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A Custom Builder's First EarthCraft House

In the journery to build green homes, Energy Star is square 1. Now, it was time to jump beyond energy efficient homes and into green building certification.

Posted on Aug 3 2010 by Danny Kelly

Having completed an Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. house, we wanted to take the next step in our “walk, jog, run” model. We were ready to jog – we decided to enroll a house in one of the many programs that certifies green homes.

By this time, our knowledge had grown, and we felt like we were up to speed on all the new products and techniques of green building. The NAHBNational Association of Home Builders, which awards a Model Green Home Certification. had formalized its Green Building Guidelines; we had read them and attended a brief seminar.

Trying to decide which program to follow was a tough decision. We thought the LEED for HomesLeadership 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. program had the best name recognition, but we were put off by the fact that the program required any fireplace to be equipped with glass doors. We knew none of our customers would want this, and we didn’t want to risk doing something in a spec home that could turn someone off.

We decided to build a house that would meet the Earthcraft House certification. We wanted to go the extra mile with this house: we wanted spray foam insulation, a conditioned attic, and closed crawlspace. We were thinking green in a big way!

Sometimes it’s too late to change the specs
We met with our third-party verifier — a great guy who really knew his stuff. While reviewing the Earthcraft checklist, we learned what he would be looking for and how to document what we were doing.

Since we had been building custom homes for a number of years, we were already building a pretty good house — for example, we were paying close attention to flashing details. Once again, we were pretty surprised that we had enough points to qualify for a Tier I Earthcraft House without changing our specifications very much beyond the components we had already decided to include: the spray foam, conditioned attic, and sealed crawl space.

We were even thinking, “We’re not really learning anything new or improving anything if we don’t end up changing the way we are doing things.” We wanted to try to get to Tier II or III and incorporate some new things in the mix. But by then, construction had already started, and we had used a traditional termite spray on the foundation. Under the Earthcraft program, you can’t achieve Tier II or III certification unless you use an alternative method for controlling termites — so were stuck at a Tier I.

Lesson learned: you can’t make it up as you go along! One of the most important aspects of green building is thinking and planning ahead.

Tentative steps toward advanced framing
I think the biggest thing that we had to change was our framing techniques. Before we started down the green path, we took a great deal of pride in the fact that our homes were overengineered — so incorporating advanced framing techniques was hard for us to handle. Since we had to include three advanced framing techniques to get our certification points, we chose items that didn’t make us uncomfortable. We decided to use ladder “T wall” intersections, two-stud corners, and insulated headers.

All of these techniques made sense to us — after all, removing lumber and adding insulation is a good thing. On a large custom home, we did not feel quite as comfortable with single top plates or 24-inch-on-center framing, so we chose not to cross that bridge quite yet.

Our first steps towards advanced framing techniques represented a very small bump on our otherwise smooth journey to green.

Inviting the public to watch
We intended to use our first EarthCraft house as a tool to educate people about green building. By now we had learned that the green building focuses on the process, the details, and the performance of a home — in other words, things that are hidden behind the walls. We wanted to prove that you could build a traditional-looking house and still build it greenProfessional, nonprofit membership organization that promotes healthy, energy- and resource-efficient buildings in California. It was formed in 2005 in a merger of Bay Area Build It Green and The Green Resource Center of Berkeley. Headquartered in Berkeley, Build It Green offers professional training and other support services, maintains a regional green products database, and administers the Green Point Rated home certification program..

We hosted several groups, walking them through the house during construction. To spread the green news, we also entered the house in the North Carolina Sustainability and Solar Home Tour.

A disappointing HERS Index
We passed all our inspections (including the blower door test and the Duct BlasterCalibrated air-flow measurement system developed to test the airtightness of forced-air duct systems. All outlets for the duct system, except for the one attached to the duct blaster, are sealed off and the system is either pressurized or depressurized; the work needed by the fan to maintain a given pressure difference provides a measure of duct leakage. test) on the first try. Unfortunately, when our house was only half-built, our third-party rater decided to leave his company. Since his replacement was not nearly as knowledgeable, the verification process wasn’t as smooth as usual during the home stretch.

However, these glitches weren’t anything that we couldn’t overcome. It also took a very long time to finally receive our certification — over two months. We never found out whether this was the fault of the verifier or the people at SouthFace who run the Earthcraft program. (I suspect it was our verifier.)

Our HERS Index was a 69 — a bit of a disappointment. Since the house incorporated many new expensive techniques, including spray-foam insulation, we were hoping to do a little better than that. The HERS Index of our first certified green home was only slightly better than that of our first Energy Star home.

Looking back, instead of installing expensive spray foam in 2x4 walls, we probably should have put the money towards 2x6 exterior walls, increasing the overall R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of the assembly.

Besides the high cost, another drawback of spray foam is the amount of extra foam that is shaved off the wall and ends up in the Dumpster. The scraps end up in a landfill where they remain forever. We were trying to reduce waste and recycle our trash to divert it from the landfill, but we ended up using a product that is inherently wasteful.

The extra costs for the closed crawl space, spray foam insulation, certification, and other details added up to about $20,000 more than we typically would have spent.

Unfortunately, when it came time to sell the home, nobody seemed all that impressed with our green building certification. That made it hard to charge extra for.

We still learned a lot during the process, and overall was a positive experience. But we need to educate the masses.

Danny Kelly is a co-owner of Kelly McArdle Construction in Charlotte, North Carolina.


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  1. Danny Kelly

1.
Fri, 09/16/2011 - 23:35

spray foam
by Pat Dundon

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In the article you did not say if you used open cell foam or closed cell foam, but you did say you had a lot of shaviongs that went to the dumpster. that makes me think open cell. in a 2x4 open cell is likely only R-14-15.

closed cell would have added structural suport, made less waste, and given you R-17-19 in the wall cavity. I don't know your climate zone, but adding rigid foam exterior to the studs would have broken all thermal breaks and added dramatically to your score. if you use closed cell foam between 2x4's on 16 inch centers you can use rigid foam sheathing without other sheathing and you do not lose rigidity. the frame supports compressive loads, and the foam stops racking. you do lose some resistance to puncture, but I don't know how much difference there is in that regard.

I get a lot of requests for extra foam between 2x6 studs (going from R-21 to R-30), and I always tell people not to do that, rather go to 2x4 and add the rigid. not many people will make that change though. Spray foam is marketed and written up so well and this is America, more has got to be better, right?


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