Thread: Stone and Stucco junction

Whenever I have seen hardcoat stucco and stone veneer installed together there typically is flashing between the two materials. The flashing is up under the stucco and terminates about 1/4-1/2" on top of the cap stone and no caulking is present to allow for drainage. Does anyone have detailed drawings showing a proper installation?

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What type of wall construction: masonry or frame?

These are two completely different systems and both terminate differently.

Originally Posted by Richard Roshak

Whenever I have seen hardcoat stucco and stone veneer installed together there typically is flashing between the two materials. The flashing is up under the stucco and terminates about 1/4-1/2" on top of the cap stone and no caulking is present to allow for drainage. Does anyone have detailed drawings showing a proper installation?

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Try Here Architectural Details and Drawings for stucco applications
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Originally Posted by Billy Stephens

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Try Here Architectural Details and Drawings for stucco applications
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A quick glance through some of those details indicates they are all for frame construction, which has not yet been stated.

Originally Posted by Jerry Peck

A quick glance through some of those details indicates they are all for frame construction, which has not yet been stated.

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If Richard can't use the attachment ( Maybe Someone else can.)
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Both the stucco and the stone should be installed on a integrated system. To start with the stone you first install a double D felt paper with correctly lapped seams. You then install expanded metal lath. Next you install your scratchcoat which you install the stone to that after it has dryed. Now for the stucco, after the scratch coat,you install the brown coat then the finish coat. all terminations in stucco can no longer be free floated. All terminations must be done with a metal J-BEAD or weep screed. A caulked seam there would show an incorrect termination. The stucco should be terminated with a J-BEAD/CASING BEAD 3/8" above the stone veneer with with a flashing behind the WRB on the wall and on top of the stone with positive drainage and no caulk.

P. Phillips

Originally Posted by Paul Phillips

Both the stucco and the stone should be installed on a integrated system. To start with the stone you first install a double D felt paper with correctly lapped seams. You then install expanded metal lath. Next you install your scratchcoat which you install the stone to that after it has dryed. Now for the stucco, after the scratch coat,you install the brown coat then the finish coat. all terminations in stucco can no longer be free floated. All terminations must be done with a metal J-BEAD or weep screed. A caulked seam there would show an incorrect termination. The stucco should be terminated with a J-BEAD/CASING BEAD 3/8" above the stone veneer with with a flashing behind the WRB on the wall and on top of the stone with positive drainage and no caulk.

P. Phillips

Great first post!

Originally Posted by James Duffin

Great first post!

It was, except that only applies to frame construction and we have not heard back from the original posters as to whether that is a frame wall or not.

A whole lot of assumptions going on here without inclination to wait for clarification of the type of structure.

That's like having an auto repair garage and someone brings a car in and you start by filling the tank with gas because it was empty ... only to find out that it was diesel ... guys, take a breather, wait until you know what kind of structure it is before you start to dissect it and try determine what is wrong ...

It is wood framing. There are about 50+ homes with the stucco/stone installed in this manner. The homes are about 1 year old. Smells like a lawsuit to me.

Rich,
you definitetly want to see a break of weep screed at foundations and really I find every 8 feet up a wall is best moisture management. Here are some pictures of weep break in walls and foundations, note we used a flashing detail to shadow the stone on the foundation due to the framing over hang, just a cleaner approach.But you should see horizontal lines of componants at foundations or at breaks between the solid flat stucco surface or the stone embellishment.

we use a piece of VYCOR at the bottom with the weep installed over it, the 2 WRB's lay over the entire componants. I would be very careful with the 2 layers of black felt paper, throw an infrared or thermal scanner on a southern exposed wall in the summerand tell me the temperature of the wall,these one coat systems are still working their way out of the woods with a lot of stuff yet, same with the rainscreen, the Japanese are ahead of us with that failure, I see so many architects and engineers on that band wagon

Nice work. But, I wonder how soon someone will cut off the "ugly" projecting flashings...

Hopefully not too soon...If the architects designed walls to ASTM 1063 you would see this or something similar on all walls. flashing was never designed to be pretty.

I would clarify my statement on weeps every 8 feet, more like at the foundation line, the second floor plate line and the top plate line at the roof rafters or truss elevation. I see a lot of gable control joints ripped apart at the roof truss bottom chord due to movement and poor connections at the plate line as shown in this photo after everything was removed from the wall.

Originally Posted by Jerry Peck

It was, except that only applies to frame construction and we have not heard back from the original posters as to whether that is a frame wall or not.

A whole lot of assumptions going on here without inclination to wait for clarification of the type of structure.

That's like having an auto repair garage and someone brings a car in and you start by filling the tank with gas because it was empty ... only to find out that it was diesel ... guys, take a breather, wait until you know what kind of structure it is before you start to dissect it and try determine what is wrong ...

GEE! sounds like someone I know.

