Help Please ! Tile - Contractor Talk - Professional Construction and Remodeling Forum

mxim · 12-07-2007, 10:05 AM

need some help guys. i am a roofer but am going to tile MY OWN kitchen. question is this. i have 3/4 inch ply wood as my sub floor. so all i have to do is lay 1/2 inch backerboard on top of the 3/4 inch ply wood?
the backerboard is layed using thin set,then taped and screwed or nailed?
thanks guys

reveivl · 12-07-2007, 10:12 AM

You first need to know if the structure is suitable for tile. Joist size, span, distance apart? Likely you will need another layer of ply, then thinset and backerboard. You can use 1/4" if height is an issue. Use mesh tape and do it as you tile so you don't get a hump under the tile at that point.

Home Serve · 12-07-2007, 06:48 PM

I'd strongly recommend using Ditra under your tile if you want a good installation. It is easy to put down. Can get it at most H.D. stores but do not get advice there. There are several good tile forums even where you can determine if your floor joists offer enough support by putting your info into and it will show you deflection.
John Bridge something, I believe if you search will find it.
Dave C

mxim · 12-07-2007, 08:57 PM

so again,if i have 3/4 inch plywood as a sub floor,i just add 1/2 inch backer board and thats enough? or i ass the ditra over the backboard?

Home Serve · 12-07-2007, 09:05 PM

No, Ditra is all that you need and it is much better than backerboard for the long term and easier to use. Here are two sites. on John Bridge click "defleco" button at top of page and enter your span, joist size... It will tell you if adequate. A little bit of homework saves a lot o bit o headache with tile!
Ditra info on sites and comes with booklet, nothing difficult.
http://www.johnbridge.com/vbulletin/....php?forumid=1

http://forums.jlconline.com/forums/index.php

Dave C

reveivl · 12-08-2007, 02:14 AM

Quote:

Originally Posted by mxim

so again,if i have 3/4 inch plywood as a sub floor,i just add 1/2 inch backer board and thats enough? or i ass the ditra over the backboard?

No, likely not. You will probably require more plywood to take the flex out between the joists. Remember, the backer board adds nothing in the way of structure, it is there to isolate the tile from the wood. Ditra does the same thing as the backer, you don't use them both.

Floordude · 12-08-2007, 08:17 AM

Have not done much mortar & tile in the last 7 years, or is that 8 years now... Wow time flies, but any way, I seem to remember a requirement of 1-1/8" plywood subfloor, before CBU panels.

Jerry T · 12-08-2007, 03:40 PM

If your joists are 16" OC and not under-sized or over-spanned the 3/4" plywood is Ok if it's a T&G.

If you use a cement backer board the 1/4" thick is sufficient. I agree that Ditra is better, but either one will do the job. Both get imbedded in thinset. CBU's are set into dry-set wetbeds and Ditra is installed over a modified thinset wetbed.

mxim · 12-08-2007, 04:30 PM

so 3/4 inch plywood as sub floor and just add ditra?
or do i add another 1/2 inch of ply wood for a total of 1 1/4 inch plywood and then add ditra?
thanks fella's

Home Serve · 12-08-2007, 10:14 PM

If your deflection meets the standards on the John Bridge website I sent in previous message you can put the ditra down according to instructions right over the 3/4" plywood.
There is a lot of information on tile floors on those websites.
Dave C

Jerry T · 12-09-2007, 07:45 AM

More plywood is always better if you can stand the added height.

mxim · 12-09-2007, 10:12 AM

that ditra stuff looks cool. just went to the website.
for showers,i would use standard backerboard and apply ditra over the backerboard?
some guys use backerboard and then just use felt paper.

Home Serve · 12-09-2007, 11:08 AM

Showers are a whole different ball game. I've do showers but spent hours of homework and asking questions at a local specialty tile shop before I attempted one. The web sites I posted before are a good place to start.
Dave C

Jerry T · 12-10-2007, 05:27 AM

No ditra in showers, use the Kerdi.

mxim · 12-10-2007, 08:46 AM

why not ditra jerry?
can we use traditional backerboard and then cover it with 15lb felt paper?

Home Serve · 12-10-2007, 07:20 PM

Quote:

Originally Posted by mxim

that ditra stuff looks cool. just went to the website.
for showers,i would use standard backerboard and apply ditra over the backerboard?
some guys use backerboard and then just use felt paper.

I'll tell you what new guy, if you want to create a nightmare for yourself and your customer tile that shower for them without knowing what the H*LL you are doing.

Then you'll get a little experience to demo it out and do it again!

Jerry T · 12-11-2007, 06:10 AM

Quote:

Originally Posted by mxim

why not ditra jerry?
can we use traditional backerboard and then cover it with 15lb felt paper?

The felt or poly goes behind the backer board if you are tiling directly to the backer board. Then purpose of that is a moisture barrier and to shed water down into the pan liner.

kgphoto · 12-11-2007, 03:18 PM

mxim,

Based on your responses you have ignored the best advice given. Go to Johnbridge.com and use the deflecto calculator properly and that will let you know whether or not your floor will work with the plywood you already have or whether you need more.

Then go the "liberry" section and read up on shower construction. That will give you a better framework to come up with questions.