GAF and Giles117

rsandberg · Post by **rsandberg** » Sat Jan 22, 2005 3:48 am

Hey Bryan,

Fellow Detroiter here (well actually Livonia but don't hold it against me).

I found the GAF Tri-Ply at HD and wondered...

If used inside a Drywall - GAF - Drywall wall layer do you recommend gluing the GAF on both sides to make a constrained layer, or just use screws?

Thanks,
Rick

knightfly · Post by **knightfly** » Sat Jan 22, 2005 5:09 am

Not Giles, but I'd do the sandwich thing (glue both sides) - there are companies who sell similar products for LARGE amounts of money, and it's not that they won't work; it's just too much money for common sense.

If you want simple, just use another layer of gypsum - a layer of half between two layers of 5/8 is another good way.

Or, if you want the benefits of dissimilar leaves, do one leaf as 5/8-1/2-5/8 gypsum, and the other as two 5/8 gypsum with the GAF laminated between.

Unless you can figure a way to do this in situ, you'll need to caulk between "sandwiches" very carefully, or you'll lose isolation at the joints - if you build the sandwich in place, you can overlap seams to negate this problem... Steve

rsandberg · Post by **rsandberg** » Sat Jan 22, 2005 5:56 am

Thanks for that.

I'll probably go the 5/8 - GAF - 5/8 route. Do you think the glue like used to hold rubber baseboards against drywall would work?

Of course, like everybody else I'm looking for the most cost effective solution.

Thanks,
Rick

knightfly · Post by **knightfly** » Sat Jan 22, 2005 6:07 am

If you plan to build individual sandwich panels, I'd use contact cement - tricky part is getting the contact cement to work without grabbing the panel when it's out of line with the triply sheet - one way would be to use 3-4 sawhorses to support a sheet of drywall, then lay the rubber over that (no glue yet) then,butter the upside of the rubber and the downside of another drywall sheet, clamp some 2x4 scraps to the two outside sawhorses for an edge guide, shove the bottom wallboard and rubber up against these stops, then (after the contact cement is tacky/dull) slide the upper sheet down these stops (used as a guide) until that edge touches the rubber, at which point you are committed; now, allow the rest of the sheet to come in contact with the glue line, use a hard rubber roller to make sure they are firmly stuck, then flip the whole thing over and repeat the process for gluing the OTHER wallboard layer onto the rubber. Now you have a sandwich - probably will need to trim the rubber with a razor knife to match the edges of the rock.

Be sure to put both beveled edges of the wallboard AWAY from the rubber; otherwise, you'd have a slight air void between rubber and wallboard where the bevels are (Wallboard is beveled on the long edge, to make room for mud/tape)

Not sure how you'd do it if you laminate while it's on the stud frame, never used contact cement for anything that large that wasn't horizontal so I'm not sure whether it would "creep" or not... Steve

rsandberg · Post by **rsandberg** » Sat Jan 22, 2005 8:03 am

Man Steve,

Did you do that all in your head or have you done this like a 100 times? You must have a heck of a time sleeping with an active mind like that.

I greatly appreciate the advise and will let you know how it goes. I'll probably take some pics too.

Sincerely,
Rick

knightfly · Post by **knightfly** » Sat Jan 22, 2005 9:21 am

Yeah, it just comes of the top of my head (scum floats

) - sleep comes best when I'm too exhausted to think, that way it shuts me down for a few hours almost automatically...

Pix are always good; be sure to downsize them to 750 pixels wide, or the bbs software makes you scroll sideways to read stuff... Steve