|2006 National Association of Home Builders National Green Building Awards Finalist [Construction Details] [View the Blueprints ]|
When people hear that we took second place in the 2006 NAHB National Green Building Awards with this house we usually get a "What makes this house so green?" type of reaction. The fact is that this house isnít built of straw bales and doesnít have any solar panels on the roof. The elements that make this house green are as numerous as they are subtle. When Beth and I were designing this house we were not aiming to win national recognition, we were just trying to use the most energy and resource efficient systems to build the most beautiful home we could for a price that is sustainable for the family that is going to live there.
A top priority is to make it energy efficient so we used many different strategies enumerated later in this discussion to conserve energy both in the heating and cooling of the house and in the embodied energy content of the materials that go into the construction. The house is an Energy Star Home and was certified by Southern Energy Management to use 30% less fuel than required by the NC state energy code. (www.southernenergymanagement.com ) Their computer modeling of a home allows us to accurately predict the energy performance of the house before it is built so we were able to see that the energy efficient Rinnai demand water heater with an advanced recirculating hot water system would require only $140 per year to supply the domestic hot water for the home and that it would be better to invest in a first class wood stove than to put a solar water heater on the roof. After the house was built we had Southern Energy Management come out and perform a full daignostic testing on the house including blower door testing and duct blaster testing. The house received a HERS score of 89.8 which equates to 49% better than code. By comparison a house is considered Energy Star certified if it scores 30% better than code.
We also wanted to make the house a healthy house to live in so we followed the NAHB's Green Building Initiative Guidelines in minimizing carpet and using low VOC finishes when possible. We also used a tented crawlspace system discussed later as well to keep clean dry conditioned air under the floor while also allowing humidity and radon to escape from the soil under the house through a pipe to the roof. This house acheived a gold rating using the new NAHB Green Building Initiative rating system. Scroll down to the bottom of this article, past the blueprints, to see detailed explanations of how these systems work.
In the final analysis I think the reason this house received the national recognition that it did is because all the elements we utilized to improve the performance of this home were low cost and high value per dollar elements that could be adopted easily by any builder in America. The theme of this conference and of the NAHB's Green Building Initiative is to "Mainstream Green." Many of the "demonstration green" homes we are seeing are in the 200 dollar per square foot range and cost 800,000 to well over a million dollars to house a single family. It is hard for me to reconcile the word sustainable with a home that costs a quarter million dollars per occupant. This house was built at a price that is affordable for a young family with two kids that just needed a roof over their head that suited their lifestyle and fit their values. What this house really represents is an attempt to maximize Green for your green.
We don't set out to build houses to win awards but last winter Beth and I won the NAHB Seniors Housing Council's aging in place design award for new custom home. It got us to thinking that a house could do more than simply support us with accessibility features as we aged. A house can have an influence on our daily lives. It can make it easy to get outside to play in nature with our children and to work in the garden. It can give us a place to exercise, nooks to read in, and places with great acoustics to play music in. A house can give us incentive to turn off the television and gather with friends to enjoy life. If well conceived, a house can actually help to keep us young.
|Climbing structure second floor(Left).
Michael on the structure (Right).
One thought was to try to build some exercise equipment into the actual structure and trim of the house. The original idea was to have grab bars on the ceilings and walls to engage your hands and arms in the way that the grab bars in a boat allow you to use your hands to steady yourself as you get around below decks in heavy seas. At one point we even considered finding some giant boulders in the woods and bringing them into the house as if they were furniture. The three story climbing gym that we ended up with in the center of the stairway actually started as a climbing wall with artificial rock climbing holds attached to tee nuts. But the sculptural look of a net made of oak won out. This thing is held together with tee nuts and stainless steel pan head screws. The fasteners cost more than twice as much as the oak it is made of. There are three "nets" made of 5/4 by 2" oak. The tops are cut back to run with the railings which are made with a top rail of 1 Ĺ" copper pipe and lower rails of 1 ľ" pipe set at the lowest height allowable by code. The whole intent is to make this look much more dangerous than it really is.
|Third floor looking north, belay point on ceiling (Top).
Third floor looking south (Bottom).
We did not want the climbing structure to get in the way of the open feel of the tower yoga retreat. It is a small room and needs to serve several functions. Itís a place to sit out on the balcony and watch the birds and the stars. It has speaker wiring and home theater wiring so it can accommodate a small flat screen monitor for watching the news and movies. And itís a private getaway place for relaxation and reading. The floor is heavily padded carpet made from recycled soda bottles which was installed shortly after these photographs were taken. A belay point on the ceiling is through bolted to the structure of the roof for use with a belaying system or, more likely for attachment of a climbing rope.
The idea of the house may be dominated by the climbing structure but the rest of the home is filled with carefully considered details as wellÖ
|From Stairs looking south. Top of stairs looking north west. The second floor has a modest bathroom with a pedestal sink and two kids bedrooms with built-in box beds. (The kidsí bedrooms were full of moving boxes on the day these photos were taken)|
|From the top looking west (Top).
