteners and washers affect these foam core boards? Does the face shell crack ?


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## tjbnwi (Feb 24, 2009)

Tom M said:


> So how do the fasteners and washers affect these foam core boards? Does the face shell crack ?


The face does not crack, they do compress the core (on Kerdi board).

Tom


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## Tom M (Jan 3, 2007)

I called around yesterday and called a couple of manufacturers to find a local distributor. Far and few carry it and the prices are up there.


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## overanalyze (Dec 28, 2010)

So assuming my little Flood test pans out...any reason not to use/try this? I am still going to use the Kerdi drain and pan...??


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## CPMKW (Apr 28, 2014)

Wondering how you would tie the Kerdi and goboard. Use Kerdi band? 

Seems most similar to wedi. Not sure why it doesn't call for the washer and screw that wedi and Kerdi both use.


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## overanalyze (Dec 28, 2010)

CPMKW said:


> Wondering how you would tie the Kerdi and goboard. Use Kerdi band?
> 
> Seems most similar to wedi. Not sure why it doesn't call for the washer and screw that wedi and Kerdi both use.


Yeah I would transition between the pan and wall with Kerdi band. 

Not sure why they don't spec a washer screw. I screwed a piece to a 2x today using cement board screws at their recommended spacing and it was a very solid connection.


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## overanalyze (Dec 28, 2010)

So overnight I didn't lose any water. Zero signs of moisture underneath. Also withheld my weight standing on it. Also held my partner and he has an extra 50 plus lbs over me.


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## Tom M (Jan 3, 2007)

That looks impressive, successful test.


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## CPMKW (Apr 28, 2014)

overanalyze said:


> So overnight I didn't lose any water. Zero signs of moisture underneath. Also withheld my weight standing on it. Also held my partner and he has an extra 50 plus lbs over me.


What caulking did you use? Sikaflex?


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## overanalyze (Dec 28, 2010)

CPMKW said:


> What caulking did you use? Sikaflex?


Actually TiteBond WeatherMaster...it was what I had on hand.


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## overanalyze (Dec 28, 2010)

Well since I officially hijacked this thread I am going to use this GoBoard on my next shower. None of my tests failed and I can't see why I shouldn't. I will start a new topic when I do. Starting it next week.


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## MarcoPollo (Dec 6, 2014)

My vote is for WEDI over Kerdi. One thing I like about the WEDI is the caulking can easily be discarded and smeared if you have extra while I know discussion over cleanup of thinset in houses can sometimes be time consuming and challenging. Also adds weight for disposal of dumps and ours charge based on weight. 

Secondly I like how with WEDI you can use Modified mortar and maintain the warranty with the entire system which makes any mosaic or glass install easier as you save a step (schluter asks for a skim of unmodified before using modified to keep warranty). Means that I don't get caught with multiple different bags of mortar all the time.

These are not huge differences but I find the install simpler and straight forward without confusing rules that schluter requires for warranty. Some food for thought.

Finally, be careful with polyisocyanurate foam boards. I have been told from some guys that they can break down over time when exposed to weather up north here, which makes me nervous for that type of a board in this application.


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## TaylorMadeAB (Nov 11, 2014)

MarcoPollo said:


> My vote is for WEDI over Kerdi. One thing I like about the WEDI is the caulking can easily be discarded and smeared if you have extra while I know discussion over cleanup of thinset in houses can sometimes be time consuming and challenging. Also adds weight for disposal of dumps and ours charge based on weight.
> 
> Secondly I like how with WEDI you can use Modified mortar and maintain the warranty with the entire system which makes any mosaic or glass install easier as you save a step (schluter asks for a skim of unmodified before using modified to keep warranty). Means that I don't get caught with multiple different bags of mortar all the time.
> 
> ...



I used WEDI on a shower last year, and was quite happy with it. My only complaints would be the cost of the shower pans was almost double of a Schulter pan, and the sizes were pretty limited as well.


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## tjbnwi (Feb 24, 2009)

MarcoPollo said:


> My vote is for WEDI over Kerdi. One thing I like about the WEDI is the caulking can easily be discarded and smeared if you have extra while I know discussion over cleanup of thinset in houses can sometimes be time consuming and challenging. Also adds weight for disposal of dumps and ours charge based on weight.
> 
> Secondly I like how with WEDI you can use Modified mortar and maintain the warranty with the entire system which makes any mosaic or glass install easier as you save a step (schluter asks for a skim of unmodified before using modified to keep warranty). Means that I don't get caught with multiple different bags of mortar all the time.
> 
> ...


I've never heard the skim with un-modified then use modified before. I know Schluter will warranty the entire system when you use their system.

I have also used Wedi. 

