Designing Kitchens and Bathrooms - Hardiebacker questions

I see some tile guys, even pros, hate Hardiebacker because it is so thirsty and sucks thinset dry. I already bought it for a shower stall redo. How bad is it really?

I guess if I seal with Redguard or Laticrete, that would solve the thirsty problem.

Also, It appears many guys install backerboard after preslope and before mudbed. I guess Hardie must be installed AFTER mudbed since it would be prone to wicking if buried in the mud.

Comments please.

Well, no expert..but you asked for comments.

Can't see how wiping down with a damp sponge is any big deal. Makes sense to me. I wet the concrete block before I applied stucco, just so it won't dry to quick. They may even be saying it just to remove dust and stuff?

Don't see the point in the sealing before tile. More expensive and would take longer than wiping with a sponge.

But it appears you may be right about the spacing above the pan...though I don't see where they address mudbed specifically...they just say pan. Its a little hard to believe the Hardi would affect or be affected by being below the surface of a mudbed.

I only used Hardi on the floors, Durock for the walls, so the instructions/requirements were pretty different.

What gunguy said. There are always people that love one and hate the other. FOLLOW DIRECTIONS is what I always suggest. No one knows better than the manufacturer. Both are certainly much better that drywall, greenboard, etc.

I had a piece of hardibacker left over years ago, I stuck it under my 57 Chevy to catch oil drops. It has been there for years and still seems like new. Rain, snow, heat, matters not, just car covers, no garage.

Yes hardi seems to be a little thirstier than others. Just keep it damp with a sponge or spray bottle as you set the tile, no big deal. The Redgard is not necessary and an added cost.

For years I embedded wonderboard, durock and hardi in the final mudbed, and have never had any issues. We just talked about this on another thread.

Keep in mind that the pan liner will go 8" or so up the wall. Additionally, your vapor barrier should lap over the pan liner. Any minimal wicking should not harm anything, as cement and cement fiber boards are unaffected by moisture. A properly installed pan will send any water in the mud bed to the drain weepholes, so the bed should never be saturated to the point where wicking of the wallboard should be a problem.

Official TCNA position however is that the board should be slightly above the final mud bed with the bottom edge caulked. This will prevent any wicking, but also does not provide any support for the lower 6" of the board, as there can be no pentrations through the pan liner at least 3" above the finished height of the curb.

This has been discussed here and on other boards many times. It seems that some bury the board and some do not. Following TCNA handbook guidelines and the manufacturers recommendations is always your best bet.:)

So, Bill, until I get the common shaft seal on the vacuum pump/power steering pump on my Cummins, I can use a piece of Hardiebacker under it? Never thought of that, but it keeps customer's driveways clean. I'll try it.

Thanks guys,
Got concerned after talking with a couple of guys who really hate Hardie. Others, like you, said just make sure to wet it first.

As far as burying the board in the mud, I like the idea of support for lower portion of the backer and less chance to damage liner when doing the mud bed. Probably will install after bed per TCNA.