
This was Handcraft Homes' first
LEED for Homes project. And, it
was a very exciting project!
The learning curve was tremendous, but we learned so much.
The project was officially
certified by the U.S. Green Building Council on Feb. 5,
2010. Following are links to the main LEED documentation for the
project;
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Project
Summary
►
Simplified
Project Checklist
►
Durability
Evaluation Form
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Durability
Inspection Checklist
Following is a highlight of some of the main green features
this project encompasses.
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Low impact footprint - this structure sits atop poured
cement piers. It does not have a crawlspace or a basement.
This technique is quite common on the Outer Banks or North
Carolina. The main reason this is considered a green design
aspect is that it virtually eliminates moisture problems
which in turn cause issues with mold, mildew and rot.
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Site Development - the house site was designed
from the beginning to be naturalized. In other words, a minimum
amount of grass seeded lawn will be used and indigenous plants
will be allowed to thrive. The goal is is to minimize
disturbance of natural flora and fauna and to minimize the
amount of irrigation needed. This strategy also cuts down
significantly the amount of chemical fertilizers and pesticides
used to maintain the typical green lawn. Last, but not least,
this style of landscaping also minimizes the amount of manual
work needed to maintain it.
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SIPs (Structural Insulated
Panels) - SIPs are simply two sheets of OSB (
oriented
strand board) sandwiching an inner core of foam. The foam
core can be made from EPS (
expanded
polystyrene), which is what we used, or
polyurethane. We were truly impressed with this material. Not only
do SIPs make an excellent insulating medium, but they are also
incredibly strong while using less wood than a traditional,
stick-built wall. We have never worked with a structure that felt so
solid after its completion. More importantly though is how these
SIPs performed in terms of energy efficiency. One of the best
indicators of how well a house will perform is what is called
"air infiltration". This is just a fancy way of talking about
drafts. The LEED for Homes Reference Guide states that "minimal
envelope leakage" (i.e., air infiltration) should not be greater
than 2.5 ACH, or air-changes-per-hour. This is a measurement of
how many times all the air within a house would be replaced in a
period of one hour during a
blower door test. This is a test where all windows and doors
are closed and a fan is placed at one exterior door sucking all
the air out of a house. This house measured at 370 CFM
(cubic-feet-per-minute), or 1.42 ACH, almost half of the LEED
highest-performance criteria. Click the following link to see a
kilowatt-per-hour energy usage graph for this house. The
following appliances are all-electric; HVAC (including backup
heat), range, clothes dryer. Only the hot water heater is
propane gas fired.
Kilowatt-per-Hour Usage Graph
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OVE
(Optimal Value Engineering) - this is a design technique
employed by
Watershed Architects that is aimed at delivering a high-performance structure while
only utilizing minimal amount of materials to achieve the
design. Probably the simplest example of this is building
interior, non-bearing walls with studs on 24" centers, rather
than the traditional 16".
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ERV (
Energy
Recovery Ventilation) - this is a device that is connected
to the ductwork of a forced air heating and cooling system. It
allows fresh air into the conditioned environment while letting
stale air out. It does this while transferring a significant
portion of the energy in the expelled, conditioned air to the
incoming, unconditioned air. In our opinion this device is a
requirement when building a structure from SIPs, because SIPs
provide such a tight building envelope. Without an ERV a SIP
structure would build up excessive amounts of moisture
potentially causing moisture damage.
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Durability Inspection Checklist - this document, required by
LEED for Homes, is way of ensuring that all aspects of a
structure that could potentially cause future problems,
especially in terms of moisture, are adequately addressed during
the panning and construction stages.
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A Host of Other Green Features:
TPO membrane roofing
by
Firestone with high
reflectivity, insulated
windows
with a
u-factor of .34,
Homeslicker Plus Typar house wrap for a truly breathable
outer envelope, countertops made from recycled paper by
Richlite, all lighting fixtures and appliances are
Energy Star
rated, tankless gas-fired hot water heater by
Rinnai, low-VOC paints by
Sherwyn-Williams,
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Our Green Subcontractors - since green building is relatively
new to the residential construction market it is very difficult
to find subcontractors with
LEED Professional Accreditation. However, all of the
subcontractors Handcraft Homes used on this project were very
enthusiastic and cooperative in helping us achieve our goals
under the
LEED for Homes program. Following is a list of the
subcontractors we used;
◊ Laroche Construction (Carpentry): Mike Laroche (804) 467-9369, email:
mLarocheConstruction@yahoo.com
◊ Layman & Son, LLC (Insulation): Mike Layman (804) 640-3894
◊ New Day Corporation (Clearing, Excavation): Clay Edwards (804) 784-0500, email:
newdaycorp@wildblue.net
◊ A/C Mechanical Services (HVAC): Darrell McCauley (804) 382-1111, email:
McCauley_2009@comcast.net
◊ David Warren Company (Plumbing): David Warren (804) 921-5587
◊ Big Wheel Painting: Gene Vincent (804) 763-4237
◊ Hertless Brothers Roofing: Scott Shufflebarger, (804) 340-0181, email:
shuff@hertlessbrothers.com
◊ Water Wells, Inc: Chuck Bush (540) 894-5461
◊ Earth Craft House VA (LEED AP): Sean Shanley (804)
225-9843, email:
sean.shanley@earthcraftvirginia.org