Originally Posted by tabatha ness

... Stucco is applied using black paper, lath, scratch coat, basecoat and than finish. It is a hard coat system that could not weep moisture. When the stucco is applied over the lath the scratch coat goes into the holes of the lath. It isn't supposed to be a moisture weep system...

You're saying that conventional stucco over wood frame is not supposed to be a moisture weep system?

Originally Posted by John Arnold

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You're saying that conventional stucco over wood frame is not supposed to be a moisture weep system?

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Sounds as if we have another Mueller Field Rep.
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Originally Posted by tabatha ness

... This is utilized when an architect doesn't want to see the flashing or plastic track.....

He may not want to see it
but
required flashing
is required....

Originally Posted by tabatha ness

Stucco is applied using black paper, lath, scratch coat, basecoat and than finish. It is a hard coat system that could not weep moisture. When the stucco is applied over the lath the scratch coat goes into the holes of the lath. It isn't supposed to be a moisture weep system.

So you are the one responsible for all those rotted out walls behind stucco lath installed without a drainage plane? I always wondered who the culprit was.

You left out one VERY ... V-E-R-Y ... IMPORTANT ... I-M-P-O-R-T-A-N-T step: namely the drainage plane.

Stucco on wood frame needs a drainage plane. That drainage plane could be 30# felt (although that is not necessarily the best material to use as a drainage plane as it soaks up moisture). The drainage plane could be house wrap, Tyvek makes a special house wrap for use behind stucco, it has 'dimples' (for lack of a better term) in it and the rows of dimples are intended to be installed vertically (when the Tyvek is installed horizontally around the house), and those dimples create a drainage plane.

Then ... and only then, do you install the 15# or 30# felt and metal lath, or paper backed metal lath.

The paper on the paper backed metal lath (or the 15# or 30# described immediately above) serve as the bond breaker between the stucco and the drainage plane. The stucco is 'scratched' (forced into the openings in the expanded metal lat) and that stucco which goes through the openings create 'globs' or 'keys' behind the metal lath are hold the stucco to the metal lath. The stucco is scratched in and pressed against the paper described in this paragraph, and this paper simply serves as a bond breaker so the stucco does not bond to the house wrap which was installed first.

Then the brown coat (the 2nd coat), then the finish coat (the 3rd coat). By the way, the MINIMUM thickness for standard 3-coat stucco on frame is 7/8", not 3/4".

See, stucco *is not water proof*, I would not even want to call it 'water-resistant' as water goes through stucco, the water goes through the stucco, goes through the bond breaker paper, then weeps down the back side of the bond breaker paper between it and the house wrap on the wall behind the bond breaker paper.

That water is required to have a weep screed installed which directs the water out from behind the stucco and out from within the wall. There are two basic locations for weep screeds and the two weep screeds are different, not to be used in the wrong location.

1) Foundation weep screed, this is designed to be used where the frame wall sets on the foundation.

2) Intermediate weep screed, this is designed to be used a frame second story wall (for example) sets on a concrete block first story wall.

There are two basic types of foundation weep screeds:
1) Perforated, this has the holes in the upper sloped surface.
2) Non-perforated, this has no holes in the upper slope surface.
- Contrary to what many think, the holes have nothing to do with weeping the water out. All the holes are there for is to allow the stucco to be pushed into those holes and to key the stucco into the weep screed, this only serves to hold the stucco to the lath and the weep screed.

Exterior stucco needs to be painted to make it water proof. It also requires a code approved vapor barrier underneath if its installed on wood frame construction. Exterior stucco consist of a scratch coat and a finish coat. Some may install an intermediate coat. The scratch coat is ussually 3/8ths to 1/2 inch thisk and the finish coat is the same thickness depending on the texture required. I have even seen the finish coat sprayed on. They used to mix perlight with the stucco and spray it on the scratch coat.

Exterior stucco does not have a brown coat. Only interior plaster on rock lathe has a brown coat and a finish white coat that should be 3/4 of an inch thick on non FHA homes and 7/8 of an inch on FHA homes. Thats old school from the 50's and 60's. FHA homes required 7/8 plaster grounds around doors and base boards. We used to buy 1x3 syp that was 7/8ths of an inch thick. I'm getting old!

Stucco is very common here, especially on houses pre-1930. I see lots and lots of stucco on these older homes that borders on brick or stone veneer, with no flashing or space for drainage where they meet. Most of the time there don't seem to be any problems associated with it. Why is it that newer homes apparently need so much extra protection?

Maybe it's a regional thing? In areas that don't usually get rain for days or weeks on end, perhaps the small amount of water absorbed by the stucco evaporates during the next sunny period, and doesn't collect behind it? Just an idea.

Originally Posted by Richard Burkard

Exterior stucco needs to be painted to make it water proof. It also requires a code approved vapor barrier underneath if its installed on wood frame construction. Exterior stucco consist of a scratch coat and a finish coat. Some may install an intermediate coat. The scratch coat is ussually 3/8ths to 1/2 inch thisk and the finish coat is the same thickness depending on the texture required. I have even seen the finish coat sprayed on. They used to mix perlight with the stucco and spray it on the scratch coat.

