Densglass vs. Exterior Gyp Rock

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Author Message MalcolmYoung (Unregistered Guest) Unregistered guest Posted on Tuesday, April 16, 2019 - 05:49 pm:    Why would you pay more for fiberglass sheathing like Densglass vs. a paper facing exterior sheathing solution? Dewayne Dean Senior Member Username: ddean Post Number: 192 Registered: 02-2016 Posted on Tuesday, April 16, 2019 - 06:16 pm:    On a parapet wall, PVC Roof companies require the fiberglass sheathing Jerome J. Lazar, CCS, CSI Senior Member Username: lazarcitec Post Number: 1984 Registered: 05-2003 Posted on Tuesday, April 16, 2019 - 06:29 pm:    Malcolm, perhaps you should contact the Densglass manufacturer G-P Gypsum (800) 225-6119 www.gpgypsum.com Brian Payne Senior Member Username: brian_payne Post Number: 174 Registered: 01-2014 Posted on Tuesday, April 16, 2019 - 06:46 pm:    Paper. Exterior. Fail. Wayne Yancey Senior Member Username: wayne_yancey Post Number: 893 Registered: 01-2008 Posted on Tuesday, April 16, 2019 - 06:47 pm:    Malcolm, Paperface is food for mold. The paper-face is only water resistant. Unless their is drying capability in the assembly at the paper-face the will not last. The new generation of exterior gypsum sheathings are far superior for water-management. For wall sheathing I specify Glass-Mat Gypsum Sheathing: ASTM C1177/C1177M. I am also spedifying Air-Barrier and Water-Resistant Glass-Mat Gypsum Sheathing: ASTM C1177/C1177M, Type X, coated fiberglass mat gypsum sheathing with integral weather-resistant barrier and air barrier complying with ASTM E2178 For back of parapets I specify G-P Densdeck Prime (Glass-Mat Gypsum Sheathing: ASTM C1177/C1177M). Wayne Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 762 Registered: 08-2005 Posted on Tuesday, April 16, 2019 - 07:07 pm:    Brian said it best, but Malcolm, this question should be directed to your attorney and/or liability insurance broker. I'm sure they will give you sufficent information to be clear on the topic. Also, to Jerome, while true, DensGlass itself is not allowed on the backside of parapets where in contact with roofing, G-P requires DensDeck in that location/use. David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1764 Registered: 03-2002 Posted on Tuesday, April 16, 2019 - 07:12 pm:    Do they still make paper-faced exterior sheathing? David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC Jerome J. Lazar, CCS, CSI Senior Member Username: lazarcitec Post Number: 1986 Registered: 05-2003 Posted on Tuesday, April 16, 2019 - 07:21 pm:    Nathan, you believe Malcolm's attorney and/or liability insurance broker knows the difference. We don't know if Malcolm is an Architect or an Owner. The knowledge of construction possessed by the afformentioned professionals never ceases to amaze me. An attorney is the last professional I would ask for construction material advice. Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 763 Registered: 08-2005 Posted on Tuesday, April 16, 2019 - 07:34 pm:    David, I think PABCO still makes it, I've actually seen recent installations in Mexico during a visit not too long ago. Jerome, excellent point (about who Malcomb might be), but I can confidently say that my attorney is well versed in material failures, having spent 25 years defending architects in SoCal, the land of defective plaster, concrete, and glazing. I spent a decade doing public schools and owner-builder multi-family projects. Litigation is simply the final phase on projects like that. You know: SD/DD/CD/CA/LG. Sad but true.... Jerome J. Lazar, CCS, CSI Senior Member Username: lazarcitec Post Number: 1987 Registered: 05-2003 Posted on Tuesday, April 16, 2019 - 07:59 pm:    Do not specify PABCO, but a visit to their website and I see they now own QuietRock, some of my clients like QuietRock. Don Harris CSI, CCS, CCCA, AIA Senior Member Username: don_harris Post Number: 321 Registered: 03-2003 Posted on Wednesday, April 17, 2019 - 03:37 pm:    Haven't used paper faced sheathing in approximately 20 years. I'm not sure that one can make the argument that one is meeting the standard of care using paper faced sheathing. MalcolmYoung (Unregistered Guest) Unregistered guest Posted on Wednesday, April 17, 2019 - 04:24 pm:    I guess that narrows product choices down to fiberglass based products. I guess the next logical question is whther there is any actual differentiation between fiberglass products. Example (Securock vs. Densglass)? I find it surprising that no one uses paper faced gypsum sheathing for exterior wall sheathing. Its a huge part of the products that GeorgiaPacific, USG, National Gypsum, American Gypsum offer. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 478 Registered: 10-2003 Posted on Wednesday, April 17, 2019 - 07:57 pm:    malcom - maybe the difference is that paper faced gypsum is used in non-architectural projects. There are also regional differences in climate and what facings are applied. