The most recent blogs at Green Building Advisor

Earth Day 2014 and Climate Change

Posted on April 24, 2014 by Alex Wilson in Energy Solutions

With Earth Day having been this week, I’ve been musing about the state of our environment and where we’re heading.

Does Open-Cell Spray Foam Really Rot Roofs?

Posted on April 23, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Murmurs and hearsay about open-cell spray foam insulation have been gaining traction for a while. It rots roofs, people have told me. Not long ago, someone even told me that in Florida, roofing companies won't let their workers go up on roofs with open-cell spray foam because the roofs are so spongy, the guys fall right through.

Open-cell spray foam is getting a bad reputation among some people in the construction industry. But is it deserved?

My Earth Tube Story

Posted on April 22, 2014 by Malcolm Isaacs in Guest Blogs

I saw my first “earth tube” back in 2004, on a tour of row houses in Darmstadt, Germany — a tour which had been organized by the PassivhausA 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. Institut (PHI) to show international visitors some examples of Passivhaus construction. As a visiting Canadian engineer specializing in residential energy efficiency, this was a novel and, for me, unheard-of way to temper incoming ventilation air from extremes of heat and cold.

Building a Foolproof Low-Slope Roof

Posted on April 21, 2014 by Scott Gibson in Q&A Spotlight

Carolyn Wood is building a house 80 miles north of Vancouver, British Columbia, and if nothing else she'd like to get all the details in the roof assembly right. The question is whether the house is too far along to let her reach that goal.

The roof, with a 2-in-12 pitch, is framed with I-joists, strapped with 2x4s, and sheathed with 1/2-in. plywood. Above the roof sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. , the roofers plan to install NovaSeal roofing underlayment and standing-seam metal roofing.

All About Radiant Floors

Posted on April 18, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

So-called radiant floors have an excellent reputation. Many customers report that this type of heating system is comfortable and quiet. Moreover, some suppliers of radiant floor materials and equipment claim that these systems can save energy.

In spite of the purported benefits of this type of heating system, few green homes include a radiant floor heating system. This article will explore why.

How Much Water Does it Take to Turn on a Light Bulb?

Posted on April 17, 2014 by Alex Wilson in Energy Solutions

In last week's blog I took a look at some of the water conservation features in our new house, but I began the blog by addressing the relationship between water and energy. That got me curious, so I’ve been digging deeper into this water-energy nexus, examining the water-intensity of our different electricity sources.

How to Detect an Internet Solar Energy Scam

Posted on April 16, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

All I was trying to do was find some sports scores on Yahoo the other day when I saw it. I don't go looking for this stuff, and when I do see it, I try to ignore it. But this one clotheslined me with an unfair term.

That's the ad in question to the right. Have you seen it? I probably shouldn't tell you the name of the website (powerfreedom.com), but the kryptonite term that made my fingers go apoplectic was “free energy.” Seeing it capitalized intensified the effect. And the photo! Is that a diseased wireless router robot surrendering its secrets to me?

Germany’s Bioenergy Villages

Posted on April 15, 2014 by Andrew Dey in Guest Blogs

The notion that a village can produce as much energy as it consumes is not new in Germany, nor is it exclusive to this country that has set aggressive targets for renewable energy use. In the mid-1990s, for example, the Austrian village of Güssing began implementing strategies to use local biomassOrganic waste that can be converted to usable forms of energy such as heat or electricity, or crops grown specifically for that purpose. to produce electricity and heat, and the Danish island community of Samsø installed wind turbines to meet its electrical needs.

Can’t Anyone Get Things Right?

Posted on April 14, 2014 by Carl Seville, GBA Advisor in Green Building Curmudgeon

In my business of certifying buildings, most of my work involves working with architects, contractors, and trade contractors who are trying to create green buildings. Unfortunately, they frequently miss the mark in some key areas.

Many of them are well intended but don’t have a broad enough view of their projects. Others only do the minimum required to meet a green building standard forced on them by someone else. And a few, thankfully, seem to get it and work hard to do the right things.

This post, the first in a series about problems I run across, will focus on HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building..

Thermal Barriers and Ignition Barriers for Spray Foam

Posted on April 11, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Do building codes require spray foam insulation to be protected with a layer of drywall or a comparable barrier for fire safety? The answer is yes, usually — but not always.

There is no simple answer to the question, for several reasons. The first reason is that the code is complicated.

The second reason is that the code is poorly written.

The third reason is that the code is subject to interpretation by local code officials.

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