From the top looking east, and down three floors (Bottom).
The idea of the house may be dominated by the climbing structure but the rest of the home is filled with carefully considered details as well.
|Sandstone chimney with soapstone niche. Mirror behind soapstone creates illusion of depth.|
Entering the home the welcoming foyer has a sandstone and soapstone chimney back that radiates warmth from the Jotul Castine wood stove it encloses. A mirror in the art niche serves to enhance the apparent depth of the chimney and as a hall mirror. Slots in the bottom and top of the chimney allow air to circulate inside the stove niche and out into the front hall. No fan required.
|The chimney is inches from the back of the mirror (Top).
The powder room at the base of the stairs (Bottom).
|The living room looking south east with thickened walls (Top).
Living room niche mimics chimney niche (Bottom).
With as much glass as there was in this house it would have been easy for the rooms to feel exposed. One way to minimize this is to use thickened walls and deep set windows to create a feeling of shelter. This also had an emotional component for the homeowners as the deep set sills and window seats reminded them of their travels to Europe.
From the living room side of the chimney an arch motif repeats in the doors to the Jotul Castine high efficiency wood stove, the arch of the stove niche, the kitchen arch and the hand made range hood. Much of the soapstone in this house was recycled from broken countertops pieces purchased at deep discount. The cantilevered soapstone hearth is supported on three layers of salvaged soapstone and further reinforced by a custom steel shelf just below the topmost layer. Soapstone has wonderful heat retention properties making this a good place to warm up after a cold afternoon bike ride, which is a good thing as the homeowner rides his bicycle seven miles to work and back every day.
|From the kitchen facing south east (Top).
From the kitchen facing west (Bottom).
The kitchen looks out over the living room and dining and down the long east hall through the multi-use breezeway towards the master bedroom wing. From here one can monitor all activity in the home and keep an eye on the driveway as well. An exterior mounted variable speed fan draws air quietly through the custom built copper hood. The copper counter top turns the corner into the open pantry area.
A window in the pantry gives the cook a view of the parking area and a window over the sink looks out towards the screen porch and outdoor kitchen area. The arch over the copper prep area is finished with the same sandstone as the chimney. Small copper shelves hold spices and oils above the cutting boards.
|The screen porch from the south (Top).
In the porch facing south east (Bottom).
The screen porch juts out to the west providing a place to watch the sunset and also shading the dining room from the hot afternoon sun in summer. Wall sconces were folded up on site from 3x10 foot sheets of 15 oz copper flashing and then tossed on a Weber grill until discolored just so. The bulb is held by a $3.50 "jelly jar" fixture, the copper cost about $6.00 per fixture plus labor. Given that there are 18 exterior sconces in this house getting them at an affordable price was a priority.
In keeping with the desire to build a design that would encourage the owners to get outside the house has seven exterior doors on the first floor plus one on the third floor balcony. That balcony has an amazing view out through the trees to the south and is a great place from which to welcome incoming guests to the home.
|Balcony from the west (Top).
Balcony and mudroom door (Bottom).
The balcony is supported on cantilevered joists that run all the way back to the stair tower and are sized two inches larger than required by the engineer. The posts are attached with special galvanized anchors designed to withstand over 300 lbs of lateral thrust at the top of the railing. The red label cedar shingles are not panelized but rather were attached to the house one at a time. They have not been painted and are only protected by the 32" overhangs and gutters. By not putting any finish at all on the siding we dramatically reduce the usage of paint and volatile organic compounds therein and also reduce the long term maintenance of the house by designing it so that the siding will never need to be painted.
|Outdoor shower just outside the master bedroom door (Top).
View of the house from the east, bay is M-bath. shower (Bottom).
Master bath room with soapstone counter & copper sink. Copper flashing replaces the window sill and protects the casing and trim from the shower spray. Angled soapstone shelf and niche provide space for soap and shampoo.
The master bedroom has a vaulted ceiling with a special steel beam over the bed to lighten up the feeling of the room deep window seats and bookshelves provide a sense of enclosure despite all the glass. Broken edge pieces of soapstone create bedside tables.
Our commitment to preserving the native plants and trees has left us with a house that is snuggled between the trees on the site with stone patios almost at floor level on all sides. Our goal was to create a house that lived in harmony on the site to create a place to keep you young and a place to gather with good friends for good food. We wanted to use materials with low embodied energy content to create a modest but joyful home that used a modest amount of resources. But in the end the most important thing is to feel that your clients have what they dreamed of and a little more.
Michael with Rebecca and daughter Lily holding the rubber snake that lead carpenter Frank Mangieri was always hiding around the house as a practical joke during construction. When Rebecca and Aaron visited with Lily she would always look for the snake and in the end the crew decided to give it to her as a parting gift. Now itís one of her favorite toys.Construction Details
View the blue prints .
|Pouring the footings (Top).
View from the old farm road (Bottom).
