which waterproofing system for new shower?

[johnfrwhipple]

Mtcummins you seem to be a little slow understanding the TTMAC and ANSI Specifications.

Neither of the industries top organizations include drywall in shower construction. When drywall is referenced it makes further notation to include the words "Dry Area Only".

In the shower receptor drawing details as well dry wall is not listed.

So to repeat.

You can use water poofing over drywall, Kerdi, Hydro Ban and Aqua Defence etc. - just not in showers. Schluter does have men working in these orgaazations and if drywall was accepted in a shower they would have included it in the manuals. But they didn't because it is not accepted.

Your in Pittsburg, PA - in Pittsburgh your local Bureau of Building Inspection - (412) 255-2175 can offer you more guidance on proper shower construction procedures. I spoke with them this morning and Pittsburgh follows the International Building Code. The International Building Code removed drywall from acceptable backer boards in showers a few years back - I guess you missed the memo. If you order that code book you will not find drywall listed under shower backer boards. Maybe try emailing the building department and asking them if it is OK. BBI_DPWRequests@city.pittsburgh.pa.us

I got a hold of Eric in the Inspection Burea and we discussed this. I was told that in Pittsburgh a single family home would fall under the IRC. Under showers and tubs it mentions something like a non-absorbat backer board material is to be used.

Dry Wall is not non-absorbant. We discussed vapour barriers and his take on them and at the end of the call I asked him what he would use in his own shower if building new. Eric said cement board or wonder board.

I would think this very loose text in the building code would open the doors up to many crazy designs.

If you read this Document from Gypsum Nexus you might fell a bit better about not understanding all the new code changes. At the bottom of the first page on the right it makes mention that Green Board (water resistant) drywall is permitted in a bathroom renovation but not in the "Wet Zone".

So you have the people that make drywall say No - drywall is not allowed in wetzones of showers.

You have the International Building Codes change to exclude drywall from the Wet Zones

You have TTMAC and ANSI repeating the fact that drywall is not to be used in wet zones

You have the IRC stating a non-absorbat material is to be used.

And you have Schluter (and others) saying drywall is an approved substrate. Of course they say that because sometimes people like me like to waterpoof more than just the wetzone and we bring our membranes out past the backer boards.

I hope this helps.

JW

[mtcummins]

JW, why don't you try reading sometime, rather than just responding with crap.

http://www.schluter.com/media/ShowerHandbook.pdf

NOTE: this is the SHOWER, let me repeat, SHOWER installation handbook from your reps that are on all your boards. One more time, this installation manual is for installing SHOWERS, not backsplashes, or whatever else you're claiming w/o any basis. Look at page 2, then look at page 5, then how about page 7, oh, then there it is again on page 9. Oh wait, not done yet, there it is again on page 11. Then there are the pictures on page 12, 14, 15, 17, 19. There's probably a lot more, but I'm already tired of being right.

I will note one more thing... Read page 19. It specifically talks about protecting gypsum board in a wet zone with kerdi. Hmm... that doesn't sound like the bull crap you've been saying on here...

[johnfrwhipple]

That is a Schluter install book. Not a code book. You must then think it's OK to build a shower curb out of 2"x4" 's and drywall as well I'm thinking. If you kerdi it of course. I heard about a hotel in Las Vegas that tried that. They failed and replaced them with Noble Showers, or so I'm told.

The book (Schluter Shower Handbook) also shows water beading on Kerdi when it actually wicks.



Here is a picture of drywall and Kerdi Board wicking water. I find it interesting that the kerdi Board wicks water more than drywall. Don't you?



Look how Kerdi wicks the water above the flood line.



Someone posted once Kerdi is Magic and it doesn't leak even with a pinhole. I tested this theory as well and to be fair tested Noble Seal TS - guess what? They both leak when poked with a hole.

Did you can your inspector to find out if you can use drywall in Pittsburgh, PA? I emailed them for you in case your too busy.I'll post the info once I hear back. Can't wait to hear what your local inspector thinks. Probably tell me "No".

How many showers have you build in Pittsburgh with drywall? Did you mud and tape the seams? Can you use Kerdi over drywall mud or does it just have to be the plain paper? http://www.nationalgypsum.com/resour...pWallBoard.pdf Great Dry Wall resource. Funny no mention of Kerdi and a shower detail??? Seems like the only place that says you can use drywall in a shower is in the company handout? Odd. Imagine if you followed the advice and built your curb with drywall over 2"x4" studs? What a recipe for disaster.

