Building Science

Thinking Clearly About the 3 Levels of the Building Enclosure

Posted on September 20, 2017 by Allison A. Bailes III, PhD

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.

Is It Possible to Get Condensation on a Sponge?

Posted on September 13, 2017 by Allison A. Bailes III, PhD

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!)

An Interesting Moisture Problem in a Trendy Restaurant

Posted on September 6, 2017 by Allison A. Bailes III, PhD

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?

SonicLQ: Reconnecting Acoustics and Airtightness

Posted on August 24, 2017 by Peter Yost

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.”

The Truth About Al Gore’s Carbon Footprint

Posted on August 23, 2017 by Allison A. Bailes III, PhD

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.

The Joy of Flex

Posted on August 16, 2017 by Allison A. Bailes III, PhD

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.

Raised-Heel Trusses Make Better Enclosures

Posted on August 9, 2017 by Allison A. Bailes III, PhD

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.

Using Total Effective Length in Duct Design

Posted on July 26, 2017 by Allison A. Bailes III, PhD

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.

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

Posted on July 20, 2017 by Peter Yost

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.

62 Things We Should Ban to Improve Home Building

Posted on July 12, 2017 by Allison A. Bailes III, PhD

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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