To get it out of the way. Yes, I know I should get the relevent TCA publications. I mailed the check today, but that doesn’t help me this week.
The floor appears (at the heat vent) to be two sheets of 1/2″. The top sheet sure looks like particle board (but I didn’t pull much of the carpet back). The bottom sheet, seen clearly from the crawl is OSB.
The joists are 2×10 16″oc, spanning 12′. I doubt it matters but the beam supporting the 2×10’s is in the middle of the 8 foot length of the bathroom.
I’m assuming I need something between the particle board and the backer board, and that would be….??
Thanks,
Rich Beckman
Replies
Ya got me there Rich.
With 1/2 osb...then 1/2 partical......adding a lawyer of 1/2 inch backer would make for a plenty strong floor......but......the backer should be thinsetted onto the subsurface.
To me, there in lies your problem.....not sure how the thinset would bond with the partical.....and I'm guessing the moisture would swell it.
How much can ya raise things?
A layer of 1/2 ext ply ontop of the part board and under the backer would do nicely......but would that add to much?
Maybe the best line of thinking is one you were trying to avoid.....as in a little demo before the building. Get the partical board outta there.
You sure it's just regular partical board? Maybe there's some fancy water resistant version out there that I'm not familiar with?
Jeff
.......Sometimes on the toll road of life.....a handful of change is good.......
"Maybe there's some fancy water resistant version out there that I'm not familiar with?"
ROFLMAO!!
That's it! Marion is so cutting edge. Must be why the lumber yard always gives me those dumb stares when I talk about a product I learned about here! (for example...they carry Certainteed roofing shingles but had never heard of Roofer's Select underlayment...)
Demo the particle board??? Hadn't even considered that (and I don't wanna!).
I'm hearing that the floor is plenty thick enough, but the particle is bad. I'll be using a 1/4" backer board.
So my choice is pull the particle and replace with 1/2" ext ply, or put 1/2" ext ply on top. Still open to alternatives if anyone has one (just putting a price together).
Rich Beckman
If I follow you correctly, your floor has 2 layers, the top of which is particle board, and you want to lay ceramic, so what goes down first? The layer under the tile should be cement board. You lay it in thinset and can nail or screw it on though my neighbor the "professional!" tilesetter would murder me at the nail thought. Screws are the preferred option, about every 6". Tape (fiberglass) the joints and fill them (kind of like drywall, really, just not as purty. That being said, the finished height you want should help you gauge whether or not to peel the particle off. If you do, I would suggest adding a different subfloor so you don't permanantly thinset to the base. You never know, down the road someone might want to yank the tile out and carpet. Won't they be mad. You could use 1/4" ply for that. I don't think from your description that the joists are necessarily prone to letting things move, but if you are, sistering in more wood (or even laminating 3/4" ply to the outsides of all of them) wouldn't be unduly difficult, just time consuming. The bottom line, which I think you sound painfully aware of, is a solid base for the tile, since movement = cracks.
My vote goes for getting that particle board outta there. Once you get the TCA materials, you'll see a warning in there related to using particle board (and even OSB) as a substrate for tile. Because these products expand and contract with changes in moisture content, there is an increased chance of movement in the substrate which leads to tile or grout cracking. Additionally, the thinset manufacturers that recommend their products for use with any non-cementboard products usually specify exterior-grade ply, because of the problems mentioned about particle board sucking up the moisture in the thinset.
I assume this is just normal carpet that was tacked down? If it was glued down, then you absolutely should rip out the particle board as the adhesive residue may react with the thinset and prevent a good bond.
What area of the house is this floor in? If it gets any moisture at all, IMO the ideal substrate is 3/4" EGP with 1/2" backerboard screwed down and laminated to the ply with thinset. The important thing is to meet the minimum required substrate thickness of 1 1/8".
Andy
Rich
laticrete 9235 ( or similar ) then proceed as usual.
