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Rafeek
02-23-2004, 05:19 PM
I have seen cracks between various drywall ceiling planes in cathedral, coffered or just fancy raised ceilings along the taped joints.

What is the procedure or what type of tape or special beads should be used?

I just saw this in new construction that has been completed since 6 months in the Chicago area.
The house may have been kept at a lower temperature over that period. How much of a factor is that.

Wmp
02-23-2004, 05:47 PM
wood expands and contracts, and new lumber isnt all that dry so it shrinks. Typically this happens after the first cooling and heating cycle.

Myron has written articles on how to deal with this by the way the rock is screwed/nailed/glued near the stress factors.

Cracks in these types of ceilings arent uncommon, but can be avoided or reduced by the way you hang rock and the type of mud you use.

Lightweights and all purpose muds IMO are more prone to this due to the lack of glues or binders in the mud. Using plain paper tapes cant handle this stress, there are special off angle tapes from trim-tex, no-coat, and others have addressed this issue with special tapes that should be set in a setting compound or taping compound. Strait-flex i believe makes a special glue you add to regular mud to give it more binder (glue)

RickA
02-25-2004, 03:33 AM
I concur with Wmp, the only material to use is a flex bead. That way the stress point can grow or shrink and the flex material will absorb it.

--rick

Myron Ferguson
04-05-2004, 08:17 PM
Trim-Tex does make an excellent product for this exact issue. It is called Magic Corner. It can be put on straight by snapping a line on the drywall. Glueing it and stapleing are also necessary for best results.