| Author |
Message |
Robin E. Snyder
Senior Member
Username: robin
Post Number: 24
Registered: 08-2004
| | Posted on Tuesday, August 02, 2005 - 11:43 am: |    |
I have a client that wants to use stucco on a 20 story building. In Las Vegas, we typically use EIFS. What are the good, bad and ugly factors to consider when using Stucco on a steel-frame high rise? |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 437
Registered: 10-2002
| | Posted on Tuesday, August 02, 2005 - 12:00 pm: | |
Robin,
We have done stucco on high rise projects, though typically in the 8 to 15 story heights. Areas we do this are in the Dallas region of Texas and in the Washington DC area.
What I recommend is that you don't specify the stucco as a kit of parts like plaster, but that you actually specify a manufacturer's specific system (and if you need more than 1 mfr listing, there are several out there that make equivalent products).
What I recommend that you do is go to a manufacturer of reputation that provides good quality information and has good tech support - preferrably in person or at least by email. Though I specify more than 1 product at times, when I am investigating an area that I have little experience with personally on Stucco, I have found working with Parex to be the most responsible. They have a great web site. Going there it divides between EIFS and Stucco. You can learn a lot there, but you really need to talk to someone about how all the products can come together to make a system, warranty, etc. The Parex people can do that - and they are not a 'hard sell' type rep. They have dedicated technical support people.
Email me and I will give you a direct contact with them if you wish.
wpegues@wdgarch.com
William |
Anne Whitacre, CCS CSI
Senior Member
Username: awhitacre
Post Number: 227
Registered: 07-2002
| | Posted on Tuesday, August 02, 2005 - 12:38 pm: | |
the biggest issue you will have with stucco on a taller facility is the racking from wind at the corners and the higher floors. You will need to really stiffen up the frame to prevent that. I would recommend talking to the local Lathing and Plastering Bureau (and there is one in Nevada) about the stiffness required at various locations.
Also: make sure you have enough construction joints: break the areas into approximate squares, have no re-entrant corners; and have comparable substrates under each portion.
Make sure the system is well weeped and drained; you should be using minimum 7/8" system reinforced with fiberglass shorts, and have a good lath with "teeth" to hold the system together.
I personally have not had good luck with the "systems" and don't trust them. I do better with the industry bureaus and their technical reps.
http://www.clpcabureau.org/ this is the Sacramento Lathing and Plaster Bureau; they can probably provide a reference to the local Nevada one. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 136
Registered: 05-2003
| | Posted on Tuesday, August 02, 2005 - 12:58 pm: | |
Stucco Info Sources:
Its worth purchasing and reading the publications on the following sites:
http://www.metallathinfo.com/aboutbook.htm
http://www.cement.org/stucco/
Also, one of the authorities on stucco is Jim Gulde, one of his articles can be found at:
http://www.wconline.com/CDA/ArticleInformation/features/BNP__Features__Item/0,3299,118997,00.html |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 137
Registered: 05-2003
| | Posted on Tuesday, August 02, 2005 - 01:15 pm: | |
Anne - don't you have a problem using fiberglass fibers due to the high alkali content of stucco, we typically specify 100% virgin homopolymer fibers? |
Anne Whitacre, CCS CSI
Senior Member
Username: awhitacre
Post Number: 228
Registered: 07-2002
| | Posted on Tuesday, August 02, 2005 - 02:16 pm: | |
Jerome:
I haven't heard of any problem with the "fiberglass shorts" in our area or on our California jobs. I'll ask around now that you mention it, though. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 138
Registered: 05-2003
| | Posted on Tuesday, August 02, 2005 - 03:20 pm: | |
Anne - Florida stucco tends to be highly alkaline and we have been told that fiberglass fibers will disintegrate. So as long as you specify alkali-resistant glass fibers complying with ASTM C 1116 you would be ok. Its amazing how many contractors in FL try to take fiber out of the spec as a VE item, we find it is an important part of our polymer modifed fiber reinforced stucco spec that we use for high rise work in Florida and the SE. We've done several 40+ buildings in Vegas, all with EIFS, none with stucco. |
Dennis Hall (Unregistered Guest)
Unregistered guest
| | Posted on Monday, August 08, 2005 - 05:37 pm: | |
We have investigated failures of stucco installations in high-rise projects. First, stucco leaks. Second, windows leak. Third, if you don't design/specify for one and two, so will your wallet.
As the old addage goes, "you get what you inspect, not what you expect." A good design is often not properly executed. If the building is not water tight before the stucco goes on, it certainly will not be water tight afterwards. Require testing to assure water tightness.
The list could on on, but if you don't get the water tightness issue resolved (the biggie), the rest does not matter. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 144
Registered: 05-2003
| | Posted on Monday, August 08, 2005 - 07:10 pm: | |
We need some stucco experts - Harry Rourke is either retired or very sick, Jake Ribar, it seems is still kicking: http://www.cement.org/masonry/cc_fn_workable_mortar.asp#
and Jim Gulde is busy investigating hurricane damage in FL from last year - any one else know who's who in stucco? |
Wayne Yancey
Senior Member
Username: wyancey
Post Number: 41
Registered: 05-2005
| | Posted on Tuesday, August 09, 2005 - 11:47 am: | |
Dennis Hall is right on target.
Stucco is a face sealed or concealed barrier system. A good design should incorporate a drained cavity/rainscreen system for all walls, whether it be low-rise, mid-rise, or highrise.