Exterior stucco does not have a brown coat. Only interior plaster on rock lathe has a brown coat and a finish white coat that should be 3/4 of an inch thick on non FHA homes and 7/8 of an inch on FHA homes. Thats old school from the 50's and 60's. FHA homes required 7/8 plaster grounds around doors and base boards. We used to buy 1x3 syp that was 7/8ths of an inch thick. I'm getting old!

Richard,

Not sure where you are getting your information on "stucco" from, but the rest of us, at least most of the rest of us, are talking about, and referring to, the real stuff "stucco" (which is also known as exterior plaster) which is addressed by ASTM C926, and ASTM C926 states: (bold and underlining are mine)
- 7.2 Plaster Application on Metal Plaster Bases:
- - 7.2.1 The first (scratch) coat shall be applied with sufficient material and pressure to form full keys through, and to embed the metal base, and with sufficient thickness of material over the metal to allow for scoring the surface.
- - - 7.2.1.1 As soon as the first (scratch) coat becomes firm, the entire surface shall be scored in one direction only. The vertical surfaces shall be scored horizontally.
- - - 7.2.1.2 The first (scratch) coat shall become sufficiently rigid to support the application of the second (brown) coat without damage to the monolithic continuity of the first (scratch) coat or its key.
- - 7.2.2 The second (brown) coat shall be applied with sufficient material and pressure to ensure tight contact with the first (scratch) coat and to bring the combined thickness of the base coat to the nominal thickness shown n Table 4.
- - - 7.2.2.1 The surface of the second (brown) coat shall be brought to a true, even plane with a rod or straightedge, filling surface defects in plane with plaster. Dry rodding the surface of the brown coat shall be permitted.
- - - 7.2.2.2 The surface shall be floated uniformly to promote densification of the coat and to provide a surface receptive to bonding of the finish coat.
- - 7.2.3 The third (finish) coat shall be applied with sufficient material and pressure to ensure tight contact with, and complete coverage of the base coat and to the nominal thickness shown in Table 1 and 7.3.1.1.

TABLE 1 states the nominal plaster thickness, talking about stucco on metal lath on frame, at 1st coat = 3/8", 2nd coat = 3/8", and 3rd coat = 1/8", total = 7/8".

Table 1 also addresses the nominal plaster thickness on solid plaster base, such as on concrete masonry blocks, and that either two-coat or three-coat work can be done, instead of the three-coat work required for stucco on frame (shown above). On solid plaster bases the thicknesses are:
- two-coat work 1st coat = 3/8" and the finish coat = 1/8" for a total of 1/2"
- three-coat work 1st coat = 1/4", 2nd coat = 1/4", third coat = 1/8", for a total of 5/8"

The above are for vertical surfaces.

Your information does not correspond with the above information - what is the source of your information?

Kristi

Seeing this post reminds me I needed to get back with on my seminar you asked me about. It is not set up yet but I will let you know.

Now for your post here.

The older homes were built with old growth timbers and lumber that is more dense and less absorptive of moisture. Couple this with the fact that often there was not insulation in the wall cavity and that they were not sealed near as tight gives the wall breath-ability so it can dry. As long as the wetting does not exceed the drying then you see very little problems.
The newer construction uses much more moisture sensitive materials, seals them up and put moisture retaining sponges in the walls (insulation). This is not a bad thing but you need to detail to keep the sponge dry. This can be done but it's not always up on contractors important list of things to do.
On a lot of the older stucco jobs there is a double layer of paper that creates a drain plane. As the base coat was applied this would crinkle the outer layer of paper and create a little drainage path between it and the second layer of paper. This would drain at the weep screed at the bottom of the assembly. Any moisture that got by this second layer of paper would be minimal and run into a wall cavity that had drying potential. When we started insulating the walls and started using materials that were much more sensitive to moisture the problems started happening. The building envelope sealing details became much more important.

These are not stucco covered assemblys but moisture got behind the exterior cladding and wreaked havoc just the same.

Originally Posted by Kristi Silber

...Why is it that newer homes apparently need so much extra protection?...

BSI-029: Stucco Woes—The Perfect Storm — Building Science Information

Hi Mark! Why don't you come up to Minnesota to give your talk?

Moisture behind stucco: Yes, I see, how interesting! So, even if the old houses are insulated, their walls are thinner, no vapor barrier, and plaster instead of drywall, so moisture doesn't get trapped in the wall so easily. I didn't think about it moving into the home, but that makes sense.

That cantilever shot is scary. Does the last photo show holes of powder post beetles? Or what makes those holes?

John, that is an excellent article. Fascinating expansion on what Mark said. The "solar induced drive of moisture" was intriguing, will have to think about that. I'd wondered how modern WRB compared to paper. That looks like a site I could spend lots of time exploring.

Thanks, guys!