Situation-
Adding new basement bath. No existing water issues, floor was poured in 07 seems stable/level. Concrete floor has been built up with 1.5″ sleepers 24″OC with 1.5″ rigid foam. On top of that is 3/4″ AdvanTech t&g glued and screwed to the sleepers.
Would like to install ceramic tile floor but have concerns about the subfloor/underlayment and the 24″ span. I’m getting mixed suggestions from tile suppliers. Some say no way will it work others recommend various underlayment combinations with a wide variety of suggestions.
Any help?
Thanks
Replies
Well, since no one else has chimed in: 3/4 at 24" seems pretty light. You definitely need to add stiffness somehow.
What size tile are you considering?
I'm open re tile size-probably something 12" and smaller. Made some calls to local suppliers and installers-suggestions are
add 3/8 ply and Detra
add 1/2" cement board and tile
add 1/2" cement board and Detra
add another layer of 3/4" and Detra
use lanolium
Thanks
skippy
I ask a similar question early last year concerning 3/4" Advantec on 19.2" center floor trusses. Not sure if it was here or at the "classic" site. 19.2" o.c. floor trusses only have 15 1/2" free span between the truss cords, and they are 3 1/2" wide. On advice from many and a little digging at some tile web site, I ended up using 1 1/8" Advantec on the whole house.
In your case I would add the second layer of 3/4" Advantec with glue and screws. Your sleepers are flat I assume so your free span is closer to 20 1/2" and with 1 1/2" rigid foam under that span of two layer, you should be ok.
3/4 Advantech at 24" MIGHT not be light.........
at least it's better than other brands of subfloor at that distance. However, what about a vapor barrier in that mix?
Regarding avantech-have you contacted them and asked?
In theory there wouild not be any downward compression with the flush to the sleepers foam below.
Can't say either way as I have no experience with that sandwich, except the spread of the furring is wide, no vapor barrier mentioned and the positive is the use of the superior subfloor. If you're laying the tile, you eat the mistake. If someone else is doing the tile, you pretty much have to follow their advice to even come close to any install warranty issues.
best of luck.
underlayment
I naively took the advice of the guy who poured the floor and did not use a vapor barrier under the slab-I know better now.
I did not thnk of contacting AdvanTech re tile installation not sure they'd have anything to say re what goes on top of their product.
I mention contacting them because-
We all would like to have at least an inch of subfloor (not cement board) under cement board when the joists are rated properly and the centering is 16". They rate their floor according to the centers-with it probably being "ok" for subfloor use on 24" with say carpet, vinyl, or hardwood..................I say probably because I have no spec sheet in front of me. Around here when subflooring over truss joists at 2' centers, you're looking at at least 1" material........but that's not advantech. And the trusses are often 3-1/2" wide-so the span is less than your sleepers.
Caught in your situation I would opt for thicker subfloor adding at least 1/2" plywood, glued and screwed to what you have now. Use a thinset compatible with plywood underlay.
But that's not over advantech-Have never worked over that product but am impressed by their demo's and claims.
From what I read in an older TCA handbook-OSB subfloor, 24" spacing joists, need an underlay of 5/8's ply laid long grain across joist direction (sleepers). No underlay fasteners to penetrate joists (sleepers). Gap underlay ply joinsts. So evidently that option is one that will work.
I suggest you contact advantech to see it they're forthcoming in information, take a look at the Tile Council of America's handbook and apply that to your situation. I'm no tile guy. Just a dumb carpenter that has had to modify guidelines to meet conditions and then put their name on it. Luckily the modifications have worked.
Best of luck.
Thanks-I'll see what AdvanTech has to say.
Great
Bring back the news. It might help us when we get in a like situation. Thanks.
You need to do a deflection test to be sure....
I dont think anyone has suggested this yet but all the engineers in the world can't argue with the testing of the floor.
The most common problem I run into is someone over the holoidays with a roomfull of peole - usually th kitchen, while the proud homeowners are shoing off thier concrete counter topped island and new ceramic tile.
The only way to be certain is to calculate the total load, load the floor at the center of the span and measure the deflection. For a couple of huindred dollars you will know what the floor can withstand.
This is the most critical step in determining tile and whay its not done more, I will never know.
Anyway I hope that helps you form a complete opinion on the topic before you just cross your fingers and hope for the best.
Regards,
Sam Beagle
Beagle's Interiors
Beaverton, Oregon
Sam
Welcome to Breaktime.
In the original posters question he's dealing with 1-1/2" sleepers 24"oc on concrete with 1-1/2" foam between. The deflection he's concerned about is the subfloor/underlayment, not the joists. Advantech we know is a stronger product than regular osb and therein lies the question-stronger, but strong enough?