O.K. Here will we go.
Finished the stucco about 6 wks. ago. Today, blisters in a few locations.
Construction is 2×6 frame, 1/2″ ply, tyvec, concrete block, 1″ styrofoam, scratch, mesh, finish. Entire system is Dryvit.
Peeled a section off and can see wet spots in the scratch (big surprise). The stucco peeled off clean, no residue, like it was not bonded at all.
Roof leaks are the first suspition, but I have doubts. If the block was not 100% dry, is it possible for the trapped moisture to be popping the stucco now? Any ideas how to determine the cause? I wish I knew how to post pictures, might help.
Any input would be apprieciated, stucco’s really not my thing, but maybe it will be after this mess. Always seem to learn more when things go south.
Replies
Two things that make stucco blister
(1) Layer of plaster troweled on a sun heated dry or dirty surface.
(2) Finish coat is seal with latex paint, not colored stucco.
He said the entire system is dryvit.
Any thoughts on It?
Dave
Stucco was applied in a tarped and heated space. (northern location)
Finish was coloured stucco, pre-mixed and coloured.
Clean surface(hopefully) new styrofoam.
Again, system was Dryvit (brand name)
Construction is 2x6 frame, 1/2" ply, tyvec, concrete block, 1" styrofoam, scratch, mesh, finish. Entire system is Dryvit.
stucco's really not my thing,
Neither is Dryvit, and you tried to mix and match the two systems without a full understanding of either.
I'm assuming you meant "styrofoam, mesh, scratch." Am I correct?
What is the purpose of the concrete block? Why Tyvec under Styrofoam?
Anyway, you built a disaster because you have a wet sponge, (scratch coat,) between two vapor barriors, (Styrofoam and Dryvit.)
Of course this did allow the scratch coat to cure really well, but now all the excess moisture is being released, but with nowhere to go except in any blisters it creates.
Pull the drywall and drill 1/4" holes on a 6" grid through the plywood, Tyvec, and styrofoam, until the drill hits the scratchcoat, then wait untill the scratch is completely dry before repairing the Dryvit, Great Stuf'ing the holes, and replacing the DW.
SamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
Sam, by scratch and mesh, he may have meant the synthetic stucco base coat used with the fiberglass mesh, rather than the cementious scratch coat of a traditional stucco system.If he clears up the terminology, it should help with the advice.
"Anyway, you built a disaster"
Tell me what you think, Sam. I don't want you to mince words here, be brutally honest. :)
Just to clarify, the "scratch" is as Cloudhidden has said, the thin base coat (also Dryvit) with the fibreglass mesh. The block supports the limestone surrounds and washcourse. The tyvec covers the ply. and there is the typical 1" airspace between that and the block. The foam was applied ontop of the block with the stucco starting there.
Upon further investigation, some of the blisters are dry underneath. What's really odd is we have had numerous failures, on different buildings, finished at different times. Same sub, same project. All showing just this am. We've had rain, but its been raining for weeks on and off, why all the failures just this morning? I'm thinking the relative humidity. The finish coat is peeling off clean, as if it is not bonded to the base.
Can the base, as thin as it is, absorb moisture from the air? If so, has the finish been applied to thin to allow this?
Feel free to give me another blast, your input is invaluable.
Call the mfg or distributor. They need to look at the blisters and see one cut away to analyze what happened. We'd just be guessing. Only time I've had the acrylic base coat delaminate is with a dirty substrate. They'd probably have additional ideas.
Mfg. has been called, its just a bit of a mystery, like to know as much as possible before they get here. There is going to be some significant costs involved, so I don't want to be bamboozled. Actually, it won't be me, I wasn't taking care of the stucco guys. I'm just the guy who gets away with scewin' around on B.T.
Well we're at it, you can't patch stucco can you?
Wayell, since you're not using any stucco at all, I can't blast away anymore.
I'll jest have to save my TNT for sumpin' elase.
. All showing just this am
Did it get really warm or dry in the last 72hrs?
Is there anything common to most spots? Direction, elevation, size, shape?
Well we're at it, you can't patch stucco can you?
Stucco is
easysimple to patch. Drvyvit, I don't know. See: Here.like to know as much as possible before they get here
See: Here
I found a use for some of that dynamite: Quit saying "Stucco!"
Stucco is a cementious product that forms a solid moisture permeable sheathing. Dryvit is a moisture proof acrylic product that creates a weather protective film over foam insulation.
One is structural, the other is paint.SamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
>the other is paint.Whatever else one thinks of it, it's more than paint. There's a color coat that is paint with aggregate, but the base coat is definitely not paint.It's ok to use "stucco" if it's preceded by "synthetic" because that removes the ambiguity. It can be patched, but the patch will probably be visible if only because the original finish coat will have faded some and the patch won't match.
(|;>)SamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
Mornin' Sam
(you be the sheepdog and I'll be Wyle E Carpenter, genius) (Buggs Bunny) (:
O.K. back to business, the failures appear to be random, making it difficult to assess why and how. The weather has been getting warmer, the only significant change has been the humidity. I haven't checked the barrometric pressure, but my thinking is this must be weather related. Either the humidity migrating from the outside, or some trapped moisture migrating from the inside.