[jadnashua]

ICC-Evaluation report ESR-2467 was Re-issued August 1, 2011 (and valid for two years). In this, they state Kerdi and Ditra are approved waterproof membranes, and Kerdi in a shower construction is specified for use over various backing materials.

In it, it specifically states gypsum board (drywall) as one of the backing surfaces IN A SHOWER as required in IRC Section P2709.2 and IPC Section 417.5.2 when installed per the manufacturer's installation handbook.

Kerdi and seamed Ditra must use an unmodified to seam the materials to prevent latex problems (wetting). Any membrane can leak if you poke holes in it.

I'm checking on Canadian approvals/restrictions, but that is taking me a bit. Local codes may trump national ones, but in the USA, the IPC testing and approvals exist for Kerdi in a shower over gypsum board (drywall).

[mtcummins]

JW, is it gonna take you 10 years to realize/admit that you are wrong, like it took you 10 years of installing Schluter products to realize that they were "junk"? Just admit it already, you're wrong. That doesn't mean you have to like the practice of installing Kerdi on drywall, or advocate it, but stop making up code restrictions that don't exist, telling us that Schluter does not approve of kerdi on drywall in a shower, and all the other bull crap that you spout off.

If you actually want to make a difference like you claim, you should stop being a subborn jack***, admit that you were wrong about this issue, and then still explain that you don't think it is good practice and that you think people should not do it for REAL REASONS, not b/c of some obscure code references that don't actually support exactly what you're saying. The way you've acted on this issue, I'll never listen to what you say again w/o questioning it extensively, and getting confirmation from guys like Jim that what you are claiming is actually correct. You will never make a positive difference like you claim to want to by being a dick.

[johnfrwhipple]

Kerdi is not approved over drywall. Only Schluter states this.

If your local building inspector allowed it once does not make it acceptable. I'll check in on a few bureaus in New England and ask Jim's inspectors if they allow it.

Promoting shower's build with drywall is crazy. If 10 people purchase cement board and flood test their shower build - I've already made a difference. I've helped dozens of people flood test their own showers in the past year. Most of whom live in another city and another country - Yours.

People want to build better. People are tired of paying for crap and paying well for it.

Mtcummins and Jim you have sent me off on a new baby mission. Lets call around a few cities and ask the building departments what they allow. No offence to you men but I doubt any of you have even build a shower in the last 24 months let alone waterproofed one. Can either of you show me some install pictures of a shower build with drywall and a flood test report signed off on by an inspector? I won't hold my breath. While you sort that out I'll keep calling for flood test inspections and sharing inspector reports. You keep selling the drywall angle and I will call a new city each morning and will do a survey of sorts.

[mtcummins]

You have a very convenient habit of ignoring every code citation that someone makes that proves you wrong. Hmm... funny how you can be "right" when you ignore any evidence to the contrary...

You have fun with your little mission. I don't believe that you will do anything properly even in that, so your results will be as meaningless as the obscure code references you like to make. Sure, if you call my inspector and ask if drywall is an acceptable tile substrate in a shower, he's doing to say no. B/c of course it's not. Just like your code references, it isn't an acceptable tile substrate. People used to tile greenboard for a tub surround... thats crazy, and against code. All the bullcrap references you've made to code just state that obvious restriction.

If people want to pay for cement board, i never said anything was wrong with that. I think it is probably a better installation. I never said anything to the contrary. What I did say is that you're full of crap in your statements that it can't be done over drywall.

[johnfrwhipple]

MTCummins when you install tile and want to check your coverage rates you left a tile up to see. You want at least 80% coverage.

The simple act of lifting a tile causes suction. Like a shop vac pulling on one spot.

In your "Code Book" or "Schluter Hand Book" to use a proper name Schluter mentions that tile can be installed right away. Have you ever vaccumed Kerdi the next day? The same day? Do you know what happens when you vacum fresh Kerdi? The Kerdi pulls away from the substrate.

Now because Schluter says it's OK to set tile right away I don't. Not because I don't think the Kerdi will fail this process, but because I know Kerdi will fail this process. How do I know? I installed Kerdi for a decade.

