Colman's Powder Room Project [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-13-2010, 09:51 PM
1st time laying tile. I'm starting with a small 6' x 3' pwder room (no shower or tub). I stripped the floor down to the tongue and groove subflooring. I was going to put down 1/4" hardibacker and then tile. Do I need to use 3/8" plywood uder the hardibacker?

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02-13-2010, 10:24 PM
as long as you thinset the hardyboard to the tongue and groove and nail or suggested screw into the joices you shouldn't need plywood.

02-13-2010, 10:32 PM
Hi Coleman,

Sorry Ryan but you are wrong on this one. Coleman, you need plywood for sure. I would recommend 1/2" B/C underlayment, then the 1/4" Hardie with thinset, tape & fasteners etc.


Houston Remodeler
02-13-2010, 10:57 PM

Tool Guy - Kg
02-13-2010, 11:27 PM
Hi Ryan,

We aren't perfect around here, but when advice is dispensed against industry standards or manufacturer's directions, it's generally corrected. Jaz and Paul are correct in the need for plywood (at least 3/8" CC exposure 1, plugged and sanded).

The reason for the plywood is dimensional stability. Solid wood, like that T&G subfloor, expands and contract too much to install backerboard directly over. Plywood is far more dimensionally stable.

Secondly, it sounds like you're recommending screwing the Hardibacker directly into the floor joists. That's also incorrect. The Hardibacker should be fastened to the plywood only with screws that won't penetrate into the joists...there are special screws Hardibacker sells that are only 1 1/4" to 1 5/8" to help out in this department...this method of install helps isolate some structural movement from reaching the tile assembly.

One last thing, Ryan...It sounds like you might be a pro. If so and you'd like to help out with answering questions, please introduce yourself in the Pro's Hangout. We're a friendly bunch, but like to know a bit about the folks who are dispensing advice on our forum. :)

02-13-2010, 11:41 PM
Thanks for explaining the reason for plywood..I will try to be more careful on the advice I give

02-13-2010, 11:45 PM
So the plywood is screwed directly to the subfloor and then thinset under the hardibacker? Or do you put thinset under the plywood too?

02-13-2010, 11:49 PM
I would like to call myself a tile setter .I am finding myself to be humbled by this forum. I am realizing I have just touched the surface when it comes to flooring. Thanks for the wisdom

plywood would be nailed every four inches on seems and six to nine in center joices,no thinset under plywood. Im sure they would agree.

Houston Remodeler
02-14-2010, 12:02 AM
correct, no thinset or glue under the plwood

Tool Guy - Kg
02-14-2010, 01:03 AM
With that thin 3/8" plywood that doesn't like to lay flat, 4" O.C. around perimeter and 6" O.C. in the field. Take a look at this thread in the Liberry on Plywood Floors (

In the same thread, also note this article on Position of Underlayment ( written by Peter Nielsen and Dr. Woeste. :)

02-14-2010, 08:12 AM
Thanks everyone for your detailed responses, very helpful. One thing I neglected to mention is that I only have 3/4" to lay flush with the toilet flange. Prior floor had tile around outside of toilet, It did not look good.

Brian in San Diego
02-14-2010, 08:35 AM

If you can't replace the toilet flange (but I would consider it if it's old) you can lay tile and be higher than the flange. Wouldn't make an inspector's day but it's done all the time. Then one would use a flange spacer to get the flange at the finished floor height.


02-14-2010, 09:58 AM
But to be really correct the toilet flange is set on top of the finished flooring. :shades:

From the Liberry -Toilet Rough-In (

02-14-2010, 12:04 PM
This question is going to show my inexperience, but should I use nails or screws to fasten the plywood. I will be using the hardibacker screws to attach the hardibacker. Thanks.

02-14-2010, 12:11 PM
Colman, get yourself some decking screws approx 1/4" max longer than the total thickness of the ply and the t&g boards below. then screw away, following the perimeter/field schedule given above.

I like Deckmate or Phillips-Squar-Driv screws from the box stores myself.

02-14-2010, 12:40 PM
No Shame, Colman. We all learn stuff here.:)

02-14-2010, 02:41 PM
I want to thank everyone for their helpful responses. Last question as I'm starting to become concerned with the height of the floor. Is it ever ok to tile directly over the plywood, without using the cement board?

