Why would you pay more for fiberglass sheathing like Densglass vs. a paper facing exterior sheathing solution?
On a parapet wall, PVC Roof companies require the fiberglass sheathing
Malcolm, perhaps you should contact the Densglass manufacturer
G-P Gypsum (800) 225-6119 www.gpgypsum.com
Paper. Exterior. Fail.
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
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.
Do they still make paper-faced exterior sheathing?
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.
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…
Do not specify PABCO, but a visit to their website and I see they now own QuietRock, some of my clients like QuietRock.
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.
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.
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.
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!
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.
How much of the market is still using paper faced gypsum then with all of these concerns?
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.
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.
Does anyone know of problems with Pabco gypsum board products? Specifically Mold Curb Plus Type X to be used for office interior ceilings?
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