# Drywall panel orientation question



## tpagel (Jan 30, 2008)

I am going to be drywalling a cathedral ceiling in my attic. The plane of the rafter-spanned space is about 17' wide x 44' long. Does it make any difference how I orient the panels to create the ceiling. Was going to orient them parallel to the long dimension of the roof ("sideways"), and stagger them like a brick joint. The problem I see up here is that I believe the roof will sag and move more than walls, so cracks are more likely. Is there a way to minimize cracking with panel orientation? Are there more "flexible" drywall compounds to use, which would resist cracking? I typically use pre-mixed all-purpose lightweight compound.

Thanks in advance


----------



## tpolk (Nov 7, 2009)

rafter size? roof pitch? kneewall? collar ties? length of rafter being covered? age of house? roofing material?


----------



## Bob Mariani (Dec 1, 2008)

install your panels perpendicular to the rafters. If the ceiling is built correctly there is no reason to get cracks. Use 5/8" drywall. Use Durabond 90 for the first two coats. Use the pre-mixed only for the last coat.


----------



## tpagel (Jan 30, 2008)

Rafters are 2x8 at ROUGHLY 12" OC (some centers are 9-10", some are 13-14"). The depth as been extended to get decent insulation in the ceiling cavity. The guy who framed the house was not skilled. The rafters are not all in-plane, the collar ties are not all level or at the same height, and basically, the fastening methods and joinery are not all that attractive. The roof has a sagging ridgeline already, so I really think there will be movement again at some point. The house if 50 years old, so it has pretty much settled and developed its own load idiosyncrasies, I think.

Can I use Durabond 90 on existing drywall cracks as well, as a lasting remedy?


----------



## tpolk (Nov 7, 2009)

if you sistered to the sides of rafters for extra depth this will help to stiffen the span. hopefuly you ran stringline so bottoms are in same plane. same with ceiling collar ties.bob is right perpendicular is better altho 1/2" would probably work on those centers. ridge has probably gone where it will but if you have room you can add a stiffener to attic side of collar ties and brace to ridge in several spots


----------



## tpagel (Jan 30, 2008)

Thanks for the replies, guys. I appreciate the advice


----------



## jogr (Jul 24, 2007)

If you are finishing an unfinished attic space that already has sagging then you are adding weight to an already sagging structure and will very likely increase the sagging unless you've fixed the structural issues. 

17' wide attic, collar ties and finished space doesn't add up to me. Do you have a really steep roof? Even so it seems like you'd only have a very narrow strip with enough headroom to stand up. 

2x8 rafters at 12" oc should not sag if the ridge to plate distance is 8 1/2 feet. Are the walls the rafters sit on pushing out?


----------

