Hello!So my husband and I completely remodeled our house a few years ago, including gutting the bathrooms. We somehow got the bright idea of using hardibacker throughout the whole bathroom....ceiling, walls, etc. We tiled the tub surround and then taped/sheetrock 90ed the seams. We then primed and painted the non-tiled walls and ceiling and it looked pretty good. The problem is, a lot of those seams are now cracking. (Where the ceiling meets the walls and on the flat surfaces of the ceiling at taped joints as well.)
I have two thoughts on this.
Around the same time we ended up adding a major supporting beam to the house that had been missing. Obviously, that moved some things structurally. We have had lots of new drywall cracks all over the house in the last few years, which I attribute to this movement and to a kind of hack drywall job by previous homeowners. The cracks are mainly in the ceiling/wall joints, some interior corners, and around the new support beam. So I guess I am wondering if these bathroom seam cracks are just a result of structural movement like the others.
My other thought is that the hardibacker is just not cut out to be a drywall product and therefore is causing the cracking due to its rigidity....? We did use all the appropriate tape and screws for installation.I am actually pretty good at taping and mudding seams, and my plan is to fix all of these cracks in the next few months so that we can finally be finished. I am REALLY worried that we screwed ourselves by using all hardibacker instead of normal green drywall like we should have. I hate seeing drywall cracks anywhere, it is just a huge pet peeve of mine. My husband is kind of burnt out and done dealing with it so I will be hard pressed to convince him to tear it out and use green drywall if need be. But I want to fix this so that I am not taping and mudding every few years. Please help!

This message has been edited. Last edited by: Lizzrd02,

You are probably right on both accounts.

Making the structural changes you mention can certainly cause hairline cracks all over the house. Also, even though it appears to be rigid, drywall is soft enough so that there will be a small amount of 'give' to it. This will allow enough tiny amounts of movement to help keep down the tape cracks. Hardi, on the other hand, is completely rigid and will transfer all stress to the weak point - all your seams.

If you hate wall cracks and never want to fool with them again, then I think your only option will be to remove the Hardi that is not used as tile backer and replace with drywall. The only 'improvement' you could make to the Hardi would be if you originally used paper tape on the seams. If so, then you may get long-term results by either removing the paper tape and retaping with fiberglass mesh tape, or double taping fiberglass mesh over the paper tape seams. However, if you did use the mesh tape the first time then this will not work.

I really think your best fix will be to cut out the Hardi within a few inches of the tile and replace everything with drywall.

You could try a product like this before you go and tear out the hardi-backer.

http://www.homedepot.com/buy/f...-u.html#.UQ-09aU0V8E

Thanks for all the input! I should mention that I have my doubts that the correct fiberglass mesh was used on all the bathroom seams. We had a contractor tape and mud the bathroms to help us on time, and a few times I came back from work and found the non-fiberglass mesh rolls in the bathrooms. The drywall crew was not the greatest so I could see them accidentally using the wrong kind and then saying they used the fiberglass.
Someone in another forum mentioned straightflex tape and tuff tape....but I wasn't clear if that would hold up to the corrosiveness of hardibacker. But since mesh tends to allow cracking more than tape, I am wondering if I could use this tuff tape instead? I am thinking of just redoing the seams myself to see how it goes.