putting tile in the bathroom, part II

[bob]

carpet installers are here and ripping up old stuff. flooring is particle board thick enough to be very rigid

can i put durorock membrane on this for tile?

[Joe]

Particle board in a wet environment like a bathroom is far from ideal. Rip it out and ask a pro what would be better. Or band-aid it like you suggested and live with the inevitable do-over. Given your situation I would simply Durock over plywood on the joists and not worry about it for years. That and a Schlutter membrane should be very long lasting for tile work in a bath.

Joe.

[bob]

right now there's tile in the bathroom...ugly stuff which is why i want to get rid of it. but it looks like the floor's stable enough for tile. want to make sure it stays that way!

thanks much

[dadiOH]

Stable doesn't count. Expanding to 2x or more its thickness when it gets wet does.

[Colbyt]

I learned my lesson about particle board in kitchens and baths about 30 years ago.

You can rip it out and do it right or learn what I learned the same hard way I did.

The choice is completely yours. :)

[bob]

the bathroom already has particle board...

[aemeijers]

Not saying particle board is correct solution. But I will say, that for several decades after mud-bed died out, and before backer board became common, particle board underlayment sealed with I-don't-remember, covered with grouted tiles held down by mastic, was quite common. Same for under kitchen vinyl floors, but the PB wasn't sealed, since it wasn't considered a 'wet' usage. Even in modern times, I've only seen backer board in a kitchen if they were planning to put down heavy-but-porous clay tile.

[Robert Green]

When I worked construction a long, long time ago the old pros called it "chip board" but it sounded more like "shit board." I know it's used in bathrooms and other "it's going to get wet sooner or later" places and

*should* present no problems with a waterproof membrane . . . Still, I would pull it if you are in there anyway. There's nothing cheaper than chip board because almost everything else is better. (-: I can't count all the places where I've seen sagged chip board.

-- Bobby G.

[mm]

Isn't chip board the stuff made with chips, some 4" long, and particle board the stuff made with particles, pieces no more than 3/8" long. The latter is used for cheap furniture and comes in 4x8 sheets too, but chip board is a lot stronger. (but that doesn't mean it is good for for wet places like bathroom floors.)

but it sounded more like "shit board." I know it's used in

[Robert Green]

That sounds right, but I'm working off a memory from nineteen seventy something when it was fairly new and held in great contempt by carpenters used to working with plywood. Chip/shit board seemed to be their name for anything that held bits of wood connected by glue. Additionally, these old gruffsters would NEVER use a four syllable word like "particle board" when there was a two syllable word like "chip board" available!

-- Bobby G.

[mm]

I hold it in contempt too. When I was in college they replaced the radiators in George Williams College, now a dorm for U of C, and htey forgot to put one radiator back. When they turned the steam back on, tThe desk and the wardrobe swelled to 3 times and the guy whose room it was couldn't get them open to get his clothes, etc.

They are equivalent to the meat they sell which they call "chopped, flaked, and pressed". That is, it's the meat they scrape off the knife when they are cutting real meat for other people. (and that's the good part.)

OTOH, it's a shame to waste all that junk if it can be used.

[aemeijers]

Particle board has its place. It is fine as underlayment in a living room or bedroom if you aren't putting down a real hardwood floor, and SWMBO insists on W/W carpet anyway. Dense, very flat, gives floor a solid feel, and holds up okay if you know it will NEVER get wet. And it can be an okay middle layer between 2 or 4 plies of real wood, if it is the high-pressure stuff. (Back in the day, that is what most speaker boxes- remember walnut floor speakers?- were made of.)

I really hate seeing people using it as a structural member, though- mainly in crap furniture, kitchen cabinets, or premade faux-woodgrain shelving boards. Doesn't hold connectors worth a damn- even those barrel inserts like the kit furniture uses in corners, and can't hold any weight over even a short unsupported span. I've even seen people use it for stair treads, which I think should be a code violation.

[krw]

"Chip Board" is also known as OSB (Oriented Strand Board). Particle board is an entirely different animal. Neither are worth a damn around water, though.

[mm]

I'm trying to cut down on what I buy from China.

[gpsman]

To be fair, we don't know if he should have learned setting tile isn't as easy as it looks on TV.

A bathroom floor is not typically a "wet" environment, but it doesn't matter what wood you put under tile; if it gets wet it's going to swell and pffft.

But, it won't get wet if the floor is sound and has the structural rigidity to maintain the excellent seal of a competent tile job... that you're probably not going to get anyway.

$400/1.33 sq. ft. seems a tad steep for 300-sq. ft. of "light duty" membrane (you're going to use how much of?), and I'm not crazy about it being 3' wide, either, when 6' would provide a seamless application in most residential baths.

But, a membrane isn't a "pan". If water penetrates the tile, it's most likely to occur at an edge, of the tub, if there is one. If there's enough water to flood the floor, it's going to run out the door.

They're doing marvelous things with new materials, but I think that stuff is a gimmick.

100% of bathroom floor leaks are due to the shower leaking onto the floor.* -----

- gpsman

*Estimate.

[krw]

I doubt it.

[jamesgangnc]

For my 2c to the original ? I would put 1/2" concrete or fiber backer on top of your osb subfloor. Use motar and screws every 6 to 8 inches. Lowes has the screws right next to the backer in the tile department. Do not use the 1/4" backer, use the 1/2". You don't need "fancy" motar either. The ordinary gray stuff that is under $10 a bag will do just fine for putting down the backer board. Try to use the backer board with as few cuts as possible. Do not piece together bits of backer board to save $10. As you plan the backer board avoid having the seam between two pieces of backer board coincide with any seams on the subfloor osb. Also try to not have a tile seam over a backer board seam. This takes a little extra planning. If you have left over screws then put them in as well. Stay off it for at least a day after you put the backer board down. Tile is all about the prep work. Actually putting the tile it's self down is no big deal. This has worked well for me many times.

Water will eventually damage any flooring if it has enough time. Osb will swell. Plywood will swell. Joists will swell. I'm betting your house is not made of metal. If any of this happens the tile will crack, come up, and grout break out. Do not caulk around toilets as this is a common spot to leak and caiulk will simply trap the water under the toilet where you can't see it. Tubs and shower bases present a problem. If you don't caulk then spilt water can get under them. If you do caulk then you are less likely to see a leak that develops under either of these. It's a no win. Pay attention to your house. If the bath is on a second floor then be aware of the ceiling below it. If the bath is on a ground floor then it's not bad idea to take the occasional look around when some curcumstance causes you to be in the crawl space.