The ROSE Cottage Project
Completion
Occupancy
Owner occupied.
2.5 ave occupants.
24 hour occupancy.
Scope
Located in a rural neighborhood section of the capital city of Concord, New Hampshire, this multi-generational, aging-in-place house demonstrates how a zero net energy, sustainable residence can be built within a reasonable budget to incorporate multiple themes of long life cycle value. One of the first zero net homes in northern New England, the house occupies a 2.12 buildable footprint surrounded by 6.74 acres of conservation easement land along the shore of Turtle Pond. The project is comprised of two separate structures connected by a 70-foot diameter courtyard. The house and attached two car garage follow the natural sloping terrain facing south-east with views towards the pond, woodlands and wetlands. Three distinctive rectangular volumes make up the garage, main living space, and bedroom wing; accented by a timber framed, gable main entrance that offers transparency and a visual link to the pond beyond. Off the rear of the main living area are two timber trussed, gable roof spaces each extending 16’ out from the rear of the home, which are elevated and connected by an open wood framed deck. The first enclosed space is a 14’x16’ 3-season room which shares a common 12’ NanaWall folding/sliding glass door assembly with the dining area. The second partially enclosed space opens off the foyer/main entry onto an open deck and sunken spa that is contiguous with the open connecting deck. The lower level of the home is below grade on three sides, with two at-grade entrances from the rear, and is washed with natural light from oversized windows and sliding glass doors facing the pond. The detached carriage style garage faces north and its long sloping roof to the south supports 60 photovoltaic solar panels, yet nestles itself comfortably into the sloping terrain on two sides.
| Type of Construction | New |
|---|---|
| Number of buildings | 1 |
| Floor area of each building | 4,100 |
| Bedrooms | 3 |
| Bathrooms | 2.5 |
| Stories | 2 |
| Conditioned Building Volume | 45,740 cu ft |
| Conditioned Floor Area | 4,100 sq ft |
| Semiconditioned Floor Area | 200 sq ft |
Location and Climate Details
single-family residence
| Address |
Appleton St Concord, NH 03301
United States |
|---|---|
| Location Type | Rural |
| Climate Region | Zone 6 |
| Köppen Climate Type | Dfb |
| Lat. / Long. | POINT (-71.5158139 43.247425) |
| Elevation | 337 ft |
| Solar Insolation | 4 kWh/m2/day |
| Annual CDD and Base Temp | 754 | 65 deg F |
| Annual HDD and Base Temp | 7140 | 65 deg F |
Site
Situated on a formerly overgrown section of farmland and scrub woodlands, the site offered no naturally flat or attractive terrain within the buildable area limits of the 8.86 acre lot. The best buildable land on the lot was preserved as open farmland through a conservation easement. The vast majority of the trees cut for project development were not commercially viable and were converted on site into woodchips that were used for erosion control berms and ground cover stabilization. All of the topsoil removed for project development was stockpiled, sifted, and then converted into loam for use on the project, and the surplus loam was exchanged by the site contractor for other gravel materials required for driveway construction. All large stone removed during the project excavations were extensively re-used later as free standing stone wall construction, vertical stone retaining wall construction, and inclined slope “armoring”. All small stone, stumps, and farm debris were buried on site as common fill.
The finished site design extends the green pasture lands to the east, down to the new access drive, and new grasses flow into the upper terrain of the vegetable and perennial gardens. These areas were previously scrub woodlands, tangled and overgrown bushes and vines, and farm debris. The newly created tiers of the project layout and design extend over four distinct levels: the upper natural grade fields and gardens; the driveway, first floor residence, and garages (2) at-grade access; the lower level floor at-grade access and septic field/lawn; and the lowest level natural grade of woodlands and grasses. The two at-grade levels of the house design embrace the naturally sloping terrain and are integral to both the economics of “earth berm” construction and zero net energy performance.
Large prominent trees consisting of maple, white oak, red oak, eastern pine, shag bark hickory, and pignut hickory have been painstakingly preserved within the project’s buildable area. All species of trees and shrubs are preserved within the conservation area. Some of the existing species of softwood trees and natural grasses were also transplanted within the newly landscaped areas of the project. Native species were also purchased from New Hampshire nurseries. A small orchard of mixed semi-dwarf varieties was planted on gently sloping terrain that would otherwise be unused, as it connects the upper main access drive, the side drive that provides access to the lower level in the rear, and the lower level lawn/leaching field. All new lawn areas and grass field extensions were seeded and grown in-place.
A comprehensive stormwater runoff collection and redistribution design was implemented to make sure that pocket wetland areas below the site would be properly recharged. A compliment to that strategy was to divert some of the upper level roof runoff directly into a perimeter drain system of the house that must first saturate a 2,500 sf +/- area of a 12” deep sand bend layer that houses some 7,500 lf of “slinky” solar-geothermal hybrid ground loop lines, before exiting the perimeter drain system.
The home is accessed via a 700'+ long x 18' wide gravel drive. The width was increased to 18' to accommodate two-way traffic. At the terminus of the gravel driveway (carriage garage location) it transitions into concrete panels that connect the driveway, house entry, attached garage, and detached garage via an approximate 70' diameter “courtyard”. Drainage from the concrete pitches to a catch basin located on the western edge. There is ample room for snow removal and snow storage along the easterly side of the courtyard.