Any water based product placed on particle board will cause it to swell. I wouldn't do it, Rich. This includes backerboard and yes Laticrete 9235 which is water based latex. Here are some workarounds:
1. Remove the particle board and skin the floor with 1/2" plywood, then either 1/4" Hardi or Ditra. Check out Ditra at Schulter.com
2. Leave the particle board and skin the floor with 1/4" or 1/2" ply, then tile with the Hardi or Ditra.
3. Find a Sheet Membrane that is not applied with thinset (there are some peel and stick varities out there) and apply them, then just tile. I saw one the other day at tile shop but can not think of the name.
Hope this helps.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
Don't you want a waterproof layer somewhere? Either plastic or tar paper? The durarock (or equivalent) is not waterproof...and if there's kids or whatever, there's water.
Maybe I'm wrong, but I'd think if you are going to lay down another layer of sheating, you'd want the tar paper or whatever first, then the sheating, then thinset the backerboard onto that.
But I'm certainly NOT an expert...
Boris
It'd have to pretty crappy pb to swell with a coat of Laticrete. It's no different to giving it a coat of paint.
I note that this job has carpet on it? How many times has it been cleaned? Do you know what Carpet Cleaners use?
Hot Water and Steam
Here waterproofing with a Laticrete product or equivelent is S.O.P. and is mandatory.
regards
mark
http://www.quittintime.com
Edited 10/2/2002 4:54:52 PM ET by MARKCADIOLI
It'd have to pretty crappy pb to swell with a coat of Laticrete. It's no different to giving it a coat of paint.
Maybe so, but Laticrete's instructions specifically state that 9235 should NOT be bonded to particle board (or OSB for that matter). Laticrete, like every other mfg I've checked, specifices that the only acceptible wood substrate for their product is exterior-grade ply. Which means that, no matter the practical implications, the manufacturer won't warranty the product, and that means if something goes wrong, I have to go back and fix it free.
Check out:
Laticrete 9235 Installation Instructions
I've been looking around and haven't found any products that claim to be compatible directly over particleboard. If height issues aren't a problem I'd do what Boris said, otherwise in my opinion it has to come out.
My mistake...you are right. I chose Laticrete as an example as it was the only elastomeric I could find that would be available to you blokes. We use Superflex
http://www.norcros.com.au/pdfs/datasheets/dssuperflexpremixbathbalc.pdf
made by Norcross and put it down over PB
Regards
markhttp://www.quittintime.com
I hadn't heard of that product... thanks for the info. If it's available in the states, I'd like to try it out at some point.
Thanks for all of the input. I have decided that the particle board comes up.
Mark,
The Super Flex sounds very interesting, but I couldn't find anything at the web site to indicate it is available in the states. Also, under "Application Range" it does list particleboard, but it qualifies that with "wet area grade, internally only (special preparation is required - contact Norcros)"
I would be surprised if the particle board is "wet area grade".
Thanks again. This is an amazing place, isn't it!
Rich Beckman
I'd wait to see the condition of the OSB. If good, seal it with a couple coats of polyurethyene, then Ditra, then thinset the cement board. The spelling on that site was wrong tho'. it's
http://schluter.com/ .
Excellence is its own reward!
Yea piffin thats what I was gonna suggest seal the PB first but be sure to use long enough screws to get a good bite on the OSB when putting down the backerboard. The PB dont hold either screws or nails well. Darkworksite4: When the job is to small for everyone else, Its just about right for me"
Of course the more excellent responce is to replace the OSB but I just don't see it as necesary unless it is already going bad..
Excellence is its own reward!
You talking PB or OSB? I'd still say the PB got to go......
Jeff.......Sometimes on the toll road of life.....a handful of change is good.......
Hmmmm....
Somehow, I was thinking OSB all the way through this thread. That never was made clear after I read back thru' again. I kept wondering too about why did they use two plies of OSB?
OK, PB has to come up..
Excellence is its own reward!
now I feel better!
Jeff.......Sometimes on the toll road of life.....a handful of change is good.......