Flooring question (installing Durock 1/2" concrete board)

[Luke'sScreenName]

3/4" is too much at the perimeter. Do 1/2 at most. I agree to tape the seams. A few extra steps is easy compaired to ripping the whole thing out and re-laying it. 24x24 tiles can be a real pain to install if the room is not perfectly flat and square.

 

[KevT]

Is the sub floor flat? Mortar does not stick to plywood and depending on what mixture you use can cause premature rot ( hence why you use PT lumber on concrete) If you need a leveler use a vinyl.

What is the what ever size? The sheet are 3x5, turn the sheets 90 degrees and use a 15" ripper. I agree I like Hardee better but both also come in 4x8 sheets too.

Don't scrimp with the backer or it will show down the road when tiles crack or grout pops from movement. 40% waste is not waste for a job well done

 

[Richard]

Sub floor is flat (though it might have some small variations that I can't see)

The other size of the room is something like six/seven feet.

I've already got the 1/2" durrock laying by my door so that's the road I'm on. Getting ready to go measure the closet and start making some dust! (cutting to fit)

 

[JimRB]

Latex modified thin-set adheres well on plywood. I preferred using thin-set over mastic. It is easier to clean off clothes, hands and tile. It was also ready for grout the next day while mastic might be mushy for days. I sanded and vacuumed the plywood floors before spreading the thin-set. I never had any warranty issues back when I set tile. https://www.usg.com/content/dam/USG...ssets/durock-cement-board-submittal-CB399.pdf

 

[GPintheMitten]

I would never use mastic in a bathroom. Use a mortar mix to adhere tile. I bought.my tile at a tile store, not a big box store and received some good advice regarding the mortar product.
Don't try and get by with 6' in a 6' 3" room. Look at different ways to orient the backer board stock you have. Maybe a 5' and a 3' ; cut the 5' to 3' 3"?. Draw it out on paper if it helps.

Tape your seems with fiberglass and mortar.

Good luck.

 

[GLyford]

I believe the Hardi instructions says to use unmodified under it, then modified to lay the tile over it. If your floor is flat, the directions say you can use the 1/4" stuff under floor tile, but I used 1/2" so there'd be no chance of the screws hitting the under floor heat tubes, per my HVAC guy.

While it's true that people don't walk against the walls so you wouldn't need support for that, what about furniture? Chair or table feet or plywood cabinet sides may end up bearing weight in that space. Would that be enough to break a tile? Don't know. You could fill the space with thinset, I suppose. No idea if that would be enough to get away with or not. If the arrangement of the room is such that you will never have furniture against that wall, I'd be tempted to say go for it...but then, I'm a hack.

 

[Richard]

This is a bathroom so there won't be any furniture in there .....other than.... a chair of sorts...

That said, I might indeed change the rotation of the floor. Changing the rotation will allow for a better coverage of a specific seam (that otherwise falls pretty close to the edge if orientated the other direction)

 

[mecan]

Good luck, I used hardi and durarock when I did my bathroom and kitchen. Prefer the hardi, but had someone run out and grab a couple more sheets and they brought back durarock. Personally prefer the square head screws over phillips, and a driver over a drill. Make sure to sink the heads a little below the board. A 2nd person to back butter the big tiles and hand them to you helps alot. They become heavy fast.

 

[Steppenwolfe]

Do you want a professional opinion?

Thinset over the 3/4 " subfloor with 1/4" notched trowell
Install the 1/2" cement board onto the fresh Thinset and screw down with stainless steel 1 1/4" screws 6" spacing on edges and 8" in the field
Install all joints tight and leave 1/4" gap at walls
Next day, tape and float all joints with Thinset , let dry 24 hours
Now you are ready to lay your new ceramic flooring

 

[Pixguy]

Informative thread. Has anyone installed heated mesh from Warmly yours under your tile?