Hello all, I am working on a new school in the intermountain west. We have had a reoccuring poroblem with the butt joints cracking in the gym. Fixes tried so far have been to dig out the crack, use fiber tape and hot mud. The cracks returned. Up to this week the cracks have been confined to the gym which is rocked with abuse board. My assumtion was that we had a compatability problem with materials. This week the low exterior classroom walls are starting to crack. Thease walls are general type "x". A fix I'm going to have the sub try on the remaining exterior walls is to hand the rock vertically, eliminating the butt jonts. I am hopefull this application will work. However, this does not help me with the repairs to the reoccuring cracks. Does anyone have any experience of new ideas I might apply here? Thanks.

Butt joints should not be on webs. Use an adhesive foam behind the edge of each piece of sheetrock at the butt joint. Then treat it like any sheetrock butt joint. I work with ARXX forms and it is not practical to have the joints meet at a web. I hope this is a good solution.

BruceM

butt joints,
how tall are the ceilings?
we run 10 or 12 feet floor to ceiling no but joints at all.
stand up the rock.

The gym walls are 34' tall. I have changed the application proceedure moving forward. My issue is what can I do to fix the butt joints in the materials already in place?

Thanks.

You might try a product called Rapid Set One Pass drywall repair material and joint compound. (www.rapidset.com) It is a cement based product that sets up and drys very fast. (Patch, sand and paint in under 2 hours). It doesn't shrink, is water resistant when dry, and a lot stronger than conventional joint compound. No guarantees, but we have used it to fix a lot of small problems.

I had the same problem on a 24' tall gym wall w/ the hardend Gyp. I believe that part of the problem might have been that we rush to install drywall over walls that have not had time to set properly, thus the cracking.