You may say it does not rain in Las Vegas, but it does, and when it does it can be of biblical proportions. Not like the constant annoying drizzle we experience in the Pacific Northwest from time to time (40" per year in Seattle).
Rainwater management is everything whether it be stucco or EIFS or metal cladding.
Water will infiltrate any system. The water must be directed out.
This approach has deisgn implications because rainscreen systems require thru-wall flashings at every floor level and can extend up to 2 floors if drainage cavity is maintained. Head flashings with end dams are required at windows, doors, and similar large openings in walls.
The steel-frame (structural?) and backup framing must be engineered to mitigate deflection in the stucco cladding. Perhaps additional expansion control joints in the stucco are required?
Wayne |
Anne Whitacre, CCS CSI
Senior Member
Username: awhitacre
Post Number: 232
Registered: 07-2002
| | Posted on Tuesday, August 09, 2005 - 12:51 pm: | |
Wayne: I disagree that stucco is "face sealed". 1" thick stucco is a cementitious product that absorbs some water and slowly releases it in the way that other cementitious or clay products does that. I agree it must be weeped and/or drained from the back, in the same way that we weep and drain face brick. However, the primary difference between the EIFS products and real stucco is that EIFS always used to operate on the principle that they were putting a plastic bag on the building, and we know that just doesn't work. Stucco works because it never operated that way.
We do have a design fiction that one can get huge uninterrupted expanses of stucco.. and perhaps that still is possible when it is applied over 18" thick adobe block that won't move; but applied over a steel frame and minimal backup, stucco needs a lot of construction joints to function properly.
It is true that in Seattle it not only stays wet, but stays wet for a long time. IN the southwest, not only are the rains of biblical proportions, but they are often followed by bright sunshine, and drying winds that help dry the cavity in a way that we seldom see on the Pacific side of the Northwest. The cavity must be kept clear in those climates in order to facilitate evaporation. The issues are different however: in Seattle we worry more about seepage and saturation; in Las Vegas and Tucson, we are concerned about keeping the water out during the rain itself, as the climate will generally take care of the drying afterwards. |
Dennis Hall (Unregistered Guest)
Unregistered guest
| | Posted on Thursday, August 11, 2005 - 09:33 pm: | |
Our work indicates that stucco leaks perdominately at control joints, penetrations such as windows and doors, and at the perimeters such as corner joints and coping.
Substrate is critical in a stucco design. If you use metal studs, you have serious challenges. Lath installation is also very important and includes attachment of the lath to the substrate, lapping, direction of the lath, and joint design.
I agree with Anne on using the 3 coat stucco. The so-called "one-coat" stuff is a great opportunity for you to spend quality time with your attorney and professional insurance agent. |
Anonymous
| | Posted on Friday, August 12, 2005 - 05:22 pm: | |
BTW - was just asked to evaluate a proprietary system, which one poster recommends, for a large penthouse (mechanical equipment enclosure) at the top of a 34 story building. Reading through the manufacturer's literature on the system reveals that the system is NOT intended to be used for anything other than lowrise construction. Phoning the manufacturer's technical rep at HQ got me "we can let you apply this on the 34th story even if the literature says otherwise" to which I responded that the only way I would consider this is with something in writing from the manuufacturer stating that application on the high rise was OK and would not void the warranty (a materials warranty, not performance - big whoop), to which he responded no way and added that if the design pressure were 44psf or more, forget it altogether.
We are probably not going to go with the "warranted" proprietary system. |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 449
Registered: 10-2002
| | Posted on Sunday, August 14, 2005 - 01:50 pm: | |
Anon,
And so which kind of system was it - 3-coat, 1-coat, polymer modified, no modified, what kind of finish coating over it all?
Several manuafcturer's provide a specific system for each variety - some are inappropriate for some conditions.
Some systems are low rise only, some not. But working with a manufacturer for a system did have its value to you even there. You found that that particular system from that particular manufacturer was not appropriate - a good point to take back to your owner (or whoever it was requested you evaluate it).
If a manufactuer won't warrant (even for materials only) a system in a specific application, and you won't then use their system, wouldn't you be less inclinded then to use a generic menu if items that are not a system at all? Especially if this were condo work - even if it is for an equipment enclosure.
William |
Anonymous
| | Posted on Monday, August 22, 2005 - 02:07 pm: | |
system is a well known EIFs manufacturer's direct applied system - acrylic synthetic stucco over cement board.
because the manufacturer's literature specifically states that the system is to be used ONLY for lowrise buildings, has a mx recommended PSF of 44, and is expected to crack at cement board joints, a backdrained, 3-coat traditional portland cement plaster system seems a better choice to me. No warranty on that either, but also none of the stated problems from the DEFs.
We had a backdrained. pressure equalized EIF system specified to begin with, fully warranted on a highrise, but the Owner saw EIFs and instructed to use plaster.
Crazy. |
Wayne Yancey
Senior Member
Username: wyancey
Post Number: 50
Registered: 05-2005
| | Posted on Tuesday, August 23, 2005 - 12:02 pm: | |
Anne,
RE: Face Seal or Concealed Barrier
The terminology varies a bit based on geography. Stucco applied directly over a WRB is typically called a face sealed system in Vancouver BC. However here in the PNW, the industry typically terms this a concealed barrier system. We distinguish between the two in our local practice by the approach to the drainage plane. If the system is detailed to provide for drainage, however limited, we would call this a concealed barrier. If no attempt is made to provide for drainage, we would consider this a face sealed system.
Wayne |
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