NAHB Green Building Guidelines

The other day I listened to a conventional builder talk about spray foam and sealing duct work and installing CFLs. I asked him if he realized that he was an “accidental green builder?” His response was that he felt he had to build to a high standard or else he would lose his custom home clients. Green building is just another word for good, solid, accountable construction processes and strategies.

The new NAHB guidelines will be officially released at the International Builder’s Show in Orlando in February but you don’t have to wait until then to see them in a preliminary setting. In short they are a great start into the green building process but they lack standard performance testing - the cornerstone of accountability.

The NAHB has a new website called www.nahbgreen.org. You can register for free and use their scoring tool to see how green your proposed building is. It is a very slick interface worth trying.

The preliminary NAHB guidelines which will be finalized at the International Builder’s Show in Orlando in February, contain 67 areas that are divided into 6 categories:

The biggest category is Resource Efficiency . There are 12 areas to address, let’s take an in-depth look at 3 of those.

Floor Plan   9 points possible:

For example if you can fit 3-bedroom in a 1825 square feet home you get 1 point. If you can fit those rooms in a 1619 sq ft home, you get 4 points. If by clever use of space you can fit 3-bedroom in 1277 sq ft, then you get the maximum of 9 points. A chart of points relates square footage to number of bedrooms.

Building Material Optimization   21 points possible:

 Finish-ready materials are worth 4 points; pre-cut (joist) or pre-manufactured (truss) floor is worth 3; pre-cut (joist) or pre-manufactured (truss) roof framing package is worth another 3; Use a panelized wall framing system and get 6 points; Incorporate a a panelized roof system for 6 more points. Modular construction of the entire house earns 7 points.

Water Diversion   26 points possible:

Earn 7points by installing a perimeter drain for all basement footings sloped to discharge to daylight, dry well, or sump pit. Get 6 points by installing a drip edge at eave and gable roof edges. Get 6 more points from  putting in a gutter and downspout system to divert water 5 feet away from foundation and from there into the overall onsite drainage area. 7 more points if you divert surface water from all sides of building. Slope top of backfill to achieve settled slope of at least 6” of fall within 10 feet of the foundation walls

Green building is a matter of products, process, and design. Just tweaking your existing methods can often get you in the door of a whole new field. The 67 areas are a way of organizing what you are already doing; think of it like a map that organizes the green potential of a home.

There is no penalty based on the size of the home so large custom homes can be certified as green under the NAHB guidelines. The NAHB guidelines does NOT require a blower door test or a duct blaster test, although you will receive points for testing. We at GWS feel that measuring with instruments is a vital component of the whole-house systems approach and believe those points are critical in the ultimate performance of the home. It is more than just points - the house HAS TO PERFORM. Without testing, you cannot assure performance.

Every single builder in America believes in their heart of hearts that they build an energy efficient home; but we know this may not be reality. Just last week a GWS inspector had to fail a home insulated with spray foam because it didn’t meet the blower door test for a tight home. The product was good but the process by which it was applied was inferior. Unfortunately, you simply cannot determine energy efficiency with a visual inspection only, measurement instruments are required. Our industry has to have accountability for the building process. Good enough is no longer good enough. We have to move our industry into superior, high-performance building. “We” means you and I together. GWS is a trusted partner.

We would like to see builders follow the NAHB green building guidelines AND have each home Energy Star certified which includes the blower door test and duct blaster test.

For more information, please contact GWS @ 1-888-488-0206 or visit our web site www.gwssi.com.

 

Wider and Deeper
“The GWS newsletter is designed to provide a broader perspective. We want to be thought of first as a building science resource, second as a holistic advisor. We advise builders how to construct more energy efficient structures. We certify buildings as LEED, Energy Star, Health House, and various regional green programs. But beyond that, our goal is to keep those basic resources in front of you and then deliver above and beyond what you might expect.

Go wider: absorb global issues, become a Renaissance builder who builds better homes and better worlds. Read some architecture, urban planning, green business, scientific studies on carbon, innovations, lessons learned, best practices and profitable building strategies.

Go Deeper: Catch the headlines, then delve into the source. Dialogue with us then we all learn more.”

We at GWS are leaders in the industry; the defining characteristic of good leadership is a good followership. Partner with us as we face the challenges, local and global, of this century. Again, dialogue with us. Tell us your thoughts at newsletter@gwssi.com.

Your Problems are Our Business,

Sincerely,
Kelly Parker, P.E.

This newsletter has been brought to you by GWS, Energy Star Partner of theYear for 2006