Thursday, July 20, 2017

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

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There is mold on the factory-primed, latex top-coated wood clapboards on the south but not the north side of our house
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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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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/pete-s-puzzle-mold-painted-clapboards-food-thought

Wednesday, July 12, 2017

62 Things We Should Ban to Improve Home Building

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Let’s clean this mess up once and for all
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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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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/62-things-we-should-ban-improve-home-building

Wednesday, June 28, 2017

Air Sealing the Ceiling Joists in an Attached Garage

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A little forethought makes it a lot easier
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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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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/air-sealing-ceiling-joists-attached-garage

Thursday, June 22, 2017

Combining Sheathing With a WRB and Air Barrier

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How well do Zip and ForceField sheathing integrate a structural panel with bulk water and air management?
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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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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/combining-sheathing-wrb-and-air-barrier

Wednesday, June 14, 2017

Climate Change Is Just a Theory

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And it was started by a Frenchman in 1827
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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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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/climate-change-just-theory

Wednesday, June 7, 2017

Is Compressed Fiberglass Insulation Really a Problem?

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Or is this just another myth in the world of building science?
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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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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/compressed-fiberglass-insulation-really-problem

Wednesday, May 24, 2017

Heating Degree Days Drop Again in 2017

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It’s not happening everywhere, but Atlanta, Aspen, and other places saw the downward trend of HDD continue
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We've had some beautiful cool weather here in Atlanta this spring. It's about 50°F outdoors as I write this, one week into the month of May. The high yesterday was only about 70°F.

We're getting a few more heating degree days (HDDThe difference between the 24-hour average (daily) temperature and the base temperature for one year for each day that the average is below the base temperature. For heating degree days, the base is usually 65 degrees Fahrenheit. For example, if the average temperature for December 1, 2001 was 30 degrees Fahrenheit, then the number of heating degrees for that day was 35.) in the middle of May. (Heating degree days are really just another way at looking at temperature, which I explained in more detail in a look at the fundamentals of degree days.) We occasionally pick up some HDD even in July and August. But it's the winter HDD that matter for heating — and that give us a clue about the climate.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/heating-degree-days-drop-again-2017