| Author |
Message |
(Unregistered Guest)
Unregistered guest
| | Posted on Wednesday, June 29, 2005 - 12:33 pm: |    |
Writing a spec for gypsum plaster for an interior monumental stair enclosure - what should the substrate be? We have not had recent experience with gypsum plaster specs - any one able to provide some insight would be appreciated. |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 408
Registered: 10-2002
| | Posted on Wednesday, June 29, 2005 - 01:55 pm: | |
There is a wonderful little book ('paper back novel' size format) that is a great reference for plaster and drywall and covers all kinds of applications and substrate conditions. USG produces it and has for many, many years. It is titled "Th eGypsum Construction Handbook"
It talks about products as well as different methods of installation. All kinds of plaster systems are well discussed and refrenced to their own product l ines. But even without their product refrences, it is about the best single reference source I have come across.
William |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 48
Registered: 11-2004
| | Posted on Wednesday, June 29, 2005 - 02:41 pm: | |
<nodding in agreement with William>... and it is available online at www.usg.com |
Jo Drummond, FCSI
Senior Member
Username: jo_drummond
Post Number: 15
Registered: 01-2005
| | Posted on Thursday, June 30, 2005 - 08:37 pm: | |
Typically, traditionally, gypsum plaster can go over gypsum lath, perforated or unperforated, in 2 coats, or over metal lath in 3 coats. It is available in various hardnesses: Keene's cement, hard, being the hardest I know of.
Gyp lath is rarely used. 13 years ago, I built an addition to my house which is lath and plaster, and I insisted on the addition being the same. When the lathers came in, they put up perforated gyp lath, and put one nail in each corner, announcing that they would send an apprentice to do the rest of the nailing. As they spoke they added: He has never seen this material before. Usually he does drywall. So it doesn't happen every day, but it is still there if you want it.
A contractor will probably try to talk you into veneer plaster. But if you have curves, nothing will be as smooth and uniform as Gyp Plaster over metal lath. |
Ron Beard CCS
Senior Member
Username: rm_beard_ccs
Post Number: 62
Registered: 10-2002
| | Posted on Friday, July 01, 2005 - 12:32 am: | |
FYI; from the latest CSINewsBrief:
"Best Practices
Designers put plaster back on its pedestal
After falling out of favor with designers, plaster walls are making a comeback, with traditional full-coat, as well as one-and two-coat veneer plaster wall systems particularly popular. Some designers like the monolithic look that can be achieved with plaster, but the versatility in texture and long-term durability are also popular features, an expert says."
< http://www.buildings.com/Articles/detailBuildings.asp?ArticleID=2526> |
Tracy Van Niel
Senior Member
Username: tracy_van_niel
Post Number: 122
Registered: 04-2002
| | Posted on Friday, July 01, 2005 - 09:39 am: | |
Depending on what your monumental stair looks like, you might even consider using two layers of 1/2 inch gypsum board and skim coating the entire surface (like for a level 5 finish). We were considering using gypsum plaster in a high quality level boardroom on a barrel type ceiling. The contractor we talked to about the ceiling suggested that we might consider the two layers of 1/2 inch gypsum board with the skim coat instead of the gypsum plaster system so that's what ended up getting specified. It turned out great and was a less expensive system as well. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 94
Registered: 05-2004
| | Posted on Friday, July 01, 2005 - 11:52 am: | |
I have used veneer plaster in Georgia, Hawaii, and Texas for more than 35 years. It is possible to get smooth curves with veneer plaster, you just have to get the right mechanic. I would suggest that if you can't get the level of work you are looking for in "standard" plaster work on metal or gypsum lath, you probably won't get it with veneer plaster.
Several people have mentioned veneer plaster over "gypsum board". The most correct term, I believe, is veneer plaster base. This has a blue paper facing which is designed to go with the veneer plaster finish. If you use one of the other gypsum board products (backing board, regular board, or MR board), you will not get the same performance (or the same backup from the veneer plaster manufacturer when something goes wrong). All of this is documented in the above cited references.
I had a situation about 5 or 6 years ago where the Contractor was having a hard time getting "blue board." The installer proposed using regular gypsum board with some sort of adhesive/bonding agent applied over the board before application of the plaster. When I asked the USG rep about this, there was one of those long pauses at the other end of the phone and a deep breath before a strong recommendation that this option not be taken. |
John Bunzick, CCS, CCCA
Senior Member
Username: bunzick
Post Number: 374
Registered: 03-2002
| | Posted on Tuesday, July 05, 2005 - 09:04 am: | |
Veneer plaster is extremely popular here in New England for a superior finish. It is even commonly used in home renovations--like my kitchen--at least in part because of speed. (In my house, two rooms and a stairwell were done in two days: one to hang rock, one to plaster. I used to use it in supermarket renovations where an entire remodel project could be accomplished overnight. No repeat trips for sanding etc.) Peter is correct, with veneer plaster, you must use veneer plaster base or the system will fail. I also agree with Peter, you need the mechanics to do a good job. Maybe there's some plasterers here in New England who'd like a trip to wherever that project is... |
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