Which underlayment for porcelain tiled floor?

[cgv69]

Sorry this isn't directly garage related but hopefully you guys will be nice enough to share your opinions/experience on this matter anyway?

I want to install a tile floor in a 9'x6' (roughly) laundry room. Plan to use porcelain tiles. Need to verify but floor seems pretty level. Subfloor is T&G OSB over engineered I beams 16" OC (need to verify that too). Not worried about matching any other pre-existing floor height of the adjoining hallway but if I can get the whole thing to line up with 3/4" HW that would be perfect.

What underlayment do you guys prefer/recommend... Generic cement board, hardibacker, Ditra and Densshield are some of the options I've been looking at?

For such a small room, I'm not that worried about cost or ease of installation. What I am focused on is ending up with a solid, level (so I can avoid cracked tiles and grout lines later on) and reasonably waterproof just in case.

 

[Siteman25]

You might want to talk with someone local who has a little more knowledge than I, but you may need to stiffen up the floor it the joists are 16" O.C. I believe rule of thumb when using tile is to space joists at 12" O.C. to keep the floor stiff enough to keep the grout lines from cracking. The cement board may be enough to stiffen it but I'm not sure.

 

[rust buster]

Although Ditra seems to be catching on, I'm old school and prefer Durock...just be prepared to drive a **** ton of screws (every 8"). Then use Flexbond and you shouldn't have a problem with cracked grout.

 

[cgv69]

I meant to type 12" OC, not 16" but again, I need to verify that.

From the reading I've done, each different type of underlayment has it's own requirements. I've seen the specs for Hardibacker and Ditra and I can't remember what they are off the top of my head (hardi was something like 16"OC with "X" thickness subflooring and Ditra was 19.5" OC with "X" thickness subflooring IIRC?) but I'm pretty sure my floor is within spec for either?

 

[GTO]

1/4" OR 1/2" Hardie board would be fine

 

[engineer2]

16" OC is fine with 3/4" plywood or OSB. Subfloor is nailed down (plus glued down in newer homes). I always run construction screws into the floor between each nail.

If there is no bounce to the floor, you should be OK. I've seen the older-type gang-nailed joists made of 2x4's get bouncy when they get old. You can also install bridging between joists for added strength.

I have had zero issues using Ditra.

Keep in mind tile projects can expand into surrounding areas if the wife likes it.

 

[jav]

Not an expert but I was told you need at least 1-1/4" thick structural subfloor to avoid flexure under tile. I always took this to mean 3/4" t&g plywood/osb plus an additional 1/2 plywood appropriately fastened to that. You can go over plywood with a good latex modified thin set (I wouldn't skimp on this part).

I'm not sure if cement board qualifies as a stiffener??

 

[ddurrett896]

Ditra because it's not only good, but light and easy to cut!

 

[jp828108]

Had a buddy (he lays flooring for a living) do my basement and entryway landing. Basement is obviously a concrete slab. So tile went right over that. Entryway is joists 16 on center. It had 3/4, 1/8 (i think), and some type of vinyl. Had a bit of swelling from water intrusion through the front door at some point..... Not major, but I opted to have it replaced. no way I wanted to spend the money and not do it right. His preference was ditra so that is what I went with. He replaced sub floor with 3/4 inch T&G glued and screwed down. then put the Ditra and tile down. It has been in for around 3 or 4 months. No issues with cracking or anything yet, and he wasn't concerned that it ever would give me issues.

 

[nick2010tundra]

1 1/4 " plywood is the old school tried and true. Ditra is a stop gap product made to allow the tile to move as a whole, when your subfloor is not strong enough. So the question comes down too. " Do you wanna do it right or do you wanna use a product to make it right". Also I think a lot of contractors like to use ditra because they can charge mark-up on the product ( which around here a sq ft of ditra is more that the tile ), plus its easier to work with. Like peel and stick

 

[larry4406]

My foyers and kitchens in my personal houses I used 3/8" thick AC plywood over my 3/4" subfloor. My joists are 16" o/c with short spans. Glued and screwed the AC plywood. After thinset, tile plains out perfect with my 3/4 sand on site hardwood and zero threshold or reducers to trip over. Looks nice. Other thickness underlayments will result in height disparity. No cracks after 15 years last house and 3 years this house.

On new home construction, the firm I work with chokes joists to 12"o/c for tile. In our bathrooms we use a 1" mudset floor. On our foyers and kitchens we use 1/2" durock. When marble foyers are done we change the OSB sub floor to hem-fir plywood.

 

[cgv69]

Thanks for the info guys. Between your replies and the research I've been doing, I think I may just skip the tile for now and just go with one of those water proof laminates for the time being.

