Replies

1. 
   LEMONJELLO | Aug 26, 2005 08:27am | #1

   Drywall gun, screws, either hardi screws or deck screws, follow the black dots on the hardi board and you are golden. Wonderboard was great in its day but hardi is eisier to work with in my opinion and scewing the dog out of wonderboard will crack and leave crumbly edges and corners. bad habit of snapping when trying to lay a sheet on the floor. Then! you'll have to vacuum or sweep all the little cement rock granules b'cause they will annoy the piss out of you when you spread thinset and also end up under the tile you just layed and cause a lump,...then you gotta lift the tie again, find the annoying little cement rock and reset the tile with thinset now all over, P in the A.....

   any tilesetter will tell you the same and I doubt you will hear a different opinion than mine, unless they work for the wonderboard Co....

   I cut the board twice and its still too short ! ! !
1. 
   WillieWonka | Aug 26, 2005 08:58am | #2

   That was funny, and an analogy from experience no less. I had that same problem, so I KNOW what those granules will do to you. Hardiboard is by far better nowadays. If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time.  -ME

1. 
   LEMONJELLO | Aug 26, 2005 09:11am | #3

   My Pops been a tile setter for ever!! There is not a stupid tile mistake I haven't made and will never hear the end of. I am probably one of the few my age who can float a shower (although a rare occasion), or a floor for that matter...For you old timers, I can get most of the mud on the wall without half of it on the floor
   I cut the board twice and its still too short ! ! !

1. 
   WillieWonka | Aug 26, 2005 09:25am | #4

   Ah yes, nothing like being the son of a tradesman. I never had that, I taught myself all I know. So when it comes time to making fun of my mistakes and never letting me live it up, I get to play both roles of yeller, and receiver of the yeller :)If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time.  -ME

2. 
   brie | Aug 26, 2005 04:23pm | #6

   thank you all for your input...hardie backer it is!

1. 
   custombuilt | Aug 26, 2005 06:20pm | #7

   the only bummer about the hardibacker is cutting it can be pretty dusty.......but then again with the wonderboard, you get that crumbly mess.   To me it really doesn't matter.....i've done both and haven't really developed a preference.  You do have to vaccum up all the crumbs with wonderboard, but I vaccum up regardless before thinset. 

   It seems like around here, whenever we've done custum sub jobs, then always have wonderboard down......probly cause its slightly cheaper.

1. 
   brie | Aug 27, 2005 06:03pm | #8

   thank you all for your input. more questions...is hardieboard a stronger material (when installed) than wonderboard? i have plenty of room (height-wise) and think 1/2 hardieboard might have less flex than wonderboard. i used 1/4" hardie on stair risers years ago and remember that getting screws through it being very difficult. but that may be because it was a vertical surface, and lately, i use wonderboard, but for this application (bathroom floor) i want to make the floor as rigid as possible.

2. 
   DonCanDo | Aug 26, 2005 01:38pm | #5

   Hardiebacker (I think that's what they actually call it) also comes in 1/4" boards.  That can be very helpful when you're trying to avoid adding too much height.

   -Don

3. 
   MikeCallahan | Aug 27, 2005 08:09pm | #9

   I like hardibacker too. I use a portable table saw with a cheap diamond blade to rip it. I blow the saw after with compressed air. I use the saw outside with a vac for dust collection. For screwing down, I like to use a carbide tipped countersink. It is made by Amana. The drill bit dulls quickly and I have to change it frequently but the countersink lasts a long time. They cost about 25 bucks though.

   Mike Callahan, Lake Tahoe, Ca.
4. 
   WayneL5 | Aug 27, 2005 09:08pm | #10

   Hardie Backer is stronger.  In fact, when fastened according to specifications it can form a rated assembly for sheer wall construction to resist earthquakes.

   The screws made for the board should be self drilling.  They have a thin profile head (thinner than drywall screws) and serrations on the underside of the head which grind a countersink as you install them.  They don't need to be completely flush, if they stick up 1/32 of an inch they are still comfortably below the thickness of the thinset.

   Hardie Backer does dust, which can interfere with spreading the thinset.  I vacuum thoroughly, then wash the surface with a cloth rag and clean water to remove the dust.  Just before I spread the thinset (while it is slaking) I dampen the surface again with a wet rag.  Apply the thinset with the unnotched edge of the trowel first, pressing and spreading to obtain good adhesion.  Then add more if needed and comb to proper height with the notched edge of the trowel.

5. 
   JTC1 | Aug 27, 2005 09:56pm | #11

   I am a remodeler in non-earthquake country, afraid I cannot comment on the structural strength of Hardi vs Wonderboard, however I don't think either adds a tremendous amount, I believe it's the plywood and joisting underneath that provides 99% of the structural strength and stiffness.

   A few comments on Hardi installations:

   Screws: I like Phillips II Cement Board Screws - Lowes carries here in Delaware. Available in 1-1/4" or 1-5/8", anti-corrosion coated in attractive lime green, #2 Phillips drive, extra large wafer head.  Screw shank has a knurled section just below the head and flutes on the underside of the head - given enough down pressure and torque from your drill you do not need to pilot or countersink - fast driving speed works better than slow.  I do not own a cordless drill with enough guts to set these screws.  I use a 20+ year old 3/8" Makita corded drill with mag insert and driver bit, does just fine.  These screws do not work well with my Milwaukee screw gun - large screw head interferes with the nosepiece; could remove nosepiece I guess - would work like my Makita only be red.

   Cutting:  I cut outside but do not generally use a saw.  I score and snap with a carbide scribing tool and straight edge.  Tool produces a V shaped groove, tool looks like a single v-shaped carbide saw tooth on a bar with handle.  Score several times from the back and snap upward.  Produces a decent cut.  If you want or need to smooth the cut edge, 60 grit sandpaper with a block makes short work.  For cut outs / notches where snapping is not practical I use a saber saw with a Remington abrasive blade - dusty but cuts fast and easy.  Blade has no teeth - looks like a regular steel saber saw blade with grit glued to the leading edge where the teeth would be.  The material is very tough on steel cutting instruments, saw blades, hole saws, drill bits, etc. and I try to avoid their use if possible.

   Installation: 30# felt stapled to plywood floor as moisture barrier, thinset, 1/4" or 1/2" Hardi screwed every 8" (your 6" is fine), fiberglass tape and thinset the seams in the Hardi; then thinset...heating..stone as described in your post.  Purpose of thinset under the Hardi is to fill any minor dips in the wood floor and provide 100% support to the Hardi and subsequently the stone.

   Enjoy!

   Jim

   Never underestimate the value of a sharp pencil or good light. 

1. 
   brie | Aug 28, 2005 07:39pm | #12

   thank you all. your combined experience, expertise, and suggestions have really helped me in my decision making process. much appreciation.