Tile and slate floor ???

Clutchcargo · 12-26-2007, 07:03 PM

I will be redoing my foyer floor with either slate or tile. I need to determine what the floor thickness will be for a new staircase that I'm putting up.
The floor is 2x8 joists 16" OC with a 12' span and a T&G plank subfloor. How much do I need to build it up to have a floor that is stiff enough for tile surface? Do I need to add a layer of 3/4" ply or will blocking between the joists
TIA

Rehabber · 12-26-2007, 08:11 PM

Your current floor does not meet L360 (the minimum required for tile)If you sister the existing joists with another 2x8 you will jump to L603 which is enough for tile, but still not enough for stone. You will need to put 3/4" plywood on top of all this, then yor backerboard of choice or Ditra.

Clutchcargo · 12-26-2007, 09:58 PM

L360/L603???...OK, back to the drawing board.
I just realized I don't know enough to know what I don't know. I'll read up on this first and come back with questions.
Thanks

Clutchcargo · 12-31-2007, 12:20 PM

Alright, if I double up the 2x8s, the floor will be stiff enough for ceramic tiles, tripling the 2x8s gets me to stone. Since this is only the foyer (approx 6'x12') adding extra 2x8s shouldn't be that big of a deal (famous last words).

So for the floor thickness:
1. original plank sub-floor = 3/4"
2. plywood underlayment = 3/4"
3. Ditra = 1/4"?
4. ceramic or stone = 1/2"

So it's about 2 1/4" above the joists. Does that sound correct? Do I need to add anything for the mortar?

If I go with a cement backer board, do I need the plywood underlayment or can I go directly over the plank subfloor?

What is your opinion of Ditra vs. a cement backer board?
TIA

Rehabber · 12-31-2007, 12:29 PM

You need the 3/4" plywood. If height is an issue, use ditra instead of backerboard.

Clutchcargo · 12-31-2007, 12:47 PM

I'm worried about the transition from the tile floor height to the old wood. There will be an 3/4" difference between the rooms, is that typical?

Rehabber · 12-31-2007, 01:13 PM

It is very common. just use a transition piece of the material of your choice. No one notices the transition on exterior doors, and the same thing happens between different surfaces. For a transition to a wood floor, I make a matching piece of wood cut at an angle the width of the opening, and finish it to match the wood floor.

ron schenker · 12-31-2007, 01:32 PM

Quote:

Originally Posted by Clutchcargo

I will be redoing my foyer floor with either slate or tile. I need to determine what the floor thickness will be for a new staircase that I'm putting up.
The floor is 2x8 joists 16" OC with a 12' span and a T&G plank subfloor. How much do I need to build it up to have a floor that is stiff enough for tile surface? Do I need to add a layer of 3/4" ply or will blocking between the joists
TIA

FYI...Slate, or any natural stone needs an L720 for a proper install

JazMan · 12-31-2007, 01:44 PM

Clutch,

Sistering will do the trick, even for slate. No need to triple. Add the 3/4" ply and then Ditra. Ditra adds 1/8" total.

Jaz.....................

Happy New Year!

Rehabber · 12-31-2007, 01:44 PM

Ron, in post #4 he said he would double sister joists which I believe would give him L905 plenty for stone.Jaz/ a single sister does not meet minimum deflecto for stone

ron schenker · 12-31-2007, 01:53 PM

Sorry, I missed the part about sistering. BTW, I've never seen triple sistering in my neck of the woods.

Rehabber · 12-31-2007, 02:01 PM

Ron, I hve done it twice, so much fun. 1 on each side oj joist. BTW, your info and knowledge have been very helpful.

Clutchcargo · 12-31-2007, 02:26 PM

Thanks everyone, tripling the joists it is.
Is Ditra the way to go or are there any arguments other than price toward using a cement backerboard? One of the DIY TV shows that I watch use Ditra on every project involving tile floors. I might be just falling for product placement marketing however.

Rehabber · 12-31-2007, 02:54 PM

I prefer backerboard over Ditra, but I have used backerboard for years. Ditra is a newer product, thart I have only used a few times, but I trust Schluter products. Choose yer weapons!

ron schenker · 12-31-2007, 06:12 PM

If $$$ is a concern use backerboard, Ditra is not cheap.

12-26-2007, 07:03 PM	#1
Clutchcargo I have gas! Join Date: Mar 2007 Location: Massachusetts Posts: 1,671	Tile and slate floor ??? I will be redoing my foyer floor with either slate or tile. I need to determine what the floor thickness will be for a new staircase that I'm putting up. The floor is 2x8 joists 16" OC with a 12' span and a T&G plank subfloor. How much do I need to build it up to have a floor that is stiff enough for tile surface? Do I need to add a layer of 3/4" ply or will blocking between the joists TIA __________________ I tear things down and build them up.

12-26-2007, 08:11 PM	#2
Rehabber Oldguy Join Date: Dec 2005 Location: Calif (the left coast) Posts: 498	Tile and slate floor ??? Your current floor does not meet L360 (the minimum required for tile)If you sister the existing joists with another 2x8 you will jump to L603 which is enough for tile, but still not enough for stone. You will need to put 3/4" plywood on top of all this, then yor backerboard of choice or Ditra. __________________ *If you think you can, or if you think you can't, you're probably right.* ASE certified master auto tech, Retired.

12-26-2007, 09:58 PM	#3
Clutchcargo I have gas! Join Date: Mar 2007 Location: Massachusetts Posts: 1,671	Tile and slate floor ??? L360/L603???...OK, back to the drawing board. I just realized I don't know enough to know what I don't know. I'll read up on this first and come back with questions. Thanks __________________ I tear things down and build them up.

12-31-2007, 12:29 PM	#5
Rehabber Oldguy Join Date: Dec 2005 Location: Calif (the left coast) Posts: 498	Tile and slate floor ??? You need the 3/4" plywood. If height is an issue, use ditra instead of backerboard. __________________ *If you think you can, or if you think you can't, you're probably right.* ASE certified master auto tech, Retired.

12-31-2007, 12:47 PM	#6
Clutchcargo I have gas! Join Date: Mar 2007 Location: Massachusetts Posts: 1,671	Tile and slate floor ??? I'm worried about the transition from the tile floor height to the old wood. There will be an 3/4" difference between the rooms, is that typical? __________________ I tear things down and build them up.

Tile and slate floor ???