Failed house in Belgium--vapor drive from exterior?

[ThingOfBeauty]

Martin put up an interesting article about a building failure on his GBA blog.

One of the interesting statements is down in the comments--as usual they are excellent.
"...there really aren't any diffusion-related disasters due to diffusion of interior moisture outward. On the other hand, there are an increasing number of diffusion-related disasters due to diffusion of exterior moisture inward."

That squares with my experience. Of all two diffusion-related problems I've ever seen, both were vinyl wallpaper on the inside of a masonry wall.

What are you guys seeing out there?

[David Meiland]

Re: Failed house in Belgium--vapor drive from exterior?

Aren't extreme cold climates subject to problems with outward diffusion, and/or at least problems with interior air leakage into wall cavities?

[Dick Seibert]

Re: Failed house in Belgium--vapor drive from exterior?

What are you guys seeing out there?

I'm seeing tons or money being made by contractors smart enough to testify against the idiots who seal up walls and use products like ground up newspapers, sealants, and Flakeboard. Over the last 12 years I've posted pictures of:

1) People moved out of their homes because of sealants around windows emiting formaldehyde and Stoddard solvents.

2) An apartment where the people were moved out because of mold growing in styrofoam sprayed around windows.

3) People moved out of their homes because of ground up newspaper used as insulation emitting formaldehyde.

4) Reports of people getting sick in homes clad in OSB.

5) I've told many times of the reports I did on our sealed-up apartments in the 80s, even flying up and showing a picture of failed buildings in Vancouver's sealed-up condo crises, now going on for 4 decades and costing billions.

6) Recently I showed pictures of mold growing out of California's new formaldehyde-free plywood subfloor on the home I'm building. In the future there will be no more plywood on walls for me, walls have to breathe (Which means air-in/air-out, permeability doesn't do it), and at one of our Building Standards Commission hearings DuPont argued WRBs have to have a minimum perm rating of 50, Dow trying to push their styrofoam argued against DuPont that 4 or 5 was adequate since asphalt felt had performed admirably for a century, yet those walls didn't have insulation in them.

I can't comment on the earth tubes never having seen them, but on HVAC ducting I actually drill holes in low spots to insure against water build up, mold, and legionnaires disease, and to save a dollar many criminals are going around sealing them up.

Go ahead, keep sealing them up guys, so we can make money by suing you, frankly I think any building with OSB, styrofoam, ground newspaper, or toxic sealants should be torn down. Oddly enough, Riversong of all people had the right idea, go back to sheathing with boards, for his insulation go to the printing facility, take the end cut-offs without ink and grind them up in your office shredder. I don't know anything about the Belgian legal system as to whether they can sue this Wolfgang guy for his bad methods, but I sure hope they can sue him out of existence.

Green is toxic!

[Dancing Dan]

Re: Failed house in Belgium--vapor drive from exterior?

That was an interesting piece. And as a cold-climate builder it's one of those issues that keeps me awake at night. I'm always looking for these "cold sheathing" failures I keep hearing about, but have yet to have anyone tell me they've experienced it in a way that wasn't related to some other problem, mostly bad insulation installation.

[Ted S.]

Re: Failed house in Belgium--vapor drive from exterior?

Martin put up an interesting article about a building failure on his GBA blog.

One of the interesting statements is down in the comments--as usual they are excellent.
"...there really aren't any diffusion-related disasters due to diffusion of interior moisture outward. On the other hand, there are an increasing number of diffusion-related disasters due to diffusion of exterior moisture inward."

That squares with my experience. Of all two diffusion-related problems I've ever seen, both were vinyl wallpaper on the inside of a masonry wall.

What are you guys seeing out there?

I never saw one either. I always thought the vapor barrier was more of a problem then it's omission. If vapor diffusion is considered in envelope design it should be for drying.

[Dick Seibert]

Re: Failed house in Belgium--vapor drive from exterior?

Outside the failure, the pictures of those houses are sure fugly, they look like gas chambers. Larry Ellison was recently giving a talk about his remembrances of Steve Jobs, Jobs was showing him pictures of his proposed Apple stores, Ellison stated: "Brick and Mortar is dead", Jobs responded: "These aren't brick and mortar, they are steel and glass". With all the beautiful steel and glass buildings I see in Europe, why in the world are they still building fugly brick homes?

[Dancing Dan]

Re: Failed house in Belgium--vapor drive from exterior?

