PHONY STONE: Doing the drainage plane
PHONY STONE: Doing the drainage plane
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Our Habbie is doing a set of Craftsmen homes with manufactured-stone veneer on the porch columns.
I recall, but can’t find an article in FHB or JLC about the rot you can get behind this stuff if you think it’s waterproof and don’t have a drainage plane.
How would you detail a porch column base?
The transition from stone to the wood wrap above?
The ToolBear
“I am still learning.” Goya
Replies
Is this the article that you where thinking of?
http://www.jlconline.com/cgi-bin/jlconline.storefront/47f6d15b034ec91127170a32100a0605/Product/View/0412manu
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill -Thanks for the look up. That sounds like it. Now I have to rummage about for that issue of JLC. Got them back into the '90s.The ToolBear
"I am still learning." Goya
The sharpest guys I know who do phony stone are also great at top quality stucco. They simply detail the base coat as if it were stucco. Butting up to wood, they'd stop an edge channel short by 1/4" and caulk the gap. Water managment is really important.
Beer was created so carpenters wouldn't rule the world.
The sharpest guys I know who do phony stone are also great at top quality stucco.@@@I was told to treat it like stucco. I suggested they have a weep screed at the bottom and got some odd looks. There is probably a neat way to insure drainage and maintain that stony look (Why would we want that?)
Because rot sucks?The ToolBear
"I am still learning." Goya
The guy that did that cultured stone aritcle in JLC does the same kind of work with stucco. And also had a Stucco article..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Toolbear,
Be very cautious and conservative in your details; reports of failures involving adhered manufactured stone veneer over OSB are rising. Here is an excerpt from an interview with building scientist John Straube in the March 2008 issue of Energy Design Update:
EDU: Do you agree that stucco and manufactured stone veneer are causing more wet-wall failures than other types of siding?
Straube: Ever since the EIFS industry had its shakeup and developed water-managed EIFS systems, the problems have shifted to direct-applied stucco over OSB and direct-applied veneers over OSB. With these installations, there are some quite spectacular failures. These can be really expensive problems. But these failures are not a surprise -- we would expect to seem them. The solutions are simple -- it’s just a question of getting the word out. The solutions include providing an air gap, or just a 3/4-inch layer of foam and two layers of building paper. With the foam and two layers of paper, you have just reduced your risk by a factor of ten.
EDU: Why do you think that manufacturers of adhered veneer products still haven’t changed their installation recommendations to include these solutions?
Straube: It’s hard to know -- it’s hard to get into the minds of the manufacturers. Even if the rate of failure is high, it takes a while for people to learn. We’re using more moisture-sensitive sheathing and framing materials than we used to. It takes a while for the information to feed back to the manufacturer -- those of us who investigate failures get feedback faster than a manufacturer will. What I think is normal and obvious is far from normal and obvious for many people, because they don’t hear a hundred builders telling them stories. Each of us in the forensic consulting business hears these stories, and then at conferences we talk to each other, while most manufacturers and not part of that network. Bad news travels remarkably slowly.
Thanks for the quote. I have mailed it over to the site super.Wonder how the foam and paper work. I assume there is a metal lath in there somewhere for the mortar to get a grip.The ToolBear
"I am still learning." Goya
Toolbear,
Yes, you still need metal lath; the foam is installed behind the metal lath. The foam does several things:
1. It acts as a capillary break and moisture barrier, helping keep the OSB dry.
2. It acts as a vapor barrier, stopping inward solar vapor drive that occurs when the sun shines on damp siding the day after a rainstorm.
3. It helps insulate the wall.
The JLC Guide to Moisture Control has all the information toolbear needs in chapter 8. Even without the foam, two layer of 60 minute building paper , properly lapped and flashed would provide the protection, along with the bottom edge weeps. Since they are doing porch columns, the foam may may make them to big or clunky looking.
I picked up the book on amazon for $25. Cheaper than the JLC price, but worth it even at the higher cost IMO.
Yes, you still need metal lath; the foam is installed behind the metal lath. The foam does several things:1. It acts as a capillary break and moisture barrier, helping keep the OSB dry.2. It acts as a vapor barrier, stopping inward solar vapor drive that occurs when the sun shines on damp siding the day after a rainstorm.@@@@@@@@@@@@@@@@@@I am reading Building Science's paper on drainage planes and they discussed that heating effect. They were looking at a brick wall, but I suspect this stone is similar to brick in being rather transparent to rain.Found a bunch of installation videos on Cultured Stone's site. Interesting. First thing on was the weep screed, then double layers of paper, etc.How about two layers of 30# paper over the screed.The ToolBear
"I am still learning." Goya