The most recent blogs at Green Building Advisor

Calculating the Minimum Thickness of Rigid Foam Sheathing

Posted on October 15, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

UPDATED on August 26, 2014 with new information on flash-and-batt requirements in the 2012 IRCInternational Residential Code. The one- and two-family dwelling model building code copyrighted by the International Code Council. The IRC is meant to be a stand-alone code compatible with the three national building codes—the Building Officials and Code Administrators (BOCA) National code, the Southern Building Code Congress International (SBCCI) code and the International Conference of Building Officials (ICBO) code.

If you plan to install exterior rigid foam on the walls of your house, how thick should the foam be? Although the GBAGreenBuildingAdvisor.com Web site has addressed this question several times in our Q&A column and various blogs, the question continues to perplex readers. New questions along these lines come our way regularly.

The last time I answered the question was at the end of a long, very technical blog. In this blog, I'll cut to the chase.

Green Building Priority #6 – Ensure Durability and Reuse Existing Buildings

Posted on October 13, 2010 by Alex Wilson in Energy Solutions

A green home should last a long time. Living in a timber-frame home in Dummerston, Vermont that was built in 1785 and having grown up in a log home in Berwyn, Pennsylvania that was built in 1710 (three centuries ago this year), I think a lot about durability. It shocks me to realize that some of the homes being built today are designed for just a fifty-year lifespan. I feel that homes should last a minimum of 500 years.

Should Batt Insulation Be Outlawed?

Posted on October 11, 2010 by Carl Seville, GBA Advisor in Green Building Curmudgeon

A significant amount of my work these days is certifying homes under one or more of the available green building programs in my area, including EarthCraft House, LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. , and the National Green Building StandardNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. . Recently, I have inspected several homes that were insulated with fiberglass batts, and, not surprisingly, the quality of the installation was dismal. What I saw could have been an instruction manual on how not to insulate a house. Batts were cut 2 to 3 inches wider than the stud spacing and crammed into the cavities.

My 8th Commandment: Never Let the Client...

Posted on October 11, 2010 by Michael Strong, LEED Associate, CGP in Business Advisor

There is no greater peril to a green builder/remodeler (or any builder/remodeler, for that matter) than a client who insists on having you do something outside your comfort zone. Clients ask us to do some crazy and some not-so-crazy things for any number of reasons, but trust me: As often as not, these requests are trains at the end of the tunnel, not light!

The History of Superinsulated Houses in North America

Posted on October 10, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Several GBA readers have requested a copy of a presentation on “The History of Superinsulated Houses in North America” that I gave at the 14th Annual Westford Symposium on Building Science (August 3, 2010). I also gave the presentation at the annual meeting of the British Columbia Building Envelope Council in Vancouver (September 22, 2010).

Here it is:
The History of Superinsulated Houses in North America

For more on the topic, check out two blogs with overlapping content:

Basement-to-Living-Space Moisture Problems

Posted on October 8, 2010 by Scott Gibson in Q&A Spotlight

Scott Razzino has an all-too-familiar problem. The basement of his 1,100-sq.-ft. home in Atlanta is chronically damp. He's installed a 65-pint dehumidifier, which must be emptied every day. Surely, he wonders in this Q&A post, there must be a better way to tackle the problem.

Solar Versus Superinsulation: A 30-Year-Old Debate

Posted on October 8, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

The oil price shock of 1973 sparked a burst of interest in “solar houses.” During the 1970s, owner-builders all over the U.S. erected homes with extensive south-facing glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill. — sometimes sloped, sometimes vertical. Many of these houses included added thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. — concrete floors, concrete-block walls, or 55-gallon drums filled with water.

Green Building Priority #7 – Protect and Restore the Site

Posted on October 6, 2010 by Alex Wilson in Energy Solutions

Of all the environmental problems we're causing as a species — including air pollution, water pollution, soil erosion, ozone depletion, and climate change — loss of biodiversity is the most permanent. Ecologists point out that it can take hundreds of thousands or even millions of years of evolution to fill ecological niches that are being vacated by the extinctions we are causing.

Home Builder Tips for Increasing Web Site Traffic

Posted on October 6, 2010 by Dina Lima in Business Advisor

In her book Loyalty is Love, internationally acclaimed speaker and business trainer Beverly Koehn explains that home builders are in the retail business and should ensure that every single contact with home buyers, from the very first interaction, is memorable.

With consumers being increasingly active on social networks such as Twitter and Facebook, home builders should pay attention to the first contact and “user experience” that potential home buyers will have with their company. In this era, that first contact is usually online.

Should Insulated Concrete Forms be Air-Sealed?

Posted on October 4, 2010 by Scott Gibson in Q&A Spotlight

Roger Lin is planning to use insulated concrete forms in a house he hopes will meet 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. standard of 0.6 air changes per hour at 50 Pascals (ACH50). ICFs are rigid foam building blocks stacked like Legos and then filled with concrete.

Lin has been told by ICF manufacturers they won't need air-sealing, but he's not so sure.

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!