The most recent blogs at Green Building Advisor

Urban Rustic: Air Sealing the Attic Floor

Posted on December 5, 2017 by Eric Whetzel in Guest Blogs

Editor's note: This post is one of a series by Eric Whetzel about the design and construction of his house in Palatine, Illinois, a suburb of Chicago. The first blog in his series was called An Introduction to a New Passive House Project; a list of Eric's previous posts appears below. For more details, see Eric's blog, Kimchi & Kraut.

Why Solar Microgrids Are Not a Cure-All for Puerto Rico’s Power Woes

Posted on December 4, 2017 by Anonymous in Guest Blogs


In addition to its many other devastating human consequences, Hurricane Maria left the island of Puerto Rico with its power grid in ruins. Power was knocked out throughout the island, with an estimated 80% of its transmission and distribution wires incapacitated. When hospitals and other critical users could not get backup power and water supplies ran low, an extended outage became a humanitarian crisis that has yet to be resolved.

Lumber from a Bandsaw Mill

Posted on December 1, 2017 by Martin Holladay in Musings of an Energy Nerd

Let’s say that you own a piece of land and you want to build a house. If you live in a forested region, the first step is to cut down enough trees to create the needed open space for your foundation, lawn, and driveway.

As you’re cutting down the trees, you may think to yourself, “I’m going to need to buy lumber to build my house. I wonder if these logs can be milled into 2x6s and 2x10s.” The answer is: they probably can.

Extending the Reach of a Moisture Meter

Posted on November 30, 2017 by Peter Yost in Building Science

Typical pins on moisture meters are ½ inch long, meaning you can only determine moisture content by weight near the surface of building assemblies and materials (including wood, gypsum wallboard, and concrete). But I often find myself needing to assess moisture content of first condensing surfaces in walls and ceilings or well below the surface of basement slabs.

This article looks at ways to extend the reach of a moisture meter. (For introductory information on moisture meters, see Tools of the Trade: Moisture Meters.)

Two Rules for Humidity

Posted on November 29, 2017 by Allison A. Bailes III, PhD in Building Science

Because I've written so much about moisture in buildings, I get a lot of questions on the topic. Some are about walls. Some are about the attic. Some are about windows. Some are about the crawl space (which generates the most questions on this topic).

The key to answering a lot of those questions boils down to an understanding of how water vapor interacts with materials. Once you know that, it's easy to see the two rules for preventing damage from humidity.

Flatrock Passive: Installing Windows and Doors

Posted on November 28, 2017 by David Goodyear in Guest Blogs

Editor's Note: This is one of a series of blogs by David Goodyear describing the construction of his new home in Flatrock, Newfoundland, the first in the province built to the Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. standard. The first installment of the blog series was titled An Introduction to the Flatrock Passive House. For a list of Goodyear's earlier blogs on this site, see the "Related Articles" sidebar below; you'll find his complete blog here.

There’s Mold in My Attic

Posted on November 27, 2017 by Scott Gibson in Q&A Spotlight

A three-season cabin built in the 1940s became a year-round dwelling two years ago, but owner Marty Pfeif has discovered an alarming problem: a bumper crop of mold in the attic.

In a post at the Q&A forum, Pfeif ticks off the particulars, including no apparent attempts at air-sealing, "shake and rake" R-19 insulation on the attic floor and some batting against the walls, no vapor barrier, and a ridge vent but no gable vents.

What’s the Definition of ‘Green Building’?

Posted on November 24, 2017 by Martin Holladay in Musings of an Energy Nerd

Recently I spent some time accumulating definitions of “green building” from as many sources as possible. These various definitions included ten different characteristics of green buildings.

Of course, not all definitions agree, and none of the definitions include all ten of the characteristics that I identified in the various definitions.

The three most common characteristics appeared in most of the definitions. According to most sources, a green building:

  • (1) Is energy-efficient.
  • (2) Is water-conserving.

These Southern Cities Are Going 100 Percent Clean (Energy)

Posted on November 22, 2017 by Robynne Boyd in Guest Blogs

If the South were its own nation, it would be the seventh-largest carbon emitter in the world, according to the Southern Environmental Law Center (SELC). The region has more than 200 coal-fired power plants, and renewable energy policies in southern states are few and far between.

California Needs to Rethink Urban Fire Risk

Posted on November 21, 2017 by Anonymous in Guest Blogs


We recently witnessed the wind-driven Tubbs fire blast its way through densely urbanized neighborhoods in northern California, causing dozens of fatalities and thousands of home losses. This tragic event easily ranks as the most catastrophic fire in modern California history. Stories of how fast the fire spread and how little time people had to evacuate are stunning.

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