Flooring Tile - Sub-Floor terminology- HELP!!

I hope someone can please help! I am remoldeling my bathroom. Everything is done except the floor. I have chosen to put ceramic tile. There is vinyl tiles there now. When I started to remove the old tile I noticed the floor underneath is plywood. The guy at the store told me if it was plywood it would cost me several hundreds of more $$$. I have tried to do some research and have only become confused. What I need to know is, what do I do? Can put the tile on the plywood itself? And what is thinset? and Backerboard? and...please anyone who is willing to help a lady out I'd apprieciate your comments.

Thanks
Starry-eyes :confused: :rolleyes: :p

you can install tile over plywood if it is strong enough..this might mean that you need two layers ..In many cases people choose to use one layer of ply wood and the second layer backerboard .Backerboard is made out of many different things but normaly it is a cement board.Thin set is the adhesive or "glue" used to bond the tile to the board be it wood or cement. I would suggest that you either start reading post on this forum or buy a good book on setting tile.If you need some reccomendations fire me a note or post.

:D thank you so much for the info. Believe it or not I have laid tile before...I just have never done the preparations to the floor...it had always been done already. Thanks again!

"thick enough" = at least 1 1/4" of subflooring to keep it stiff enough to accept tile and grout. That's why backerboard (like wonderboard, hardiboard, durrock) are so useful, because the floor sheeting is generally ~ 3/4", and the backerboard is 1/2". 3/4" + 1/2" = 1 1/4".

I wouldn't recomend tiling on plywood. Since plywood can soak up moisture and warp I'd depend on a backerboard surface to set the tile. It adds quite a bit of stiffness, and isn't so easily damaged by water if unprotected. If you have a subfloor that is plenty thick enough go get the 1/4" backerboard and set that down. Otherwise get the 1/2". Bear in mind that you can only use 1/2" on the walls. You can't use 1/4" there...

To install this stuff correctly (since it generally comes in 3x5 sheets) you need to use a level and a pencil, or a chalk line to lay out where the panels will go on your floor before hand. Lay out the full panels first, and then mark out where the smaller pieces go. Important: always stagger the seams. Never end up with the corners of four different pieces to join in the same spot.

Cut the stuff using a scoring knife and a drywall Tee square you can get at the store when you buy the board. Clean up the edges with a construction knife and the back of a hammer. Lay out the cut pieces before hand before you thinset them in place. After making sure they all fit take them back up, clean the floor, and prepare to thinset and screw them down.

Make sure you get plenty of screws. You need to use the special rock-on screws that have double small and large threads, with the teeth on the undersides of the head. They don't rust, and they bite into the board and won't back out. Using drywall screws is not a good idea. They'll rust, and they'll back out or break. You need to screw the board every 4-6", and you have to stay 2" away from the edges unless hanging on the wall...

Get fortified thinset mortar when you buy your board. It generally coves about 75 sq. ft. Fortified means its mixed with a strengthening agent like acrylic. Use a "paddle" to mix the thinset up in a small cement mixing tub or a 5 gallon bucket. Follow the directions, but you basically want it light and easy to manage. It shouldn't be shiny. If it is then there's too much water in it.

Use a 1/4" notch trowel to spread the mud out, and drag it at a 45* angle to make clean 1/4" rows. Evenly spread it so excess doesn't creep up between the boards. Only mud enough to cover each piece. You want to screw it down before moving to the next board. Set your first board (farthest corner) and screw it down. Work your way across the room to the other side. Keep 1/8" of space between panels so you can thinset the seams later (you can use nails on their ends to do this).

Once that's done I generally let it dry before mudding the seams. For every seam that has been cut (that isn't completely wrapped with mesh like the two long factory edges of the material) you'll need to use some fiber mesh tape. Use a margin trowel to get mud into the seams and spread it evenly. Then lay your mesh tape along the seam in the mud pressing it into place with your margin trowel. Smooth out and add mud where necessary until you get a continuous mudded seam that's flat. Usually you can take this opportunity to smooth out any dips and inconsistencies using the mud and a finishing trowel.

Once that's dry make sure your floor is flat and you're ready to tile -AND you know your floor is ready to take tile versus guessing and hoping the tile and grout doesn't crack.