master bath project

[zbrn]

First of all, I would like to thank you for a great forum. It has been a great help in planning my master bath remodel.

I will be removing the existing shower and installing a new shower with a bench. I am convinced the Kerdi shower is the only system that I have half a chance of installing correctly. Since I don’t have access to the plumbing after the sub-floor is installed, a mud base seems like the best option.

I have purchased John’s shower book. This was very helpful, but I have a few questions that I hope you can answer.

1. I am concerned about screeding the floor and getting it properly sloped and level at the walls. My plan is the set and level the drain. After the mortar under the drain is set, I am going to scribe a level line on the shower walls using the slope on the drain as a guide. Then I want to screed the perimeter of the shower up to the line and let it set. This will give me hard guides to use to place and screed the slope. It will also keep me from screwing up the drain when I’m mudding the floor. For setting the drain and the perimeter, I am planning to Quikcrete sand mix straight from the bag. I figured a little richer mix would bond better to the mud floor. Do you see any problems with this approach?

2. For the bench, I was planning to use wood framing covered with 3/4 “ plywood. In John’s book, there are pictures showing Kerdi being applied directly over plywood, but elsewhere on the forum I’ve read the it must be installed over drywall. Should the bench be covered with drywall over the plywood? On the sides of the bench, would just drywall over the framing be sufficient.

I truly appreciate any help you can give me. I am going to need alot to make it through this.

Zack

[John Bridge]

Hi Zack, Welcome.

Sorry for the delay. It's the weekend.

Rather than do the mud screeds, I would use Michael Byrne's method of nailing thing strips of wood around the perimeter for your straightedge to ride on. Since the Kerdi membrane will protect everything under it, you can leave the strips in place.

I explained in the book that I use modified thin set (Versa Bond) which is rated to go directly over plywood. I also explained that Schluter doesn't approve of my method and that they prefer the use of unmodified "dry set" mortar for everything. Dry set is not rated for plywood, so the plywood needs to be covered with drywall before the membrane is applied.

Do it my way you can go right over the plywood and void your product warranty. Do it the Schluter way and protect your warranty, but use sheetrock over the plywood.

[zbrn]

Hi John,

Thanks for the response. Delay was absolutely no problem.

The boards around the perimeter is a good idea. If I use dry-set to apply the Kerdi, should I be concerned about it sticking to the wood? Is there something I should put on the wood before laying the Kerdi? It’s only 3/4", so maybe I’m worrying about nothing.

Re: thin-set vs dry-set, I found a lot on the forum about the difference but am still not sure about the advantages of one over the other. Other than being compatible with plywood, are there particular advantages to thin-set, i.e. stronger, easier to work, better tasting, less filling, etc?

I know this is a tile forum, but I also have a plumbing question someone may be able to help me with.

I am starting the plumbing rough-in. The house has three bathrooms. There is a 3” vent on the main soil stack. There are 2” vents on the existing shower drain, the mb vanity drain and the main bath tub. Total of 4 vents. Is it normal to have this many vents? Is there some rule as to where you need vents? One of these is in a wall that’s being removed, so keeping it will be difficult.

Thanks for your help.

[bbcamp]

It is normal to have multiple vents. It is sometimes easier to have more vents than to try to run them all to a single stack.

[zbrn]

So every drain line that taps off the main stack should have it's own vent or be vented to the main stack?

Zack

[zbrn]

Nevermind about the drain question. I did some research and figured out that I don't know what the hell I'm doing. Guess that's better than not knowing you don't know what the hell your doing.

[bbcamp]

Wisdom is knowing the difference.