The Schluter handbook also lists a flood inspection if nececessary. They are.

Jim put up an ICS report that said Kerdi can be installed over drywall. An ICS report is used to get a IAPMO Certification. The IAPMO certification is key, not the ICS. Yet you need the ICS to obtain the IAPMO.

Lets repeat.

In no industry specification book does it show a shower built with drywall.

Yes you can set Kerdi or a liquid membrane over drywall. If it is for something other than a shower, is in a non wet zone and is interior not exterior.

I have found that thin set does not bite well to drywall that has been mudded? When we set tile over drywall we vaccum it for bond breakers, wash it gently and use a high quality modfied thinset. Some times we first prime the drywall. Schluter does not spec the process of the drywall and with this insane set up you have a gypsum board producer, a waterproofing membrane and a thinset company in the mix. If you wanted to go against all industry guidelines and use drywall, One would reason that using juts products from Laticrete, Custom or Mapei would make more sense.

I spoke the other day with my Mapei rep and he thinks drywall is a horrible idea in a shower. He warned me against moisture vapour building up and failing the back side of the drywall. We spoke a bit about what a poor building practice this is and shock are heads in disgust that this practice goes on.

Show me any tile organzation that endorses drywall as a backer board. Not a supplier, because they are selling you something. But an organaztion that's interests are to promote proper industry standards and industry best work practices.

Have to go. I joined the ASTM and this morning is my training class!

[jadnashua]

John, I don't know if you can't or won't read...the report from a national testing agency states Kerdi and Ditra are waterproof, and lists the associated build approvals. The test had them build a structure, using the manufacturer's instructions, and then flood test it. Drywall is listed as an acceptable backing material IN A SHOWER (although they state it as gypsum board in the document, same thing). If you can't or won't believe the IPC certification, that's okay with me, but when you continue to state that it doesn't work and isn't approved, you're totally off base. From what I've heard, you've been banned from multiple websites for your continued knocking down of products. It's one thing to state you prefer a different brand, but it's another to state a product with approvals is bogus.

[johnfrwhipple]

Jim I have tested all liquids with drywall and they pass flood tests as well. I make simple boxes to check new stock.

What you seem to ignore is that Schluter does not set industry guidelines. Even with some of their top staff on these organization boards you do not find drywall listed as a backer board in any organization. This is my point and the point you seem to skirt at every post.

Drywall is not an approved backer board in wet zones (TTMAC & ANSI). If it was it would be listed with an elevation detail. If you can show me a drawing produced by TTMAC or ANSI outlining this method I'll eat crow. I'll hold tight while you find it. Until then I will continue to inform people that Dry Wall is not acceptable because it's not listed as one of the approved backer boards in any industry guideline.

Jim would you use dryall over wood studs and then kerdi to build a curb? I bet that the outside edge crumbles the first time someone steps on it. Schluter says it's OK in their handbook - is it? Do you have any expanded details from Schluter? Perhaps a line drawing? Come on Jim....

Jim here is the Boston Inspections Service's contact information;

Plans & Zoning Division
1010 Massachusetts Avenue, 5th floor
Boston, MA 02118

Tel: 617 635 5312
Fax: 617 635 5399
Email: ISDplanzon@cityofboston.gov

I sent a request for clarification for you.

[jadnashua]

What you seem to be missing is that independent testing agencies have tested and approved Kerdi for use over drywall in a shower. The IPC being one of them. TCNA another.

Kerdi is NOT approved for installation over wood, never was, never will be, so, if you want a curb out of wood, you sheath it in drywall or one of the other acceptable backing materials as listed in the testing spec and approval, or, build it out of something else.

Directly from the ICC Evaluation Service Report ESR-2467, Section 2.0, it lists the specific approvals. I could not cut this and paste, so I'm retying it:
"KERDI is also used as a shower lining, as required in IRC Section P2709.2 and IPC Section 417.5.2 over concrete, mortar, tile backerboard, expanded polystyrene foam board, prefabricated polystyrene shower trays, curb and ramps, gypsum board and masonry substrates."

In section 4.0 INSTALLATION, it says the following:

" Installation of Schluter (tm) - KERDI, Schluter (tm) - DITRA and Schluter (tm) - DITRA XL membranes and accessories must comply with this report and the manufactuer's published installation instructions."

