DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Flooring (http://www.diychatroom.com/f5/)
-   -   What type of mortar? (http://www.diychatroom.com/f5/what-type-mortar-142858/)

cc0353 05-06-2012 08:01 AM

What type of mortar?
 
Hi, I will be doing a DIY bathroom project. I have an old house, and the subfloor is tongue and groove pine planks. I am going to put Hardiboard over that. What type of mortar should I use under the Hardiboard? I bought Multi-purpose polymer fortified thinset. Can I use this under the Hardi AND the travertine tile? Also, can I use this to set my Schluter shower pan, and to adhere the Schluter membrane to the greenboard in the shower, or should I be getting something different? Thx in advance!

JetSwet 05-06-2012 08:53 AM

Quote:

Originally Posted by cc0353
Hi, I will be doing a DIY bathroom project. I have an old house, and the subfloor is tongue and groove pine planks. I am going to put Hardiboard over that. What type of mortar should I use under the Hardiboard? I bought Multi-purpose polymer fortified thinset. Can I use this under the Hardi AND the travertine tile? Also, can I use this to set my Schluter shower pan, and to adhere the Schluter membrane to the greenboard in the shower, or should I be getting something different? Thx in advance!

What is your thickness with size of your T&G planks?
I personally wouldn't install cbu board over directly over the planks, I would install a BC ply then your your backer board.

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

joecaption 05-06-2012 10:47 AM

And even before that your going to have to go back and install 2, screws to every board where they sit on the joist.
Tile will not work on a floor that may move.
1/4 tile board, or any tile board for that matter does nothing to keep a floor from flexing, it's to make sure there's a proper bond to the tile.
The plywood underlayment needs to be subfloor rated, needs to be at a min. of 3/8" thick, 1/2" is better. It needs to be attached every 4" on the edges and 6 to 8" in the field. No glue under it.

JazMan 05-06-2012 08:59 PM

Let me add a few things. But, to sum-up so far you were told to.........

Re-screw the plank floor well and repair/replace as necessary. Install 1/2" or thicker underlayment grade ply, (no cheapo CDX sheathing), fasten only to the planks using 1 1/4"-1 1/2" screws, no glue. !/2" is the minimum over planks, but if the planks are cupped or bowed, they need to be replaced and or go with 5/8" ply instead.

Jet & Joe forget to mention that your joists are probably too bouncy for natural stone tiles. You see, regular ceramic can be installed over a subfloor that has a maximum deflection of L360. Natural stone needs L720. You will probably need to do something to stiffen them.

Tell us the type and size of the joists, the spacing between them, their species and grade would help a bunch, but since it's an old house you may not be able to give that. What condition are the joists, and the span of the joists. Measure accurately the distance from one support to the other. Got pics? Might help.

We can over the thin set and other things when you return.

Jaz

joecaption 05-06-2012 09:15 PM

All good points Jaz was hoping you were going to come on and help.

cc0353 05-07-2012 09:19 PM

The floor planks are 3/4"....joists are 6".....not sure on the span. Half the floor is already plywood...i think i'll just rip out the planks and put dow ply, then The hardiboard. Would that suffice?

JazMan 05-07-2012 09:45 PM

cc0353

Quote:

i think i'll just rip out the planks and put dow ply, then The hardiboard. Would that suffice?
NO! Natural stone requires 2 layers of ply or one plank and 1 ply, hopefully totaling 1 1/4" total or more. If properly installed and in good condition, you will have the L720 criteria necessary.

However the joists system must also meet L720 and I bet they do not, but you've supplied no info yet. Please supply the info I requested otherwise we can't go much further. Double check the 6" joists you mentioned. That definitely does not sound right.

Jaz

cc0353 05-08-2012 06:58 AM

you are right....the joists are about 7 1/4". They are 16" apart in most spots (some are closer together for some reason).

JazMan 05-08-2012 10:30 AM

cc0353
Quote:

you are right....the joists are about 7 1/4". They are 16" apart in most spots (some are closer together for some reason).
OK, sounds better, those are 2x8's which is the smallest lumber generally used for homes. They are adequate to meet minimum code however if the span is around 12' or less +- depending on species and grade.

We still don't know anything since you forgot to tell us what the span is. We may have to guess on the species and grade I suppose.

Jaz

cc0353 05-17-2012 01:56 PM

Quote:

Originally Posted by JazMan
cc0353

OK, sounds better, those are 2x8's which is the smallest lumber generally used for homes. They are adequate to meet minimum code however if the span is around 12' or less +- depending on species and grade.

We still don't know anything since you forgot to tell us what the span is. We may have to guess on the species and grade I suppose.

Jaz

I'm sorry been out of town.....can you tell me what you mean by span? I misunderstood. Is that the distance between headers under the floor joists?

JazMan 05-17-2012 07:33 PM

The span of the joists is the distance between the two supporting objects that hold up the joists. Usually one is the outside foundation wall and the other is the center beam. Measure this accurately from face-to-face.

While doing that see if you can see any stampings on one of the boards. I'm looking for the species and grade. It makes a difference.

Jaz

cc0353 05-26-2012 09:22 AM

Quote:

Originally Posted by JazMan
The span of the joists is the distance between the two supporting objects that hold up the joists. Usually one is the outside foundation wall and the other is the center beam. Measure this accurately from face-to-face.

While doing that see if you can see any stampings on one of the boards. I'm looking for the species and grade. It makes a difference.

Jaz

Ok the span is 10'6". Unk on species/grade.

JazMan 05-29-2012 10:10 PM

OK, you've got 2x8 joists, 16" on center, spanning 10'6". Even if I select Southern Pine grade #2, your floor does not meet minimum standards for natural stone. Southern Pine is the stiffest species generally used in home construction. #2 is the common grade used for joists, but #1 aren't good enough either. The finest grade is Dense Select Structural, which won't make the grade either.

I would suggest you find a nice porcelain tile that mimics the look you want.

Jaz

cc0353 05-31-2012 11:27 AM

well that's a bit of a bummer! I appreciate the info, I had no idea!

Regarding the Schluter pan, what is the best way to install the drain pipe? We do not have access from below, but the plumbers had the floor open on top and the drain is in the floor ready to go. Ideally we'd like to lay the pan first, then membrane, then tile, then glue in the drain (PVC). Will that work ok? I watched the video that came w/ the kit, but am still a little unclear on it.

JazMan 05-31-2012 07:40 PM

Quote:

Ideally we'd like to lay the pan first, then membrane, then tile, then glue in the drain (PVC
NO, wrong. Drain over the tile? HUH? The membrane has to go over the drain.

The 2" waste pipe should be plumb, centered and trimmed to the correct height. Make sure the trap and pipe is well supported so it does not collapse when you push the drain to install. Then install the Kerdi tray. Then the Kerdi Drain, glued into the pipe of course. Then the Kerdi Membrane.

Jaz


All times are GMT -5. The time now is 10:02 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved