Ok, so I've got a 5/8" subfloor and I'm going with 1/4" plywood,
thinset, 1/4" backerboard, thinset then tiles.
Should I bring the bathtub flush with the backerboard using 1/4"
Also, what type of screws are used to hold down backerboard? And do I
need a hammer drill for the 1/4"?
Yes. Flush to the tub. So why not just use 1/2" b.board to make you
flush to the tub, or 2 layers of the 1/4" b.baord? I've used screws but
I prefer using galvanized roofing nails rather than screws. They don't
tend to protrude like screw heads. Screws for b.board are just a hassle
and not necessary. Hardibacker Mfg. advises you can use either or. I
also like to apply tile mastic to the back of the b.board prior to
laying it down.
If you insist on the screws, use a cordless screw driver and the
recommended screws for the b.board that are available at the depot or
lowes. Trust me, use the galv. roofing nails of the proper length with
Why not just use 1/2" backerboard? It would be easier and make for a
stiffer floor. You are right to use thinset and screws. You do not
need a hammer drill. Just get the "Backer-On" screws at your local
home center. They are self-drilling. If you have a cordless drill
with an adjustable torque setting, you can use that to control the
depth of countersink when you drive the screws. You want to make sure
they do not protrude from the backerboard.
Use thinset for floor tiles. Mastic is not strong enough.
Thanks again for the replies G and John...I don't know if the local
Home Depot carries Hardibacker but I'll check. Believe it or not, the
"tiling isle" only stocks 1/4" backerboard...I found 1/2" in the
Would running 1/2" backerboard under the tub lead to a sturdier tub as
well? Or just go with the 1/2" plywood. Whatever the case, it looks
like thinset over the subfloor, backerboard, thinset and tiles... :-).
I dug up the following on fasteners: Minimum 1-1/4" long
corrosion-resistant roofing nails (OR) minimum 1-1/4" No. 8 by 0.323"
head diameter ribbed counter sinking head, corrosion-resistant screws.
I like the idea of nails for obvious reasons.
The installation link on the Hardibacker website isn't loading for
some reason: http://www.jameshardieeu.com/spec.html
Can you tell it's my first time tiling a floor?
Assuming your tub is a fiberglass unit, the Hardibacker under the tub
would be fine, but not necessary. However, you should put something
under the tub when you install it to stiffen up its floor. I've seen
plaster or drywall compound used, but these tend to shrink. They make
a special mortar product just for this purpose that sets fast and
doesn't shrink. I forget what it's called (underlayment cement?), but
you just mix a 25lb bag of the powder with water and trowel out a good
sized blob under the center of the tub unit. When you set the tub onto
the mortar, it conforms to the bottom of the tub and really stiffens it
up once it sets.
Given a choice, I use screws over nails every time. They tend to hold
better, are easier for me to set to the correct depth, and are more
easily removed if necessary (though I realize this may not be a
consideration in your situation).
Don't worry about this being your first tile floor. It's not that hard
to do. Just take your time laying them out and cutting. As long as
you have a sturdy subfloor and underlayment, it should last a long
I did my first tile floor in my bathroom about a year ago, it turned
out great. I found wood flooring under a layer of carpet and linoleum.
Instead of pulling this flooring I simply screwed it down to the
subfloor well and put concrete board over that, saved me some work.
I used the concrete screws found near the concrete board at your local
builders supply. They worked great for me and I didnt have any
problems with protruding heads even though they are a little pricey. I
didnt even consider nails, the floor was a little bit and need to be
tighted up with screws to silence it. A screw will set nicely into the
concrete board, then just fill it with thinset. I used a 14.4v
cordless drill and had no problems.
On Sun, 27 Mar 2005 23:00:26 -0500, Darryl
Actually the 1/4" Hardibacker tile backer product is superior to the
1/2" cement backerboard (and others) regarding not just strength and
density but in other important areas as well. At least that is what
the James Hardie Co. contends after testing, and after using a lot of
both over the years I concur.
As for the fasteners, 1-1/4" roofing nails are quicker, cheaper, and
more trouble free than screws, regarding getting them flush. I've used
both quite few times and gave up on the screws a while back. Mastic
applied to the back during installation of the backer is quick and
provides a great bond when installing it over plywood.
However, we do agree on using thinset for floor tile setting. Mastic is
not recommended for floor and some other tile applications.
Hi G Henslee:
I concurr with your assessment of the James Hardie product. I was
actually referring to 1/2" Hardibacker in my previous post. I, too
have used other products, like Durock, and found them more fragile and
more difficult to work with, though only marginally so.
When I recently rebuilt my tile shower because of a faulty shower pan,
I found sheets of 1/2" Durock behind the wall tile (thank goodness it
wasn't greenboard!). It had been nailed to the studs with roofing
nails, but many of them were loose, allowing the tile backer and tiles
to pull away from the wall a bit. This caused no cosmetic issues, but
still convinced me that roofing nails are inferior to screws when
fastening something that should last for decades. Of course, if you're
bonding the backer to the subfloor, it probably doesn't really matter
as the thinset or mastic will do most of the work.
Good point about loose nails. I also recommend screws for application
of backerboard or cement board for walls and counters, allthough mortar
is superior imho. I use the nails for floors only.
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