I agree, Ted - I have a suspicion that in 5-10 years the conventional wisdom will be multiple air barriers, no vapor barriers. At least in all but the most extreme hot or cold climates.

[David Meiland]

Re: Failed house in Belgium--vapor drive from exterior?

I need to re-read Martin's piece, because I didn't come away with a clear sense of which problem was worse... interior humidity caused by the HRV/earth tubes, or the vapor drive from the exterior. Either way it sounds like the interior OSB was the ultimate problem.

[ThingOfBeauty]

Re: Failed house in Belgium--vapor drive from exterior?

I need to re-read Martin's piece, because I didn't come away with a clear sense of which problem was worse... interior humidity caused by the HRV/earth tubes, or the vapor drive from the exterior. Either way it sounds like the interior OSB was the ultimate problem.

I agree, the article doesn't seem to come down firmly on which was "the" problem.
Since human health impacts were the result of the problem(s), and they vary significantly (i.e. what affects one person may not affect the next, and vice versa), I think the exact primary cause is not known.
It does sound like the interior OSB may have been one locus of the biological growth problem (with the ventilation air system being the other locus).
Anyway that's what I took out of the article.

[Martin Holladay]

Re: Failed house in Belgium--vapor drive from exterior?

I agree that this house had at least two major problems, and it's hard to separate which problem was the worst.

Dancing Dan -- I think that no one is going to see "cold sheathing" failures as long as the sheathing can dry seasonally to the exterior. A rainscreen gap goes a long way towards assuring that happens quickly.

Interior moisture can contribute to wall failures -- but the transport mechanism is almost always air leakage (exfiltration), not diffusion.

And Dick Seibert: if you are going to testify as an expert witness in court, you should learn more about building materials. It isn't possible to find "mold growing in styrofoam sprayed around windows," because Styrofoam isn't sprayed around windows. Styrofoam is a brand of rigid foam manufactured by Dow, and it isn't used to stuff the gap around a window.

[Ted S.]

Re: Failed house in Belgium--vapor drive from exterior?

I have a suspicion that in 5-10 years the conventional wisdom will be multiple air barriers, no vapor barriers.

A lot of folks knock Energy Star for being too easy (at least before the new Version 3.0) but they have promoted the interior and exterior air barrier on above grade walls for many years.

[Dick Seibert]

Re: Failed house in Belgium--vapor drive from exterior?

And Dick Seibert: if you are going to testify as an expert witness in court, you should learn more about building materials. It isn't possible to find "mold growing in styrofoam sprayed around windows," because Styrofoam isn't sprayed around windows. Styrofoam is a brand of rigid foam manufactured by Dow, and it isn't used to stuff the gap around a window.

Go ahead and nitpick, but Styrofoam has become the generic named for all this junk, junk that we are banning city by city and now there is a bill in the legislature to ban it statewide, be it food plates, packing peanuts, or insulation.

In the United States and Canada, the word styrofoam is often incorrectly used as a generic term for expanded (not extruded) polystyrene foam, such as disposable coffee cups, coolers, or cushioning material in packaging, which are typically white and are made of expanded polystyrene beads. This is a different material from the extruded polystyrene used for Styrofoam insulation. The polystyrene foam used for craft applications, which can be identified by its roughness and by the fact that it "crunches" when cut, is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint, and is not specifically identified as expanded or extruded. Another tradename for expanded polystyrene is thermacol, originated by BASF.¹

If you are going to keep pushing this obsessive/compulsive hysteria perhaps you should take this webinar.

[Martin Holladay]

Re: Failed house in Belgium--vapor drive from exterior?

Wikipedia is correct: used informally, "styrofoam" refers to EPS -- not spray foam used to seal the gap between window frames and window rough openings.

[Martin Holladay]

Re: Failed house in Belgium--vapor drive from exterior?

Dick,
The link you provided is for a Webinar about "emerging risk in green design and construction."

You're preaching to the choir, Dick. Of course green construction techniques come with increased risks for the builder -- after all, the article I wrote about the failure in Belgium is on that very topic. I've been reporting on these risks and failure stories for years, so that builders and designers can learn about risks and improve the way they build.

[NW Architect]

Re: Failed house in Belgium--vapor drive from exterior?

Interesting article and interesting responses. NOBODY, however, has suggested rainwater leakage through the brick. Since there is no WRB in the assembly, water penetrating the brick will be able to traverse the gap at every anchor and at every mortar dropping. Without a WRB, that liquid water will be readily absorbed by the sheathing. The sheathing is wet long before any vapor drive occurs