HardieBacker 500 Cement Board is made of cellulose fibers, crystalline silica, and portland cement. It can't be used in a steam shower and crystalline silica dust is a carcinogen.

The other cement based backerboards are usually fiberglass mesh reinforced concrete (portland cement and expanded clay aggregate) and are impervious to moisture and heat.

The choice depends on how much moisture and/or heat the tile will be exposed to.

"...crystalline silica dust is a carcinogen."

Silicosis (caused by inhaling respirable silica) is not the same as cancer.

You can worry about Silicosis and I'll worry about cancer.

Silicosis requires "repeated and prolonged overexposures" to dust containing crystalline silica so it is an unlikely problem for a homeowner. However, the degree of exposure needed to cause cancer is apparently not known so I would consider it more of a risk to a homeowner.

The MSDS sheet for HardiBacker says:

Carcinogenicity:

California Proposition 65 Warning: Respirable crystalline silica and carbon black are known to the State of California to cause cancer.

International Agency for the Research on Cancer (IARC):
Crystalline silica inhaled in the forms of quartz or cristobalite from occupational sources is carcinogenic to humans.

The National Toxicology Program (NTP): NTP has concluded that respirable crystalline silica is a known human carcinogen.

...such as moving the bulk of the company offshore (from Australia, it's an Australian company) to protect its assets from asbestos related claims.

If Hardie doesn't take steps to protect its assets and goes belly up in a bankruptcy proceeding, won't the same folks be complaining that Hardie didn't do enough to protect the jobs of its workers?

"Carcinogenicity:

California Proposition 65 Warning: Respirable crystalline silica and carbon black are known to the State of California to cause cancer.

International Agency for the Research on Cancer (IARC):
Crystalline silica inhaled in the forms of quartz or cristobalite from occupational sources is carcinogenic to humans.

The National Toxicology Program (NTP): NTP has concluded that respirable crystalline silica is a known human carcinogen."

Like anything else, the does makes the poison and cancer is no different.

in your bathroom you may want to know a few facts practical to your bathroom.

1. These boards do not replace the need for a membrane.

2. Lining up a wall with tiles on one part of it and painted drywall on another part of it:
I.E. With thinset and tile, how thick will it be?
- Cement boards are 1/2 inch thick and Hardi 500 is less than 1/2 inch thick.
- Hardi 1/4 inch is also available and it is a good substrate for tiling walls.

3. With inexperienced tilesetters, how hard will it be?
- Hardi needs more moisture and if it's your first time you may botch it a bit and ultimately be frustrated or not as good. OTOH if it's your first time you might mix the thinset too wet and loose and Hardi compensates Ha-ha against this greenhorn mistake.

HTH
-david

1/4" Hardibacker is intended by the manufacturer for use as an underlayment on floors and counters but not as a substrate for wall tile.

The 1/4" Hardi was the only one, originally --- and for many years it was used on walls (and specc'd for walls). One cut strips of it to fur out to 1/2 inch when needed. Just F.Y.I. and AFAIK it is still an option for walls, it was never outlawed and there was never a prohibition against it and the firm never issued an advisory remark not to use it.... Besides, why not sell more when they can get away with it? On top of that, I think people in general like to overdo things a lot when they're not cutting corners and going cheap... and so, hey, for sure, why not buy 1/2" when it's right there in front of you in the store and it feels solider and in any case what makes you think 1/4" will be enough...

It's really strong to start with, and even moreso when tiled. Your call.

-dr

Chipster,

Both boards essentially serve the same purpose.

Personally I prefer true cement boards...Durock and Wonderboard. On your walls use 1/2", not 1/4". Quarter-inch is not as rigid as 1/2" and you can get flex problems.

Where I do like Hardie (which is a fiber-cement) is when I need 3" or 4" wide strips as in lining a niche. Thin strips of cement board are more brittle than hardie.

Overall, again, two good products. But my personal preference is for cement board over fiber-cement.

Mongo

"If Hardie doesn't take steps to protect its assets and goes belly up in a bankruptcy proceeding, won't the same folks be complaining that Hardie didn't do enough to protect the jobs of its workers?"

Umm no, because those same folks will be dead. They also dragged proceedings out as long as possible, because quite a few of the complainants were in the final stages and it became quite likely they wouldn't see a cent.

If you had read some of the reports about Hardie's conduct you wouldn't be so quick to defend their conduct. They knew exactly what they were doing. Like I say there's a lot of legal stuff going on so I'm not the only one who feels they did not do the right thing.

Umm no, because those same folks will be dead. They also dragged proceedings out as long as possible, because quite a few of the complainants were in the final stages and it became quite likely they wouldn't see a cent.

So if they're still dead, isn't protecting the current employees just as important? It's not like a big check in the pocket of the deceased relatively will bring the deceased back. How about the current crop of shareholders? Do they have the right to expect management to protect their investment?

I don't know of many private citizens, when faced with a lawsuit, that simply toss up their hands and say, "Please take everything I have..." Why is it when a company tries to protect its assets, the company is doing something wrong?

It's not like the company was innocent in all doings, people since Pliny have known of the danger of asbestos, and failed to take adequate precautions to ensure the safety of its workers, not to mention the end users - mesothelioma etc is starting to crop up in people whose only exposure to asbestos has been working in schools or being unlucky enough to be playing in the backyard whilst dad was demolishing or building a shed.

Mike, I hope you are overlooking the fact the company did wrong, knowingly, and compounded it by cynically hiding its assets and leaving a woefully underfunded shell company holding the bag.

Following your logic, it would be ok for companies to assassinate whistleblowers to protect its assets, the company that made exploding Pintos did no wrong, and coverups are a good thing because it protects the shareholder's interests?

I'm sorry, I'm horrified by your callousness. No, the money won't bring those people back, but these are families who have lost loved ones and providers, and often have gone deeply into debt, caring for the sick (and they are ugly diseases with much suffering) and trying to provide for themselves.

As a person who considered myself Australian, I tried to support Australian businesses, but I cannot support anyone whose conduct is morally reprehensible.

It's not like there would be a free-for-all where the company would be stripped bare - and if the amount of compensation required amounted to that, so be it - estimates were prepared years ago for what the compensation would amount to, they left the shelf company with funds well short of it, knowingly. The conduct has been judged as criminal in some cases, as the attached link attests.

It's not like the poor shareholders are caught flat-footed, either. The company has been extremely profitable world-wide, and the shares have been traded freely. People again have knowingly invested in, or continued to hold shares in the company with this over its head.

I guess you don't believe in accountability in government either? I am staggered by your callousness.

Here is a link that might be useful: Recent James Hardie history

"...crystalline silica dust is a carcinogen."

Silicosis (caused by inhaling respirable silica) is not the same as cancer.

Actually, he's right-- it is a known carcinogen, and has only recently (within the last 5-6 years) been recognized as such. The only time it's dangerous, though, is during installation, while being cut. once installed, it's pretty harmless.

Brickeye-- I'm surprised you haven't heard about this, as it pertains to masons as well as tile guys.

As for the original question, it's either or, so long, as someone mentioned, you're not doing a steam shower. other than that, either Fiber board or cement board is acceptable, and one is just as good as the other. It's pretty much up to the disgression of the installer, and believe me-- every one of us has our own favorites.