Green Building

Pete’s Product Puzzle: VersaDry

Subtitle:  Simple folded metal solves a common moisture problem Images: 

I first “learned” about VersaDry when a colleague of mine here at BuildingGreen — our materials and product expert, Brent Ehrlich — sent me the photo reproduced at right. I was in the same boat you are right now: “OK, thanks for the photo, Brent, but what the hell is this VersaDry bent-metal thingamajig?”

He replied, “Oh, yeah, here is another photo that will help.” This time he sent me the photo reproduced as Image #2, below.

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Thinking Clearly About the 3 Levels of the Building Enclosure

Prime:  prime Subtitle:  Doing so can help you avoid scams, investigate failures, and maximize performance Images: 

When you approach the subject of building science, especially regarding heat, air, and moisture flows through a building enclosure, it's easy to get confused. There's a lot to learn: blower door testing, insulation grading, R-value, vapor permeance, radiant barriers, combustion safety, solar heat gain coefficients, and on and on. That's why we break things down into simpler pieces.

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Is It Possible to Get Condensation on a Sponge?

Prime:  prime Subtitle:  A little building science puzzler on moisture and the properties of materials Images: 

I recently taught a class called What the Duct!? at the Builders' Boot Camp in Virginia. Paul Francisco was one of the other instructors (teaching about indoor air quality), and on the last evening at dinner, our conversation turned to building science. (Imagine that!)

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An Interesting Moisture Problem in a Trendy Restaurant

Prime:  prime Subtitle:  Observations by astute diners give clues as to the source Images: 

I've got the curse, you know. I can't walk into a building and not check out what's going on with ductwork, windows, and anything else that lets me apply what I know about building science.

Recently, I went to lunch at a trendy restaurant near Emory University and of course looked up at the ceiling. You can see what caught my attention in photo at right. The restaurant is only three or four years old, so I've been watching this problem get worse for a while now.

I have a few ideas about what's happening here. Do you?

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SonicLQ: Reconnecting Acoustics and Airtightness

Subtitle:  Early on in our work on energy-efficient homes, the connection between airtightness and sound centered on airport noise; now a new technology reconnects acoustics and air leakage Images: 

Back in the early days of airport noise mitigation programs, there was a pretty strong link between air leakage and sound. A document titled “Tips for Insulating Your Home Against Aircraft Noise” noted, “Sound travels from the exterior to the interior of the home in two ways: through solid structural elements and through the air…. Wherever air can infiltrate a home, sound can as well.”

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The Truth About Al Gore’s Carbon Footprint

Prime:  prime Subtitle:  Now that Gore’s new movie is showing in theaters, the attacks on his credibility have begun Images: 

Al Gore is in the news again. His new climate change movie, An Inconvenient Sequel: Truth to Power, is in theaters now. And that means the folks who don't believe in climate change — or at least folks who don't believe that humans have any impact on it — are out in force trying to discredit the message.

As was the case 10 years ago when Gore’s original movie came out, they're going after his carbon footprintAmount of carbon dioxide and other greenhouse gases that a person, community, industry, or other entity contributes to the atmosphere through energy use, transportation, and other means. and making the case that he's a hypocrite. Let's take a look at the issues.

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The Joy of Flex

Prime:  prime Subtitle:  A recap of my Building Science Summer Camp presentation Images: 

I recently spoke at the Westford Symposium on Building Science. You may know it better as Building Science Summer Camp, since that's what everyone calls it. I'll fill you in on what you missed if you weren't there.

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Raised-Heel Trusses Make Better Enclosures

Prime:  prime Subtitle:  This is another easy advanced framing technique for every home with roof trusses Images: 

A comfortable, energy-efficient home begins with a good building enclosure. That means control layers. You've got to control the flows of moisture, air, and heat.

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Using Total Effective Length in Duct Design

Prime:  prime Subtitle:  For air flow purposes, a duct system is often much longer than it appears Images: 

Today I’m going to explain an important concept in one of the most popular ways of doing duct design. I’ve been writing a series on duct design over at my blog and began with a look at the basic physics of air moving through ducts. The short version is that friction and turbulence in ducts results in pressure drops. Then in part 2 I covered available static pressure. The blower gives us a pressure rise.

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Pete’s Puzzle: Mold on Painted Clapboards is Food for Thought

Subtitle:  There is mold on the factory-primed, latex top-coated wood clapboards on the south but not the north side of our house Images: 

Whenever my wife starts a conversation with, “OK, Mr. Building Scientist,” I know I am in some kind of trouble. That proved to be the case one day when we were out hanging laundry on the south side of our house.

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62 Things We Should Ban to Improve Home Building

Prime:  prime Subtitle:  Let’s clean this mess up once and for all Images: 

Let's face it. The state of home building isn't good. Yes, we have building science and energy codes and green building programs out the wazoo. We have cool new products and home energy raters and even Joe Lstiburek. Despite all this, we still have wild ductopuses, holey air barriers, and insipid insulation installations.

And I've finally lost my patience. I think the only way to improve the state of home building in America is to ban these things.

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Air Sealing the Ceiling Joists in an Attached Garage

Prime:  prime Subtitle:  A little forethought makes it a lot easier Images: 

The I-joists in the lead photo here run across the top of the wall between the dining room and the attached garage in this home under construction in the Atlanta area. In the old days, before anyone worried about air moving through those joist cavities, the builder didn’t bother to do anything beyond securing the joists.

You can see here, though, that the builder of this home knows a thing or two about air sealing because they've put blocking between the joists. But what do they do next?

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Combining Sheathing With a WRB and Air Barrier

Subtitle:  How well do Zip and ForceField sheathing integrate a structural panel with bulk water and air management? Images: 

Full Disclosure: First, there are a lot of different ways to get continuous air and water control layers on the exterior of a building enclosure. You can use housewrap, taped-and-sealed rigid foam insulation, liquid-applied membrane, or either the Huber Zip or Georgia-Pacific ForceField system. Each approach has strengths and weaknesses.

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Climate Change Is Just a Theory

Prime:  prime Subtitle:  And it was started by a Frenchman in 1827 Images: 

So the United States has announced it's withdrawing from the Paris Accord, the international agreement with nonbinding measures to mitigate the effects of climate change. Now everyone's up in arms, speaking in exasperated tones about the travesty of this decision.

"But... but... the science," they say. Yeah, let's talk about science.

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Is Compressed Fiberglass Insulation Really a Problem?

Prime:  prime Subtitle:  Or is this just another myth in the world of building science? Images: 

I've been guilty of perpetuating a myth. Not long ago I wrote an article in which I said installing insulation, "cavities [should be] filled completely with as little compression as possible." But is compression really such a bad thing? Here on GBAGreenBuildingAdvisor.com, commenter Dana Dorsett wrote, "Compression of batts is fine (resulting in a higher R/inch due to the higher density) as long as the cavity is completely filled.”

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