Tom


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## MarcoPollo (Dec 6, 2014)

To be clear this was over Kerdi mat/band as part of install methods. Could be different with their board?


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## MarcoPollo (Dec 6, 2014)

http://www.schluter.com/schluter-us...er®-KERDI-BOARD/p/KERDI_BOARD#tabInstallation

On installation unmodified required. Therefore a skim would be required prior to bonding glass or anything requiring modified by tile manufacturer? Unless I'm misunderstanding?


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## tjbnwi (Feb 24, 2009)

MarcoPollo said:


> http://www.schluter.com/schluter-us...er®-KERDI-BOARD/p/KERDI_BOARD#tabInstallation
> 
> On installation unmodified required. Therefore a skim would be required prior to bonding glass or anything requiring modified by tile manufacturer? Unless I'm misunderstanding?


I know unmodified is required. It was your skim coat I was questioning.

Schluter states to use unmodified only, if the manufacture requires (such as porcelain or glass) they (Schluter) will cover the install 100% no matter what the tile manufacture requires. 

I saw one install Schluter covered, honestly they should not have. Every issue was installer stupidity, not only in the Schluter but everything else on the job. 

Tom


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## country_huck (Dec 2, 2009)

tjbnwi said:


> MarcoPollo said:
> 
> 
> > http://www.schluter.com/schluter-us...er®-KERDI-BOARD/p/KERDI_BOARD#tabInstallation
> ...


It's the same with Ditra XL, they will warrant any cracking on a single layer of 3/4 plywood on 24" centers. Even though the TCNA guidelines as well as many associated manufactures say hell no.


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## TNTRenovate (Aug 19, 2010)

Golden view said:


> The premade niches are worth the money...


dupe...


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## Golden view (Feb 16, 2012)

TNTSERVICES said:


> So small. I think I am going to start making my own with Kerdi board and Kerdi fix.


The unfinished niche in the pic above looked abut the size of the larger premade one which is why I mentioned it. But they are easy to make with how nice the board scores and bends.


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## TaylorMadeAB (Nov 11, 2014)

TNTSERVICES said:


> So small. I think I am going to start making my own with Kerdi board and Kerdi fix.



I can't understand why they don't make bigger ones. Ever the larger size isn't really any better with that half shelf in the middle. Plus that would be a pain to tile around.


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## Golden view (Feb 16, 2012)

TaylorMadeCon said:


> I can't understand why they don't make bigger ones. Ever the larger size isn't really any better with that half shelf in the middle. Plus that would be a pain to tile around.


The shelf is not attached. It's optional and you can put it anywhere you want.


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## Golden view (Feb 16, 2012)

12x20 and 12x28 are available


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## tjbnwi (Feb 24, 2009)

gbruzze1 said:


> Hung kerdi board in my two bathrooms this weekend. So easy to install. Just waiting on the plumber to install the shower bodies to finish up. Also waiting for tapers to finish before I install the kerdi pan and finish installing bottom board in the shower.
> 
> Around the niche, can I cover the 2x4 sides and plywood back in kerdi band and tile right over that, or should I install kerdi board in the niche?


Use Kerdi board, you already have the back from the face sheet, use the window cutout to fab the sides. As mentioned, Kerdi Fix it together.

You can wait to do the niche until you start laying up the tile, that way if you missed your layout you can adjust the niche size.

Tom


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## Philament (Dec 9, 2014)

Xtrememtnbiker said:


> That's what I do. I've been using pink XPS foam for it with Kerdi fix and Aqua D because that's what Angus did and so I bought some. It's an awesome way of doing a niche where you do it as the last step and so it's dead on with the tile layout.
> 
> After building your own niche that fits spot on with your layout it's hard to use a pre fab.


Can you elaborate on this, or point me to the thread where this was explained?


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## Xtrememtnbiker (Jun 9, 2013)

Philament said:


> Can you elaborate on this, or point me to the thread where this was explained?


Check out post #3,317 for a picture of what the finished niche looks like.

http://www.contractortalk.com/f73/what-tile-project-you-working-79809/index166/

I don't have any progress photo's posted yet and can't take the time to find them right now.

The short version is on this particular shower I knew exactly where I wanted the niche and I framed for it prior to installing the substrate.

I marked "niche" on the substrate so I wouldn't forget it and tiled the whole shower. When I got to the niche, I set a tile with no thinset there for spacing to make the niche exactly the size of a tile so no cuts where needed.

Remove the tile, take a drywall saw and cut the substrate out. Then I used 2" foam for the bottom (I'm sure 1 1/2" would also work) and 1/2" for the sides, top, and back. I'm just assembling in the wall using Kerdi fix as the glue and then brushing Aqua defense over top for waterproofing. Then you tile the niche and you have a niche that fits perfect in your layout.

