[Lizzrd02]

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 therefor 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!

 

[oh'mike]

Hardi is stiff as a board and will not behave like drywall----when the studs move with the seasons the board will not bend and move with them--causing the pops in the seams.

Also---what mud did you use while taping? Paper or Mesh?

There are three common muds used in a proper tape job--

Powdered easy sand---20-45-90 minute setting---hard--used to fill gaps--corner bead and sometimes used to embed the tape--hard to sand

Multi purpose---green lid---hard---contains glue --used for embedding tape--some pros use this for topping--hard to sand

Light weight---blue lid---soft---used as the final coat---easy to sand---should not be used to embed tape--or fill gaps or corner bead. It will crack.

 

[Lizzrd02]

We used sheetrock 90 and the recommended mesh tape. So do you think this will happen again and again simply because of the hardibacker walls and ceiling?
Do you think it would help to just redo the ceilings with green drywall? I don't think I can't convince my husband to do the walls too....

 

[oh'mike]

Part of the problem is the mesh tape---that is more prone to hair line cracks---

Certainly , overlaying that with drywall would help--but use paper tape in the field--use Strait -Flex tape where the wall meets the ceiling---

Use Multi Purpose (green lid) to embed the tape-----
If painted properly regular drywall is fine--no advantage to the green board---

 

[oh'mike]

 

[Lizzrd02]

Thank you! Now that brought up another question.....would that straitflex and tuff tape hold up to the corrosiveness of the hardibacker? You see we had a contractor do the taping and mudding for the bathrooms to help us on time, and I have my doubts that they used the correct mesh on all the seams.

We had two types of mesh tape on site at the time, and a few times I found the non-fiberglass mesh tape rolls in the bathrooms...not where they belonged!

But I was at work while they taped and it was covered in sheetrock 90 by the time I got there. I was not impressed with this particular crew of drywallers so I wouldn't put it past them to accidentally use the wrong one and say they used the fiberglass.

So....what I am thinking. If the tape you mentioned could be used on hardibacker, I might give it a try myself before bugging my husband about a new ceiling just yet. He is building a new business and I know the last thing he wants to hear is me nagging about drywall cracks in the bathroom. Lol
So what do you think? Is this a terrible idea? I figure all I am out is my time and a little bit of materials.
Thanks you for your help!

 

[oh'mike]

Regular drywall mesh will become brittle when exposed to cement products---if mesh must be used--be sure that it is tilers mesh intended for contact with cement products.

I prefer the paper tape----mesh tends to show cracks when the board moves ,while the paper bridges the seam and seldom cracks----

Strait Flex and paper ,set in multipurpose might fix up the existing work----might be worth experimenting--

But then again--that's a lot of expense and labor--so why not go the whole way and overlay some 1/2" drywall and start with a fresh surface?