Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Ceramic Tile Advice Forums - John Bridge Ceramic Tile (https://www.johnbridge.com/vbulletin/index.php)
-   Tile Forum/Advice Board (https://www.johnbridge.com/vbulletin/forumdisplay.php?f=1)
-   -   Toilet floor plates (https://www.johnbridge.com/vbulletin/showthread.php?t=130111)

joe14580 11-23-2020 07:23 AM

Toilet floor plates
Hi guys,

Starting another thread to focus on this issue.

Bathroom remodel, we tore up the old floor consisting a 1/4" Luaan with 2 layers of vinyl flooring on top. The subfloor is made up on 4" wide hardwood boards maybe 3/4" thick and is in good shape, there are narrow gaps between the boards lengthwise probably to allow for expansion. I'll be laying 1/4" Durock adhered with thinset onto the existing subfloor and installing Porcelain tile on top.

It's then I see the toilet sits upon a plate made of what appears to be slate, it's not thick but it sits above the level of the hardwood-plank subfloor.

Sidenote: We just had a house built with Advantech subfloor and I recall there was no toilet plate, just a toilet flange surrounded by subfloor, so the toilet sits on the subfloor. I could be wrong about that but I don't think so.

Do I abut the Duroc up to the slate plate and have the tile also follow the contours of the slate ? Is the slate plate necessary ? Are they still used ? Are they functional, ornamental, or both ? Obviously it'd be easier for an amateur to remove the plate and trim the Duroc and tile around the flange.

Thanks, this board is the best.


ss3964spd 11-23-2020 08:58 AM

This the same project as your recent shower wall thickness post, Joe?

First off, you cannot install Durock directly on toppa sawn plank boards. Well, you can, but not according to Durock or probably the TCNA, both call for installation over plywood and, in your case, that plywood will need to be at least 1/2". The sawn planks are just too unstable, hence the need for plywood.

Regarding the toilet plate; I can't imagine what that's all about so a photo would sure be helpful. But in short, the actual toilet drain flange should rest solidly upon the finished floor, not the sub floor.

joe14580 11-24-2020 04:43 PM


Yes same project, I just wanted a seperate thread in case some wanted to do a search in the future.

Thanks for the info re: Duroc over plank, understood.

It's my brother's house, I'll have him provide a pic when he gets home.

In the meantime, let me ask it this way. After I place the plywood on the plank floor (cut to fit around the toilet flange), then install the duroc, also cut around the flange, can I then install my tile (cut to fit around the flange) and place the toilet directly onto the porcelain tile ?

This floor plate thing is simply a flat rectangular piece of 1/2 " thick slate routered into the plank floor, it's what the toilet sits on for support. Previous floor had no tile, only 2 layers of vinyl floor.

Tool Guy - Kg 11-24-2020 07:15 PM

Hi, Joe.

We generally like to keep projects together because the info from one part of the project is typically related to another. As a long time remodeler, I can make predictions of concealed portions of one part of the house based off of what I can see both at the place in question and the surrounding areas. Keeping threads together makes it a little more like we are walking through the house and can often tell you things you need to know, but didn't ask. Splitting stuff up shields the person helping you from info that might give you very customized advice. Thanks for thinking about future people looking into this subject and learning. But you’re more important to your own project right now than some unknown person in the future.

As far as the slate: it sure sounds like someone’s idea of a good repair for some reason that was important to them at the time. The most ideal floor would be a proper subfloor, tiling substrate, and tile with a hole through them all and a toilet flange supported atop the tile. But remodeling often forces folks to have to compromise something away from such an ideal scenario. A couple pictures would be welcome (from both above and below the floor).


jadnashua 11-24-2020 07:25 PM

The floor plate is a Rochester, NY, Monroe County thing...it used to be a requirement for installing a toilet. I think they thought all toilets would end up leaking, and rot the floor out, so having a stone plate underneath was a good idea! I ran into that long time ago when I was helping my sister at an older house in the city.

As said, planks, especially those that aren't T&G are not a great support for tile without some help.

If you want to minimize the overall buildup, a 1/2" ply, then something like Ditra would gain you about 1/8" and is easier to install, cut, and carry home than cbu. There are specs and instructions in the 'liberry' on what ply and how to install it.

joe14580 11-25-2020 04:26 AM


Did a little googling and you're correct, it seems to be a local Rochester NY thing. I'll remove it.

When I place the 1/2" plywood onto the existing 3/4" non-T&G plank floor, do I use thinset between the plank and plywood or do I just nail the bejeebus out of it.

cx 11-25-2020 09:49 AM

You do not wanna try to glue the plywood to the sawn board subfloor, Joe. Just fasten the plywood to the boards with mechanical fasteners. You want to be sure your boards are well fastened first and then fasten your plywood only to the boards and not the joists. I much prefer to use screws rather than nails on all parts of a subfloorm 'speically when a ceramic tile installation is involved.

My opinion; worth price charged.

SpaceCadet 11-27-2020 06:12 PM

Why no glue, cx?

cx 11-27-2020 06:46 PM

Two reasons, Paul. First, it doesn't work well because the boards are usually not sufficiently flat to glue with a full spread of wood glue and the fastener schedule for the plywood would not provide a suitable clamping schedule at the boards.

Second is that the whole reason for the plywood is to isolate the surface from the movement of the boards and there's no reason to do anything to limit that.

My opinion; worth price charged.

SpaceCadet 11-27-2020 09:35 PM

I thought the adhesive would bridge the voids between plywood and uneven floorboards and work like a shim. Does that not work?

jadnashua 11-27-2020 10:28 PM


Originally Posted by Paul
I thought the adhesive would bridge the voids between plywood and uneven floorboards and work like a shim. Does that not work?

The reason why there's a minimum thickness of ply is so that it can support itself as long as it is screwed to the existing subflooring material. But, that first layer of planks must be anchored well to the joists first, if required. As was said, the reason to use ply over the planks is because plywood is MUCH more stable than dimensional wood, so it doesn't change as much with temperature or moisture content changes. What tends to happen if you try to glue solid wood to plywood is that the differential movement can put a lot of stress on the joint, and literally break it over time. Prior to that, it tries to transfer its movement through to the other layer, which you are trying to avoid.

All times are GMT -6. The time now is 12:02 AM.

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC