| Author |
Message |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 737
Registered: 05-2003
| | Posted on Tuesday, April 26, 2011 - 11:31 pm: |    |
I'm looking for current and new methods to treat the perimeter of CBS exterior wall openings. These openings will be filled with windows, doors, grilles, louvers, etc. The work is predominantly in the Southeast, and primarily in Florida. Should these openings receive waterproofing prior to receiving an application of 3 coat Portland Cement Stucco and if so, how? Your responses will be greatly appreciated. |
Gerard Sanchis
Senior Member
Username: gerard_sanchis
Post Number: 20
Registered: 10-2009
| | Posted on Wednesday, April 27, 2011 - 12:15 am: | |
Jerome,
Your question brings up more questions before an answer can be given:
Where is the window located in the opening (recessed, flush with the exterior plane of the wall, somewhere in between)?
Are you planning on a 2- or 3-coat plaster, and is it applied on a parge coat or on lath? How is the wall waterproofed and where is the waterproofing membrane (outboard or inboard)?
What did you have in mind for the waterproofing membrane – fluid-applied, cementitious, peel-and-stick?
Do you intend to provide a waterstop at the sill and a sill pan? |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 738
Registered: 05-2003
| | Posted on Wednesday, April 27, 2011 - 12:28 am: | |
Gerald, as mentioned it is a 3-coat stucco application, we do not use metal lath (corrodes too fast) and PVC lath sparingly, we prefer to require the Contractor to clean the masonry prior to application (seldom done, GC would rather slap on a bonding agent that usually fails). The window location in the opening can be all three you list. The question of waterproofing is what I am looking for, most of the products we spec are ignored by the GC and the result is stucco failure, so we are looking for options and we are curious what our peers are using. |
Gerard Sanchis
Senior Member
Username: gerard_sanchis
Post Number: 21
Registered: 10-2009
| | Posted on Wednesday, April 27, 2011 - 08:54 pm: | |
We seldom if ever have the condition you describe in SoCal, but if you direct-apply plaster to CMU, the only choice you have, to my knowledge, is a cementitious waterproofing; anything else and you will need lath.
Why can’t you exercise more control over what’s specified? You mention that the GC ignores the specs. That can spell trouble for your firm when the building leaks.
The detailing of the window opening has to be carefully done and then enforced in the field. The condition you describe is difficult to make watertight when you get the rains you do in Florida.
As for the lath, you can use stainless steel (Type 316L) or plastic lath; they won’t corrode. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 739
Registered: 05-2003
| | Posted on Wednesday, April 27, 2011 - 10:06 pm: | |
Gerald that is exactly what we use, cementitious waterproofing and plastic lath, we were interested in other solutions or maybe newer products that are on the market that our peers are successfully using in this application. Last year one of our clients ignored our specs and approved the use of a product called Wet Flash (we refused to specify Wet Flash for this application). Of course there were many problems that required all the Wet Flash product to be removed. WE are working on another project for the same client, once again they want us to explore other options, so we are exploring. |
Lynn Javoroski CSI CCS LEED® AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1243
Registered: 07-2002
| | Posted on Thursday, April 28, 2011 - 09:28 am: | |
BASF has PermaLath 1000; it's glass fiber, not PVC (as near as I can tell in the product literature).
I spec'd it for a project near the ocean in CA because of the corrosion issue, but the rest of the stucco system was pretty standard - sheathing, waterproofing, flashings at openings, etc.. |
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