And to further confuse things, temp. dropped last night, we got a bit of snow and all the blisters are gone. I'm thinkin' we should pack up the trailer and run away. :)
Consider that it's trapped moisture behind the essentially waterproof synthetic stucco base coat/finish coat barrier. When temps rise, they heat it and it expands. When temps cool, the reverse. The question is, how'd the moisture get there? One possibility is vapor drive. Imagine a winter where the humidity levels inside were higher than those outside. The system will attempt to balance and water vapor can be pulled through the walls where it's trapped by the base coat, which is a de facto vapor barrier.This usually doesn't happen if interior humidity levels are controlled, or if there's a fresh air handling system (active, passive, whatever) that provides a path of less resistance for moisture levels to equalize. But sans that, a tight house with no means for addressing moisture differentials can be prone to this.Not saying your house is experiencing vapor drive, but it's one explanation that fits the evidence. Blisters that appear with heat and disappear with cold indicate trapped moisture. It probably got there from inside or from breaching the exterior (a flaw in the caulking, for example). And if there's moisture there, then one begins to wonder about the health of the framing.
I've been considering vapour drive from the start, but we have both passive and mechanical air exchange systems. The passive in the mech. rms. to supply combustion air and mech. hrv's to supply fresh air. I suspect some residual moisture in the block that has for some reason (envirormental?) decided to blow out now. I also suspect the application because the finish has come off so cleanly. The manufactuerer is due today at 1pm. It will be interesting.
>The manufactuerer is due today at 1pm.I'll be watching for the diagnosis at 2 pm then. :) Best of luck. I look forward to the mfg's explanation.
I think you got it. The finish froze according to the manufacturer. posted the story to Sam,don't call it stucco, T
Thanks for comin' along
The story has a beginning, middle, and end, all in less than 24 hours. Cool.
Very
Just another wacky day here at "The big site"
Glad we could wrap it up in time for the holiday, Have a good one, see ya monday.
Below freezing weather a possibility in creating the blisters? Just hypothesizing here. Also if you had heaters in the tarped areas is it possible that the heater was pointed at the areas that blistered? Dry out the first coat to fast ? Leave a redisue?
Edited 4/4/2007 8:21 pm by dovetail97128
There dosen't seem to be any relation between the location of failures and any obvious cause. ie roof leak, heater location, condensation, etc. The thinking now is that there was some problem with the application. The finish coat did not bond with the base. The real question is why everything failed on the same day. Still a mystery.
> The finish coat did not bond with the base.???Only time I've seen that is when there was a regular source of moisture that kept an area wet and the acrylic kind of disintegrated. Could the finish have frozen?
Freezing is a possibility, any time you tarp and heat, its possible. The finish did not deteiriate, it peeled off in sheets. (o.k. small sheets, but you get the idea) The base was completely clean, a clean seperation between the two.
The expansion and contraction of the blisters id definately weather related. But...
The actual moisture driving them may not be due to recent weather. It could be from a rain or heavy dew any time during the time the styrofoam was on site or earlier and the time it was covered with the dryvit. If you are using coffee cup type styro foam, be aware that it is not moisture impermeable.
You may want to assemble a weather history of the foam from date of manufacture to instalation.
be waiting 2 o'clock.SamT
There are three kinds of people: Predaters, Prey, and Paladins. For the life of me, I can't see why Prey feels safer from predators by disarming and emasculating Paladins.
Manufacturer will test control samples,,,, but he is of the opinion that the finish coat froze before curing. As evident in the way the finish came off so cleanly from the base coat.
Manufacturer will supply the material, sub will patch, client will be approached for funds to cover labour because he insisted on winter progress. Glad I don't handle that part of it.
Its been a bit of a ride, thanks for comin' along.
ave a nice day.
>>What's really odd is we have had numerous failures, on different buildings, finished at different times. Same sub, same project.Go to the Dryvit site and download the full installation instructions.Call the applicator and test him.Betcha he doesn't pass."Installation instructions? I don't need no tinkin' installation instructions. This is the way we always do it."
With my mouth I will give great thanks to the Lord; I will praise Him in the midst of the throng. For He stands at the right hand of the needy, to save them from those who would condemn them to death.
- Psalms 109:30-31
we did
he didn't
We apply Synergy and Adex, Ottawa area.
Possibly a lack of temporary heat. 5 deg C is the minimum.Base coat froze before curing. It was very cold 6 weeks ago. Are the locations lower to the ground, and the higher areas OK? Heat rises.
Possibly not enough rasping to roughen and open up the foamboard to receive the base coat.
Possibly atmosphere contaminated by salamanders burning all the oxygen out of the air.
Improper batching of basecoat. ie not enough resin, or adding water after batching.
It's been about 5 years since I've seen that done, so I've forgotten some of the details, but you brought back memories and gave a very solid list. Frozen base, not enough rasping, improper mixing of base, adding water...all are legit possibilities for causing the problem. Good list.
"improper batching of basecoat"
If this was the case, would we see the failures in just a few spots? Or are we seeing just the tip of the iceberg?