Gypsum Sheathing

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Author Message gerard sanchis New member Username: Gerard_sanchis Post Number: 7 Registered: 07-2002 Posted on Monday, August 26, 2002 - 06:59 pm:    Where do you all specify gypsum sheathing? Most of our work includes gypsum sheathing as a substrate for exterior waterproofing in a cavity wall or as a substrate for cement plaster. Up to this point, we've included it in Division 9, but it certainly is not a "finish." It probably belongs in the 07400 series. I'd like your thoughts on the subject? Anne Whitacre New member Username: Awhitacre Post Number: 11 Registered: 07-2002 Posted on Monday, August 26, 2002 - 07:22 pm:    We put it with 05400 if we have that section in the specs; this is analogous to putting it in with rough carpentry (06100) on a wood framed building. Typically, our gyp sheathing is used behind several finishes -- brick veneer, metal panels are typical -- and so we have it installed with the light gage framing. We also up here in Seattle typically just use the Dens-Glass exterior boards, and not typical gyp sheathing -- the cementitious boards hold up under our climate better even when exposed. David Axt, AIA, CCS, CSI Junior Member Username: David_axt Post Number: 46 Registered: 03-2002 Posted on Monday, August 26, 2002 - 08:46 pm:    At our office we have a separate Section 09253 - Gypsum Wall and Soffit Sheathing. I agree with Anne. Dens-Glass is the way to go in Seattle's wet climate. Other gypsum products will either deteriorate or become "mold munchies". John Regener, AIA, CCS Unregistered guest Posted on Tuesday, August 27, 2002 - 12:43 am:    I use Section 09253 - Gypsum Sheathing. It's not particularly logical but it does conform to MasterFormat. I'm not clever enough to figure out which trade is supposed to install gypsum sheathing so I don't specify it with the framing. I also don't specify interior lightgage metal framing and gypsum board together nor do I specify installation of door hardware in the finish carpentry section. Doug Frank CCS New member Username: Doug_frank_ccs Post Number: 4 Registered: 06-2002 Posted on Tuesday, August 27, 2002 - 09:12 am:    I typically spec sheathing in "Gyp Bd Asemblies" since I prefer to avoid narrowscope sections if I can (I find that I end up repeating most Part One stuff over and over in using narrowscope sections). Like most of you, I too spec Dens Glass exclusively (until the other guys can match the mold-resistance testing). That's a pretty important issue in Houston. John Bunzick, CCS, CCCA New member Username: Bunzick Post Number: 26 Registered: 03-2002 Posted on Tuesday, August 27, 2002 - 09:48 am:    John, I've never been able to figure it out either. I spec gyp sheathing differently depending on the project and the building's skin. Here in New England, Dens-Glas pretty much is the thing to use also, but we're not so worried about mold, just general deterioration. Massachusetts now has a very stringent requirement in the energy code for air barriers, which has resulted in extensive use of self-stick building wraps like Perm-A-Barrier. This may end up changing the type of sheathing used, since it is more protected, but it hasn't been in effect long enough to gauge that result. Richard L. Hird Unregistered guest Posted on Wednesday, August 28, 2002 - 10:08 am:    I use "06167 Gypsum Sheathing" because we often use wood sheathing with and gypsum sheathing for shear walls and I like to keep them close to each other. My clients review my specs it just helps them focus. Also , as recoginzed by the current Masterformat discussions, Division 9 and 7 are too crowded and Divisins 3,4, 5 & 6 are under utilized. Any chance I can I use one of the latter sections. It would be great if they moved all the plaster and Gyp board work to Div 6, but USG and National Gyp would never let this happen. Jo Drummond New member Username: Jo_drummond Post Number: 11 Registered: 03-2002 Posted on Saturday, August 31, 2002 - 12:42 pm:    I have it in 6, but I sometimes relocate it if I am using it on a building with metal framing. Gerard Sanchis Unregistered guest Posted on Wednesday, September 04, 2002 - 07:30 pm:    My, my, we certainly do not have a consensus on this one. I am surprised by the number of answers, their divergence, and the explanations that they contain. I see no reason for having this material (by the way DensGlas is still gypsum sheathing, contrary to what some of the answers indicate) specified in Division 5 or 6. I'll accept 9, even though its logical location is in 7. Most of the answers make reference to trades and systems. We do not write specs based on either one, but on materials (such as gypsum board) and assemblies (such as curtain wall). As for repeating information that can be found in the gypsum board section, all one has to do is simply to refer back to 09250 without repeating what's there. To muddy the water further, can someone tell me why sprayed insulation in specified in Div 7 and plaster fireproofing in 9? Gerard. John Bunzick, CCS, CCCA New member Username: Bunzick Post Number: 29 Registered: 03-2002 Posted on Thursday, September 05, 2002 - 08:59 am:    Ah, but one could certainly consider the light-gauge framing with sheathing to be an assembly! The logic behind gyp sheathing in Division 6 is that is where all the other sheathing is (generally plywood/OSB etc.) And why not give some consideration to which trade performs the work when there is no concensus on where something belongs? Just because we don't specify around trades specifically, does not mean we should completely ignore that important factor. (Too much of the blind-eye to what happens in the field can be seen as arrogance by the designer. Aren't we supposed to all be on a team?) I think this interesting conversation illustrates something that Dennis Hall recently pointed out, which I had not really grasped until he mentioned it. MasterFormat is NOT a true classification system where everything would naturally fall into its best location. It has lots of anomalies, due in part to its history, including the material vs. assembly dilemma. I think we have just found one such anomaly. Phil Kabza Unregistered guest Posted on Friday, September 06, 2002 - 09:17 pm:    I'm in with Anne in putting Gyp Sheathing in 05400 when used. It's also one of the more FAQs at my desk, so obviously our staff doesn't find that location to be "intuitive." We've moved to almost exclusively specifying glass-mat-faced and typically use an air-barrier wrap over it. It's never made sense to me to put conventional gypsum board inside a damp, concealed cavity. I've heard more than one suggestion about developing a Masterspec Division 7 section for sheathing products and related air- and moisture-barriers. That makes sense to me. And no, I don't think USG or Nat Gyp will control how MasterFormat addresses the classification in the future, though I suspect they would appreciate it if we could come together on this one.