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Blogger Pittsburgh, PA on Sep 08, 2012

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HardieBacker: Your Tile Floor Isn't Moving Once It's Installed

My sister wanted her new porcelain tile floor to look great. One way we accomplished this was by using HardieBacker underneath it.

My last few posts share why I love this cement board and how it prevents cracked tile. Today I want to show why the Incredible Hulk would have a hard time moving your tile once it's properly secured on top of HardieBacker.

Here are some quick takeaways that will help you understand why:

+HardieBacker should be placed on a supporting bed of thinset

+Use alkali resistant screws to fasten the HardieBacker to the wood subfloor

+Screws should be fastened every 8 inches within the panel field

+Fill joints between HardieBacker panels with the mortar you'll use to install the tiles

+Embed alkali resistant fiberglass tape on top of joints

+Smooth out the mortar that oozes out from the tape to avoid uneven tiles ...»

15 Comments

Mark Potter Lagrangeville, NY

good post! although I must add that having a sturdy and sound subfloor and joists is what you need to consider for deflection ( up and down movement) cbu will not deflect movement subfloor ply wood will. Hardibacker is my choice for thinset bond over tile.

on Sep 09, 2012 · Like 1
Home Repair Tutor Pittsburgh, PA

Thanks Mark for the great comment. I completely agree with you in regard to having good wood subfloors and sound joists. My last few posts touched on these topics but I should have mentioned them again :)
Looks like we both love HardieBacker for floor tiles. Do you have a preference for cement board types in vertical wall applications? I have to admit I like DuRock for shower and tub surrounds.

on Sep 09, 2012 · Like 0
KMS Woodworks Nederland, CO

Your pic looks like 1/4" thick backer...the 1/2" stuff is even more bomb proof, but may pose problems if you are mating to some regular thickness hardwood flooring. I have found the 1/2" to add some of that extra stiffness that would come from adding ply.

on Sep 09, 2012 · Like 1
Mark Potter Lagrangeville, NY

@kms, let's not confuse people you can put down 3 sheets of cbu and will still have up and down movment. tile remmendations are to use 1/4" for floors people do use 1/2" but when you do use 1/2" your giving your self to much space between ply and cbu cuz you have to up the trowel size making your thinset lines bigger and only voiding the prevented movement so in other words to much cement aka cbu and thinset makes the plywood to not do its job well. ...»

So a subfloor of 3/4" and 1/2" on top should be used for maximum strength. If the hight is a issue ditra will work as a filler bond.
I do not like durock at all although 1/2" or 5/8 is what is use for walls pending your drywall match up.

on Sep 09, 2012 · Like 0
KMS Woodworks Nederland, CO

I normally use the 1/4" hardi-for floors but on some occasions have used the 1/2" When I was putting in the flooring at our off grid cabin I used 1/2" wonder board. Being more "cement" like the wonder board added some nice thermal mass. With the tile and the board I calculated about 1800 pounds of mass. Our cabin is passive solar, and stick built, Ideally It would have been nice to have a poured slab but cost and terrain had me build with 10" TJI's and 3/4" ply...that floor is bomb. ...»

Here is a pic in the "winter season" with the sunshine warming the entire width of the floor...the wiener dog loves it.
on Sep 10, 2012 · Like 0
Sharron W Memphis, TN

I'm a huge fan of the hardi-board products....when one of my coworkers was talking about adding a "clubhouse" (rest-stop, no matter what they call it...LOL); at the shooting range I asked about accidental "shots", and so we went out and Shot a few pieces of Hardiboard siding and backers....I have to say I was stunned at the ability to withstand or deflect some of the ammo those guys used...LOL Not that you'd want to deliberatly shoot your floor or house, but it makes me feel better about ...»
my mom's house in the country during turkey time... The outside siding came out so well it barely took off the paint...in one tiny spot the size of a pencil eraser.... and that was a 12Ga at 100 ft.

on Sep 10, 2012 · Like 0
Beth B Birmingham, AL

Wow, that's good info to know, Sharron. We use Hardi all the time at my office (in the construction field) so I might need to quote you on that! :)

on Sep 10, 2012 · Like 1
Sharron W Memphis, TN

@ Beth, take it out and shoot a piece....and keep it on hand marked up with the stats....as far as I'm concerned, that's one of the best selling points I can think of, LOL I wasn't in their "gun club" but I managed the companies Safety, Quality and Environmental Programs...and so many of the employees WERE in the gun club it freaked me out when they started talking about where it was going to be situated....so we went out and did a "safety" and "quality" test...LOL

on Sep 10, 2012 · Like 0
Sharron W Memphis, TN

@Beth, That might be an additional selling point for your construction team...and won't you look good for thinking of it...

on Sep 10, 2012 · Like 0
KMS Woodworks Nederland, CO

Bird Shot from a shotgun at 100 feet...is pretty wimpy compared to a rifle bullet. These attached pics are some of my 3/8" thick solid steel target plates...most the the dents and dings are from pistol loads at 30 to 50 feet...these are .22 to .45 cal.
The big dent was from my M4 Carbine in 5.56mm with a regular 55 grain round at 100 YARDS...The Hole completely through the steel is from a NATO 855 penetrator round from my same M4 Carbine ...»
also at 100 YARDS.
Some hardi may be OK for bird shot...but if Rifle rounds are involved...you better not be downrange...LOL
on Sep 10, 2012 · Like 0
Sharron W Memphis, TN

@KMS, This was a 12 ga slug and It wasn't backer board, it was a siding and it wasn't a flat siding it was slightly convex and painted with a polymer paint. It didn't even dent it except slightly in one tiny spot smaller than a BB, and took off the paint about the size of a pencil eraser. maybe because it was convex the pellet glanced off but I have to say I was pretty stunned by the lack of damage. but it's not the same siding we used on Mom's house....her's was completely flat and we had ...»
to prime and paint ...I'm not suggesting people go shooting there houses...just that it impressed me when they shot it ...

on Sep 10, 2012 · Like 0
Sharron W Memphis, TN

@KMS, I forgot to say, HOLY SMOKES! glad those guns aren't everywhere...

on Sep 10, 2012 · Like 0
KMS Woodworks Nederland, CO

I guessed bird shot based on your comment about Turkeys....I don't know of any one who hunt fowl with slugs.

on Sep 11, 2012 · Like 0
Home Repair Tutor Pittsburgh, PA

Well I guess Hardie makes good products overall. I'm glad you shared your experiences Sharon with the Hardie siding. We are thinking of using it

on Sep 11, 2012 · Like 1
Sharron W Memphis, TN

@KMS, sorry I was confusing....the gunclub building was one event....mom's neighbors turkey hunting is entirely seperate....

on Sep 11, 2012 · Like 0