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

Thursday, May 18, 2017

Installing Basement Waterproofing from the ‘Negative’ Side

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Of course the best way to waterproof any below-grade assembly is from the exterior — but what if you have to work from the interior?
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Negative-side waterproofing (NSW) is a tough topic that I have frankly been dancing around for quite some time. Manufacturer claims and homeowner anecdotes of successful interior waterproof solutions for basement walls and slabs did not completely add up. But I did not think that I understood the topic or the physics well enough to challenge the claims or explain my skepticism.

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from Building Science http://www.greenbuildingadvisor.com/blogs/dept/building-science/installing-basement-waterproofing-negative-side

Wednesday, May 17, 2017

Three Easy and Essential Advanced Framing Techniques

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Stick-built homes that don’t use these techniques are missing an easy opportunity to save energy and cut construction costs
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Most new homes in North America are built with sticks. The early home builders used bigger pieces of wood — timbers — and when the smaller dimensional lumber that we use so much today hit the market, they scoffed at those new-fangled little woody things, calling them sticks. Now our home construction industry is full of people who do stick building and the home you live is most likely stick-built. And sadly, many of the techniques used to build many of those homes are the same used before we started insulating them.

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from Building Science http://www.greenbuildingadvisor.com/articles/dept/building-science/three-easy-and-essential-advanced-framing-techniques