02-14-2010, 03:06 PM
It CAN be ok to tile directly to plywood, but it's pretty hard to make it conforming to the strict requirements for layers, fasteners, thinset coverage, etc. It's a lot easier to do it w/ better substrates, which is why you'll see us recommend using CBU's, Hardie Backer, and Ditra a lot. THere's plenty others out there, too. If it's proven better, whyn't use it, right? :)

gitchi gummi
02-14-2010, 04:50 PM
As far as screws, you really can't beat GRK star drive for ease of use. They are NOT usually found at the big box, however.

There are a number of "waxless" toilet install solutions that fit the toilet bottom flange and penetrate down into the floor flange and pipe 4" or so. This may work well for you.

Hope this helps.

02-21-2010, 09:22 AM
I finished laying a tumbled travertine fllor in my powder room yesterday, now I am wondering if I should use a sealer/enhancer prior to grouting or wait until afterwards. Also, I noticed thinset on the face of a tile or two. Any suggestions on how to clean them off? thanks.

Houston Remodeler
02-21-2010, 09:29 AM
I prefer to seal travertine before grouting. It makes cleanup easier and the dyes in the grout won't change the color of the tile.

To remove thinset; grab a popsicle stick or paint stirrer and scrape away at it. Thinset should come up easily. You'll get a nice shoulder workout. Any residual thinset can be buffed off with an old terry towel

John Bridge
02-21-2010, 09:32 AM
Hi Colman, :)

The best way to remove the dry thinset is to scrape it off. If the travertine is not polished you can then sand with wet/dry paper -- about 600 grit. That will restore the honed finish.

I would do the enhancing before grouting. We've had episodes of enhancer messing up the grout color -- blotchiness. Also, make sure you test some scrap pieces to ensure you like the result. :)

02-21-2010, 09:34 AM
Thanks Paul, I was going to get an enhancer/sealer from one of the box stores. Does it matter which one I use?

Houston Remodeler
02-21-2010, 09:37 AM
Aqua mix enhancer pro, sealers choice or miracle 511 will do the job. Some travertines aren't too absorbtive so use some patience. Don't let excess sealant dry on the tile. If it does, add some more to 'melt' the excess and wipe it all away with a dry clean old towel. Stay away from water based sealants. Look on the label for the cleanup instructions. It shouldn't say 'cleans up with water"

do a test on a few tiles first.

03-02-2010, 07:29 PM
Thanks in large part to the advice I received here after 3 weekends I'm finally done tiling my powder room and I think it looks great. All that's left is to install the new toilet, which brings me to my question. Right now my flange is about 3/8" below the finished tile, so if I use a 1/4" extender I'm still about an 1/8 low and if I use a 1/2 extender I'm about an 1/8 high. I've seen differing opinions on which is better and I'm wondering if its better to be a little low or a little high. Right now I'm leaning towards using the 1/4" extender and an xtra large 32B wax ring. Any advice?

Brian in San Diego
03-02-2010, 07:39 PM

I merged your three different threads on this project and gave it a new title. Hope you like it.

I would go with a little under and use a wax-free toilet bowl gasket ( I have incorporated them into two of the toilets in my house. No waxy mess and they can be adjusted for various situations.


03-02-2010, 07:53 PM
Thanks Brian,

This is by no means my specialty, but I'm a bit of a traditionalist. I just don't know enough about the wax free gasket to try it.

Houston Remodeler
03-02-2010, 10:34 PM
Think of them as big, soft, non absorbant (closed cell) spongy O rings that are made for terlits.

03-03-2010, 08:08 AM
I appreciate all the advice given on this site, but I think I'm going to stay with the wax ring (tried and true), but i'm still not sure if its better to be 1/8" lower than the finished tile and use an xtra large ring or be an 1/8" high and use the standard ring. I've seen differing opinions. Any advice would be helpful. Thanks.

03-03-2010, 08:41 AM
You want the top of your flange to be about 1/4" higher than the tile. In other words, it should be as high as if you mounted the flange on the surface of the tile, where it would be in a perfect world.