I'll do a new thread later with pictures once I find them.


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## Tom M (Jan 3, 2007)

How are you guys treating the the foam edges. In a case where you have a fiberglass pan you will have a bottom edge or more important in the case where you have an alcove stall or tub you may outside corners. I know kerdi band or fleece with thinset is a popular method.
I think I would consider mitering my boards to maintain the surface.

Unfortunately, after finally hunting down a couple of places to buy the stuff sticker has scared off the baths I quoted. Very hard to contract bath work as a GC unless your tiling in house.


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## gbruzze1 (Dec 17, 2008)

I plan on wrapping all corners, inside and out, in kerdi band. Will also use a kerdi outside corner at the bottom of the window and niche. 

It is expensive, but I really think it's not as expensive as more traditional methods, unless you're omitting waterproofing entirely. 


Sent from my iPad using Tapatalk


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## tjbnwi (Feb 24, 2009)

Tom M said:


> How are you guys treating the the foam edges. In a case where you have a fiberglass pan you will have a bottom edge or more important in the case where you have an alcove stall or tub you may outside corners. I know kerdi band or fleece with thinset is a popular method.
> I think I would consider mitering my boards to maintain the surface.
> 
> Unfortunately, after finally hunting down a couple of places to buy the stuff sticker has scared off the baths I quoted. Very hard to contract bath work as a GC unless your tiling in house.


On the exposed alcove corners, fiberglass tape-mortar on the tub/wet side, hot mud on the room side. Any niche in the wet area gets Kerdi band on the corners. 

When you install the board make sure you lap the Kerdi board over the drywall cut edge. 

Tom


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## Tom M (Jan 3, 2007)

tjbnwi said:


> When you install the board make sure you lap the Kerdi board over the drywall cut edge.
> 
> Tom


Sounds like you are saying route out the foam by joints and lap the facing over the adjoining board. I like that.

I actually meant something a little bit different in the case where you may have one or two tiles beyond a tub. A shower I recently looked at had two tiles beyond the stall then the bull nose on the face of the alcove. So to me I would need to bring out the foam board at least to the corner then I could use drywall in the front. Or just make the connection short of the corner and hot mud like normal prime and tile over that.

Not sure if you're following me


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## tjbnwi (Feb 24, 2009)

No routing. 

Install drywall to the edge of the alcove, install Kerdi. The Kerdi covers the raw drywall edge. Tape with fiberglass tape, mortar on the wet side, hot mud on the room side. If the Kerdi extends past the area to be tiled, mud, prime and paint the Kerdi the same as you would drywall. 

Tom


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## Tom M (Jan 3, 2007)

So relying on fiberglass mesh for a corner is a little lousy to me but I guess it is what it is. 
I would be a little caution about mudding and painting the kerdi on the room side, but if you have not had a problem doing it, I trust your judgement


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## tjbnwi (Feb 24, 2009)

If you're running the bullnose or a tile with trim right up to the edge of the Kerdi that hard surface will protect that corner. The mesh and hot mud are on the room side to be finished off. 

If you're running the tile short of the corner, no reason you cannot use a plastic corner bead. Just feather it in as you would any corner. I avoid steel beads in bathrooms.

Hot mud and drywall compound stick to Kerdi board better than it sticks to drywall. The slightly rough surface is a great tooth for the products. You trust mortar and tile to stay on the Kerdi.

Tom


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## gbruzze1 (Dec 17, 2008)

I always corner bead any backer board, whether cbu, kerdi, or denshield. NoCoat is the preferred product. Am I the only one?


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## tjbnwi (Feb 24, 2009)

gbruzze1 said:


> I always corner bead any backer board, whether cbu, kerdi, or denshield. NoCoat is the preferred product. Am I the only one?


What are you taping the wet/tub/shower leg with? I prefer not to use compound in the wet area. 

Tom


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## tjbnwi (Feb 24, 2009)

You can also wrap the corner with Kerdi band on to the drywall.

Tom


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## gbruzze1 (Dec 17, 2008)

tjbnwi said:


> What are you taping the wet/tub/shower leg with? I prefer not to use compound in the wet area.
> 
> 
> 
> Tom



Are you talking about this...?










You know, I never thought about it. I've always waterproofed with either kerdi or red guard, so the compound was covered. Didn't think about it now with kerdi board. Now that you mention it, I'll make sure to flat tape it with kerdi band. I've always preferred corner bead over nothing or mesh tape in the corner.


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## tjbnwi (Feb 24, 2009)

Yes, that's the side I was asking about. I don't like compound in that area. Mortar down Kerdi band to the Kerdi board, on the room side use hot mud. By folding the band around you waterproofed the raw drywall edge.

Tom


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