Drywall - does it need time to dry afer manufacturing
Drywall - does it need time to dry afer manufacturing
(OP)
Does drywall need time to dry after manufacturing, to reduce shrinkage? I realize that drywall expands and contracts subtantially with changes in the relative humidity in the room, but is there also a shrinkage component due to drying out after manufacturing, or has that all occurred by the time of shipping of the drywall?






RE: Drywall - does it need time to dry afer manufacturing
http://m.youtube.com/watch?v=tmbk8Pfau0I
RE: Drywall - does it need time to dry afer manufacturing
As is common with construction, the buildings are relatively open for a long period of time, even after the drywall goes up. As with most construction sequencing, there is no time allotted for acclimation once the drywall is installed but before the joint taping takes place. This usually occurs at the same time or in very close proximity to the placement of the drywall. The problem all of this creates is that once the building is closed up and the HVAC system is commissioned and running, the interior humidity drops quite a bit and removes moisture from the drywall, which in turn, causes shrinkage of the drywall. Since all the joints were done at a higher relative humidity, you commonly see cracks develop at re-entrant corners and room corners from the shrinkage. This is almost always alarming to occupants, but is cosmetic only.
RE: Drywall - does it need time to dry afer manufacturing
Do you think that if the wider cracks at th re-entrant corners are repaired (and the hairline cracks at other re-entrant corners are left as is), and the repair is done on a cold winter day when the inside relative humidity is very low (around say 25%), that the repaired cracks will stay good? I have a feeling that they will re-open in the next winter, although perhaps only to hairline width. What do you think?
RE: Drywall - does it need time to dry afer manufacturing
RE: Drywall - does it need time to dry afer manufacturing
RE: Drywall - does it need time to dry afer manufacturing
The usual stucco control joints are either a 3/4" deep "V", or a 1" x 1/4" "C" using galvanized sheet metal.
Usually when I see stucco cracks they occur just about anywhere, not just wall to ceiling and at corners of windows and doors.
RE: Drywall - does it need time to dry afer manufacturing
http://www.gyprock.com.au/Documents/GYPROCK-570-Ce...
RE: Drywall - does it need time to dry afer manufacturing
hokie66 (Structural) - thanks for the info about spacing of drywall control joints, and the link. How do you come to know about Australian control joint recommended spacing...are you based there? Is it a Code there that makes this recommendation, or is it just standard practice there?
I will try to send you a photo of the condition that I am referring to...either later this evening or Monday morning...
RE: Drywall - does it need time to dry afer manufacturing
RE: Drywall - does it need time to dry afer manufacturing
RE: Drywall - does it need time to dry afer manufacturing
wannabeSE (Civil/Environmental) - those references are really good stuff. Thanks so much.
I don't have a really good photo of the condition where there is a crack, but the attached does show it. I think it is caused by the retraint to horizontal movement caused by the concrete beams that extend thru the vertical face of the bulkhead.
I wonder if a fix would be to rake out a 6 mm wide gap betwen the edge of the drywall and the vertical face of the beam and fill it with white silicone. I suppose that would not work if there is a metal stud that is fastened to the beam side and the drywall is fastened to the metal stud.
RE: Drywall - does it need time to dry afer manufacturing
Would moisture resistant drywall react less to humidity changes?
RE: Drywall - does it need time to dry afer manufacturing
Cementitious backer board has less sensitivity but cannot be finished to the same level as drywall. It will appear rough. If you wanted to put a sparge coat of plaster over it, that would probably solve the appearance issue.
The Gypsum Association information that wannabeSE referenced is downloadable. The ASTM standard is about $40 US.
RE: Drywall - does it need time to dry afer manufacturing