Kerdi Shower: Afraid of Inspection [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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Guitar Charlie
10-13-2006, 10:28 PM
I am doing my first Kerdi shower (32" x 60") and I am afraid of what the inspector may say or worse fail me bacause he is unfamiliar with Kerdi shower system. If I tar paper the studs and hardibacker over it and then kerdi and tile will this cause a problem? I have a feeling that by having two vaopr barriers problems may occur. The only reason I am prone to installing the tar paper and backerboard is purely for the inspector, if I had my way I would use hardi backer alone or sheet rock. I am sure this question has come up before, should I be concerned about two vapor barriers in this situation? Or should I try to educate the inspector?

Thanks for all the help.


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10-13-2006, 10:36 PM
Hi Charlie, you don't want two vapor barriers. I would try to educate the inspector on the Kerdi if possible. I did it up here. Give him the disc that comes with the drain or send him to the site.

10-13-2006, 10:47 PM
Mike2 has posted on here somewhere all of the plumbing code numbers that verify Kerdi is good to go. I can't help you where. Sorry
Do search Kerdi certification and see what you get.
Good Luck

10-13-2006, 10:50 PM
Non-conventional materials which are not Code should concern you.

I would pull all the materials from Schulter's Site, including the data sheet and instructions and present them to the inspector BEFORE you pull the permit and BEFORE any inspection. Try to get permission before you start.

If approved in advance, use a digital cameral to make a record of how it was installed, e.g., per instructions.

You will have some issues for the rough out, because you will have a shower without a pan membrane, just the plumbing and a preslope. But hang in there, and try to understand that in building inspections, it is better to ask permission than forgiveness.

Finally be prepared to do a flood test and let it sit for the full 24 hrs. Hopefully, he will approve the Kerdi.

I've given up down here. I just make the showers out of conventional materials. Kerdi may be fine, but I don't have the time or patience--and it isn't THAT good--I mean one can make a perfectly good shower using mud or CBU, or if one wants to bullet proof it, using Laticrete 9235--so I just go with the flow.

Party On.......

10-13-2006, 11:08 PM
Don't do the two barriers, Charlie. One or the other.

The certifications for Kerdi can be found here ( in our Liberry.

Selling it to the inspector is up to you if it hasn't been adopted in your jurisdiction. We've heard of it being done in California, and we've heard of it being flatly refused. You pays your money and takes your chances.

Might be worthwhile to call Schluter and ask about their experience in that aspect of the product. Perhaps they've developed some good tips for convincing inspectors.

My opinion; worth price charged.

10-14-2006, 09:47 AM
Just adding another vote to get with your inspector or Planning Dept. before hand. Take all those materials with you and get it pre-approved. :nod:

10-14-2006, 10:36 AM

Initally I ran into the same issues and it took a good deal of footwork to educate the inspectors. I went to the head inspector first at the county building dept. I sat down with him and explained the system gave him a folder with all the Schluter data, video ect for his file. Before all was said and done I was in the inspectors home doing a Kerdi shower for him...needless to say he got a heck of a deal :D

Since then he has taken an active role in educating his fellow inspectors on my behalf...It's worked out very well, especially as I go to other counties that are unfamilar with the system. I refer the new inspectors to him and the credability is almost instant.

I think a fair amount has to do with how progressive the inspector is, but it always has to do with how you approach it too. The point about doing all this well in advance of your project is important. They may consider it disrespectful and be hesitant if they "catch" you trying to educate them with a project that is already half-done... :bang: Just be knowledgable and friendly, I think you'll do fine.

10-14-2006, 08:36 PM
Charlie - when you call Schluter get the name of your regional rep and contact him/her. If you're lucky he'll be familiar with your area. If not, it's a learning opportunity. I found the rep for my area very helpful and knowledgable about the product, though I wasn't messin' with inspectors like you are. :goodluck:

10-15-2006, 11:23 AM
While reading the forums for other info, i accidently came accross the double vapor barrier problem as well. I had allready installed a vapor barrier behind my drywall, but fortunatly i hadn't installed the kerdi.

I e-mailed the schluter rep for my area asking him the specific question on the double vapor barrier. He replyed within a couple of days recomending the vapor barrier be removed. I approached the plumbing/building authority with a copy of his reply, the schluter approvals and installation methods and was granted the okay within 10 minutes.

I'm a electrical inspector by trade, i run into new products everyday, what most people and lots of inspectors don't know, is that 9 times out of 10 as long as the product is approved, manufactuer's installation instructions trump the code.

Being up front and honest with the inspector will get you alot futher ahead than trying to hide things.


Guitar Charlie
10-15-2006, 10:20 PM
Thanks for all the suggestions, I will try to educate the inspector. Having the IAPMO certifications should be money in the bank for this one. I will definitely have that printed out for him. I will call the city (Napa, CA) ahead of time and see what the head inspector says as well.

Thanks again,


10-16-2006, 07:14 AM
Be sure to let us know how you make out, Charlie. We have people with this same situation alla time. :)