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1766 Registered: 03-2002 Posted on Thursday, April 18, 2019 - 02:33 pm:    I was serious when I asked my question to whether paper-faced exterior gypsum sheathing was still manufactured. I NEVER see it out here in the Pacific Northwest. In fact, my local Home Depot does not even stock it. They stock G-P DensGlass Gold! Once paper-face gypsum sheathing is installed it is probably fine (barring no leaks). The problem is putting it up in the rain and having it exposed to the elements before weather barrier and cladding is installed. (I think today will be our 12th day in a row with measurable precipitation here in Seattle.) G-P warrants DensGlass Gold for 12 months of exposure! David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1776 Registered: 03-2002 Posted on Thursday, April 18, 2019 - 04:00 pm:    The selection of many products can be seen as a risk management issue. Does the cheaper product have a higher likelihood of failure, or poor performance? How much will be saved with the cheaper product? How hard is it to fix it if it fails? So paper-based sheathing is only slightly cheaper to install, has a much higher likelihood of failing, and is extremely expensive to replace. This is not a good trade off. Another example, on the other end: a cheap interior paint applied to the gypsum board wall in a fire stairs. It fades in a few years, but is simple enough to repaint. Or maybe the client repaints every few years regardless. That may make it worthwhile for the client. MalcolmYoung (Unregistered Guest) Unregistered guest Posted on Thursday, April 18, 2019 - 04:15 pm:    How much of the market is still using paper faced gypsum then with all of these concerns? David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1767 Registered: 03-2002 Posted on Thursday, April 18, 2019 - 09:50 pm:    I took a site tour of a high rise in construction put on by my local chapter of CSI. I noticed that that all the gypsum board was paperless mold-resistant products but changed to typical paper faced gypsum board products deep in the building. I asked the contractor and he said until the curtain wall goes up most of the interior walls will get rained on. He said it was cheaper to install that board than redo weather ruined gypsum board. David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 1448 Registered: 07-2002 Posted on Thursday, April 25, 2019 - 08:51 pm:    Because more and more of our contractors are unwilling to dry-in the building, we are using more fiberglass faced boards for interior work too -- the interior face of the exterior wall and around the core. I require the building to be enclosed (ie, sealed up) before the installation of paper faced boards (and this is per the GA requirements); but will allow fiberglass faced boards at no additional cost if the contractor wants to use them to progress the schedule. In our area, fiberglass is slightly more expensive to install and finish (about 5%) so that's the premium the GC has to pay to not enclose the building. They always take that option. David E Lorenzini Senior Member Username: deloren Post Number: 182 Registered: 04-2000 Posted on Tuesday, June 04, 2019 - 06:00 pm:    Does anyone know of problems with Pabco gypsum board products? Specifically Mold Curb Plus Type X to be used for office interior ceilings? David Lorenzini, FCSI, CCS Architectural Resources Co. Nathan Woods, CSI, CCCA, LEED AP Senior Member Username: nwoods Post Number: 772 Registered: 08-2005 Posted on Tuesday, June 04, 2019 - 06:24 pm:    David, PABCO has a large plant in Las Vegas, which makes them a local commodity here in SoCal. I have certainly seen pallets of it on numerous jobsites here in SoCal over the years. They appear to be a solid product, sold at a discount compared USG and GP. I have not had any negative experiences with them Ed Storer Senior Member Username: ed_storer Post Number: 25 Registered: 05-2009 Posted on Sunday, September 01, 2019 - 01:11 pm:    I have never specified paper-faced gypsum sheathing since 1986. Once I understood the benefits of fiberglass facing and siliconized core. There was no doubt for me. I've had difficulty with using fiberglass faced gypsum board and the interior. The fiberglass surface is not as smooth as paper and getting a paint system that will look like the finish on a paper-faced gypsum board has no "support" from either the gypsum manufacturer or the paint manufacturer. Phil Kabza Senior Member Username: phil_kabza Post Number: 634 Registered: 12-2002 Posted on Tuesday, September 03, 2019 - 02:35 pm:    Same issues as Ed mentions. We spec the mold and mildew resistant boards such as National Gypsum's XP Board for wet areas and for areas finished prior to enclosure. Clients have complained about the appearance of fiberglass mat-faced board on the interior when receiving paint but no skim coat. James Sandoz, AIA, CSI, CCS, CCCA Senior Member Username: jsandoz Post Number: 279 Registered: 06-2005 Posted on Wednesday, September 04, 2019 - 08:39 am:    I agree with Phil. The only way I've seen to get a satisfactory painted finish with glass mat faced gypsum board is to specify a skim coat of joint compound over the entire surface - in short, a Level 5 finish according to ASTM C840, GA-216, and GA 214. $$$ Of course, a skim coat is not necessary if the glass mat faced gypsum board is a substrate for a panel product.