The manufacturer's instructions show and list the same backer materials as above from Section 2.0. The TCNA guideline that also was tested and approved was referenced earlier and is listed explicity as an approved method. Now, my copy of the spec is a little older, but there have not been changes in that approval. It clearly shows gypsum board (aka drywall) as the backer in the construction detail as an approved shower construction method.

Both Kerdi seams and Kerdiboard edges MUST be sealed with the specified overlap of seaming material, either Kerdi, Kerdiband, or KerdiFix, otherwise, it is not a waterproof ASSEMBLY. You stick a piece of cbu in a waterbath, and it will wick water just as easily as Kerdi until it is either sealed on the surface or otherwise installed per an approved method. Just setting it in water has nothing to do with whether it is waterproof when installed properly.

The approval page from the State of Massachusetts http://license.reg.state.ma.us/pubLi...kerdi&psize=50

[johnfrwhipple]

...The TCNA guideline that also was tested and approved was referenced earlier and is listed explicity as an approved method. Now, my copy of the spec is a little older, but there have not been changes in that approval. It clearly shows gypsum board (aka drywall) as the backer in the construction detail as an approved shower construction method....

What level of drywall finish is spec'd Jim?

Just board.

Board and metal corner bead.

Board, tape, finish mud.

Board, tape, finish mud, priming?

Pretty grey area.

JW

[mtcummins]

What level of drywall finish is spec'd Jim?

Just board.

Board and metal corner bead.

Board, tape, finish mud.

Board, tape, finish mud, priming?

Pretty grey area.

JW

But what isn't grey is the fact that you've been spouting bull crap all this time. That's pretty black and white.

What do you use when doing cbu? Just board? do you fill the seams? use mesh? cover screw holes? corners? clean the surface? Pretty grey area JW.

I don't finish drywall when using it behind waterproofing. I'll fill the voids with thinset if anything. When I'm feeling particularly fussy, I'll plan it out so that the kerdi overlap falls into the seam between boards, so that there's no build-up from the overlapping. But that doesn't work out as often with drywall as with cbu, as the widths don't line up as neatly.

[jadnashua]

I know I read it somewhere about prepping the drywall before installation of Kerdi. You don't need drywall mud or mesh tape...the Kerdi is far stronger than the tape anyway. If your taper portion of the drywall is to be covered with Kerdi, you can either fill it with thinset and immediately install the Kerdi, or fill it flush, let it cure a bit, then install the Kerdi on the now flat plane as it it wasn't there. In some orientations, the taper will help avoid the small buildup in the changes of plane - far easier than with the much thicker membranes.

[johnfrwhipple]

I have had more than one setter tell me that Kerdi peels away if there is any drywall mud over the board.

I have see guys scrap it all off.

One guy uses Hydro Ban first to seal the drywall.

What is required to maintain a warranty from Schluter. So if it fails your covered.

Or will it be "Kerdi is not allowed over that type of drywall compound"

Can it go over Cement Fill from Synko?

Can it cover over 30 minute?

Do curbs need outside drywall corners?

When waterproofing over a CBU we always tape the seams first. This is a required step in CBU boarding.

The use of metal corner beads and such is also required with drywall. I would think you need to follow the manfactures guidelines???

If this is all approved with the TCNA why does it not appear in the ANSI Specification guide? The new one.

Your guide is outdated I think you said Jim.

Have you men really build a curb with wood and drywall? Can you say "Hack"

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++

Inspired by Jim's posting of his favourite backer board "Dry Wall" I thought a new series of testing should be done at the SunnyCrest Lab. I broke out a sheet of plexiglass and cut it up into small stock. I then covered each sheet with DryDex and drywall spackling compound.

This "Drydex" is great stuff. When your painting sometimes you can sand too quickly a drywall patch. This product goes on Pink and dries white.

Yesterday I set the DryDex to the plexiglass and today I will skim these samples out with regular drywall compound (Synko - Classic Finish)

I'll let these new assemblies sit for a few days and then I will Kerdi a few and use liquid on the others.

I'm going to make some boxes - cover them tight and just sit back and watch. If any of the waterproofing measures do not work with drywall the water should leak to the bottom and reactivate the DryDex and turn it pink.

Seeing is believing, and this will prove to me with no doubts if waterproofing can be applied over drywall.







JW