I'm the type that if I'm going to do something, I'm going to do it right and I'm running out of time to do this right before moving in which is the goal

Laminate will be fine for now and I can always come back and do the tile later

 

[larry4406]

Thanks for the info guys. Between your replies and the research I've been doing, I think I may just skip the tile for now and just go with one of those water proof laminates for the time being.

I'm the type that if I'm going to do something, I'm going to do it right and I'm running out of time to do this right before moving in which is the goal

Laminate will be fine for now and I can always come back and do the tile later

I can understand that. Unfortunately for me, temporary seems to become permanent once it's done. Thus why I still have vinyl tile in my kitchen and master bath 3 years after move in....

 

[F350]

I did a bathroom reno so many years ago, maybe a decade ago, when 12x12" tiles were becoming a fad. I used Hardiebacker after pouring a self-leveling underlayment because the subfloor was cheap thin plywood. Stout floor, no cracking or popped grout whatsoever. It was my first time doing this type of floor. I simply followed instructions.

Just do it right once. Hell, do without until you can knock it out. Took me months to finish the bathroom cos I was either busy or lazy and refused to use vinyl peel-em-and-stick-em flooring.

 

[theoldwizard1]

I meant to type 12" OC, not 16" but again, I need to verify that.

12" would be unusual.

Modern codes allow a lot more "flex" in a subfloor which of course would crack the grout. You want something really solid, and make sure you use plenty of screws into the joists,

 

[James-W]

Thanks for the info guys. Between your replies and the research I've been doing, I think I may just skip the tile for now and just go with one of those water proof laminates for the time being.

I'm the type that if I'm going to do something, I'm going to do it right and I'm running out of time to do this right before moving in which is the goal

Laminate will be fine for now and I can always come back and do the tile later.

Some of the laminates are really good, and then there are some not so good. If you spend a bit more money and get a really good laminate, it will look great and wear VERY well. You just may find out you like the laminate and you will forget about doing the tile.

 

[cgv69]

I can understand that. Unfortunately for me, temporary seems to become permanent once it's done. Thus why I still have vinyl tile in my kitchen and master bath 3 years after move in....

LOL - Me too so I'm usually hesitant too about "temporary" fixes but in this case, while I do think tile would be a little nicer, it is just a laundry room and the new laminates should be fine?

I figure it this way, if I go with the Laminate and it ends up being permanent... great, that means it's held up and looks good so I've saved time and money going that way. If not, it will at least buy me some time and I'll only be out ~$150 and it will be easy to pull up later.

12" would be unusual.

Modern codes allow a lot more "flex" in a subfloor which of course would crack the grout. You want something really solid, and make sure you use plenty of screws into the joists,

I haven't moved in yet but will be stopping by the house tonight and I will be checking/verifying all of that.

Some of the laminates are really good, and then there are some not so good. If you spend a bit more money and get a really good laminate, it will look great and wear VERY well. You just may find out you like the laminate and you will forget about doing the tile.

I did Pergo in the kitchen of my first house 20+ years ago and hated it but from what I've seen, the new Laminates are much better then they used to be? I wouldn't even be considering it as an option otherwise.

 

[James-W]

I did Pergo in the kitchen of my first house 20+ years ago and hated it but from what I've seen, the new Laminates are much better then they used to be? I wouldn't even be considering it as an option otherwise.

I helped a buddy put down a laminate in his computer room (home office) a couple years or so ago. He had purchased the flooring from Lumber Liquidators and it is some really heavy duty stuff. That floor still looks great, just like the day we put it down.

 

[Radix2]

The new vinyl locking strip floors are really nice and a good choice for a laundry room.

Otherwise ditra under the tile.

 

[ard]

I didnt see anyone say mortar bed....Ive done it in bathrooms, mudroom, laundry room. 3/4" Sturdifloor on TJIs @16"...then old fashioned mortar bed.

Is this inferior these days???

 

[Zeke]

I didnt see anyone say mortar bed....Ive done it in bathrooms, mudroom, laundry room. 3/4" Sturdifloor on TJIs @16"...then old fashioned mortar bed.

Is this inferior these days???

Not inferior but there are a lot more choices than when we had what we call old fashioned now.

Personally, I prefer to use 1/2" backer over the subfloor laid in a bed of thinset. Be sure to run joints anywhere but over an existing joint. Last job I did is now 2 years old and not a trace of a crack anywhere. It's 1/2" backer over 3/4 T&G subfloor and set in the thinset. I nail it off first in order to get it down and into the thinset and then go back and screw it off 8" OC before anything gets too hard. Check for hollows with a rubber hammer.