We recessed the entire Crawlspace four feet or more into the hill top with one 4" pipe for the foundation drain and a second 4" drain for a crawlspace emergency drain under the footing and one 6" overflow pipe above them all sloped to daylight. We poured 10 x 24" footings with two #4 rebar continuous.
The cellar hole is bisected by an old farm road which we used for the driveway. By keeping the drive to the same width as the old roadbed we were able to dramatically reduce the number of trees that had to be cut to insert the driveway and home in the landscape. The old road bed gave us two points of access to excavate and pour concrete thus allowing us to keep the existing native plants and trees from falling victim to the construction process. As soon as the house was backfilled and the disturbed soil was mulched we drilled a well, set up a temporary construction well pump, and ran 700 lf of well pipe and garden hoses so we could drip irrigate the trees to protect them from root shock.
Two, 250 lf counter spiral loops of Ĺ" PEX are connected to a 60 watt Taco circulator pump to circulate potable water 24 hrs per day through the slab which enables the passive solar gain to take advantage of areaís of concrete that are under furniture or rugs for thermal storage. A digital thermostat on the extreme west side of the slab triggers a second 60 watt Taco pump that injects a small amount of hot water on cold mornings to help warm the floor. By locating the thermostat on the west side of the building it is more likely to shut the heat down as the afternoon sun starts to kick in on passive warming of the slab. We poured 5" of 4000 psi concrete over 1" of Styrofoam continuous and stained it just before sheetrock with two different colors of Kemiko acid stain with a wax finish. We held 100 PSI in the pipe during the pour and throughout construction.
|Jake rolling the joists Ductwork in the 16í TJ 2000ís|
We use short small dimension joists on the first floor with a double 2x10 spine to help keep the floor as close as possible to the exterior grade and to conserve lumber. Note that the tented foundation system is already in place less the floor covering. We ran a de-humidifier during construction after the roof was on to dry out the soil under the house and covered the floor with poly at the very end of the project.
The second floor is framed with 16" OJ 2000 steel free open web joists. Not having steel plates meant that we had much less worry about tearing up the wires and flex duct. All duct connections and air handler cabinets were sealed with mastic even though 100 percent of the ductwork is in conditioned space. The air handler for the second and third floors is located in the tented crawlspace with the main air handler.
|Air tightening begins early. Airtight drywall gaskets go in between insulation and drywall.|
Note that the Tyvek is run under the mudsill in slab areaís and between the double top plates so we can later tape the exterior wall Tyvek to these strips to get a really tight draft stopping job. In the framed floor area the poly that is part of the tented crawl is pulled up under the exterior Tyvek and taped in a similar fashion. Later, when the walls are insulated the top plates get fire caulked and wire holes stuffed with rock wool and the inside of the top plates receive a 1" strip of sill seal as a drywall gasket to prevent conditioned air from escaping from the wall cavity to the ventilated attic area.
|Advanced framing worksheet Bent steel flitch engineering|
This is the advanced framing sheet we hand out to our carpenters and to anyone who expresses the least interest. We use it to discuss how we angle our sills to draw moisture away from the windows, the use of open corners, and ladder tees for reduced lumber cost and increased R-value. We use flush headers and single 2x10 headers where applicable but we still think double top plates are critical to get good OSB and hurricane clip nailing in a hurricane zone.
In the ceiling of the master bedroom on this house is a bent flitch hip that enables us to omit the collar ties that would be required without it and gives us a better insulation thickness over the wall than would be possible with a scissor truss hip vault.
To get the quality of insulation we are looking for in an energy star house such as this it is critical to pay attention to details. The back of the bath tub is a place where there can be a very large temperature differential that can cause "air washing" of convective air currents that can compromise the insulation. We minimize this by covering the R-19 insulation with 1" Styrofoam.
|Tented crawl detail Tented crawl, note no tape necessary.|
We like the theory behind sealed crawl spaces but we have concerns about the longevity of a system with so little margin of error that relies on 6 mil poly to last as a perfect barrier to humidity. The tented crawl space system we use is much more tolerant of tears in the membrane. Basically we still put the code minimum foundation vents in the exterior walls using thermally activated "Solar Vents" that close when the temperature drops below 50 degrees but we drape our foundation plastic over 12" galvanized flashing creating a 4" air space between the plastic and the block on the inside of the foundation. We then vent this space up through the attic so that when the roof heats up on a sunny day a thermal pumping action slowly moves humid air out of this tent through the roof and pulls warm make up air in through the foundation vents. This allows the soil under the house to breathe and shed moisture. The crawlspace side of the tent is separated from this air movement and stays warm and dry. Because summertime moist air cannot enter to condense on the AC ducts and cold water pipes every thing stays dry in the summer as well. But if a cable TV guy drags a tool box across the plastic and tears a hole in it itís not a disaster and if a pipe or roof leak gets water under the plastic floor into the soil there is a long term drying action to mitigate the dampness. We have had great success with this system. Since it is less fussy to install (no tape) we also think it is less expensive in terms of man hours as well as compared with a conventional sealed crawl.
|Piping diagram Rinnai Installation, spin pump raised for easier access.|