The full perimeter of the home is accessible via a (minimum) 12' wide gravel access drive with a maximum 10 degree slope, which is suitable for winter travel by front wheel drive or all-wheel drive vehicles. The adjacent pond is accessed by a 6' wide gravel trail suitable for walking and also accessible by an ATV or garden tractor. There is a 10'x10' wooden platform at the shore of the pond with a dock connected to it in the summer. The pond is accessible for recreational use all 12 months of the year.
Materials and Design Strategy
Materials were selected based on a number of criteria, but in general reflect the long life cycle nature of the home’s design, due to the multiple themes of zero net energy performance, aging-in-place life planning, and multi-generational living, all of which have a potential long ownership plan associated with it. Durability and low maintenance held a particularly strong place in that field, but they also play into the themes of our sustainable, recycled and/or recyclable, and green criteria as well. For example, long life CertainTeed products were used for roofing, siding, trim board, decking, railing and soffit applications. We also took advantage of locally sourced products wherever possible, but never to the detriment of life cycle. For instance, all the ground covers (bark mulch or wood chips) were either created on site with site materials or made 25 minutes away from wood waste products. Also, our large architectural timber frames, timber trusses, and wood beams were fabricated by Thurston Millworks, a millwork shop just ¼ mile away, from domestic, sustainable forest timbers.
Interior/exterior materials include US made, high recycled content porcelain tile flooring by Stonepeak Ceramics for long life and low maintenance; painted concrete flooring, integral colored concrete flooring; Greenguard certified cabinetry by Executive Cabinetry; a small zero carbon footprint manufactured outdoor spa tub by Hydropools; and zero VOC paint finishes by Glidden Professional. US made interior hardwood doors, stair parts, hardwood flooring, hardwood work benches, and office work benches all came from Baird Brothers Fine Hardwoods, a company that heats and cures with its own wood wastes and generates its own electricity from a methane gas field.
On the site wood waste, cardboard, and loose metals were not permitted in the dumpster. All wood was cut for use as space heating or recycled into site (bark mulch/wood chips) landscaping products. All cardboard and metals were hauled to local recycling centers.
The project is comprised of two separate structures connected by a 70-foot diameter courtyard. The house and attached two car garage follow the natural sloping terrain, facing south-east with views towards the pond, woodlands and wetlands. Three distinctive staggered, rectangular volumes make up the garage, main living space, and master bedroom wing (with 9 thermal solar panels on the roof); accented by a timber framed, gable main entrance that offers transparency and a visual link to the pond beyond. Off the rear of the main living area at the upper level are two timber trussed, gable roof spaces each extending 16' out from the rear wall of the home, which are elevated and connected by an open wood framed deck. The first space is an enclosed 14' x16' three season room which shares a common 12' folding/sliding glass door assembly with the dining area. The second space, housing a sunken spa, is a 14' x 20' roofed deck area that is accessed off the foyer/main entry and is contiguous with the open deck connecting to the three season room. The lower level of the home is below grade on three sides, with two rear at-grade entrances, and is washed with natural light from oversized windows and sliding glass doors facing the pond. Radiant floor heating is incorporated at both levels and is powered by a 2T geothermal heat pump. The detached carriage style garage faces north and its long sloping roof to the south supports 60-230W photovoltaic solar panels, yet it nestles itself comfortably into the sloping terrain on two sides with raised concrete foundation walls.
The envelope of the house is super-insulated with R40 value upper walls, R27 value lower walls, and R60 value roofs. The upper walls are double 2x4 at 24” on center, wood stud walls separated by a 3.5” cavity. The outer wall and cavity have 7” of dense pack cellulose insulation and the inner wall is insulated with 3.5” of rockwool insulation. The lower walls are 8” Logix ICF concrete walls with 2-3/4” of high density foam on each face. The roof trusses have a minimum of 24” of blown-in cellulose insulation. Under the lower level 4” slab-on-grade is 6” of EPS foam insulation which is R22+. The roofs are all pitched using prefabricated roof trusses that allow for a minimum of 24" of blown in cellulose. The top chords are extended using supplemental on-site lumber to create a standardized 24" overhanging soffit for summer shading and continuous air flow to the ridge vents. Likewise, the gable ends receive similar treatment to provide a 24" shading overhang.
Heating and cooling are provided by two Bosch 2 ton ground-source heat pumps connected to a horizontal ground loop system. One heat pump is a Bosch water-water model and the other a Bosch water-air model. The water-water unit is solely devoted to heating the ten zone radiant floor system on two floor levels, a Runtal hydronic towel warmer/radiator in the master bath, and the 198 gal Bosch/Buderus PL750/2S Solar DHW/Space Heating Combi Tank. The solar tank is kept at a minimum of 100 deg F by the heat pump during periods of poor weather. The water-air heat pump serves a single upper level ducted distribution system that has operable adjustment dampers in the ductwork to allow the owner to create both warm and cool spaces. The upper level air system is controlled by a centrally located “smart” Ecobee thermostat and a mechanical room Ecobee control panel, which is also accessible on-line via a PC or smart phone app, to provide both heating and cooling control at all times. Nine of the ten radiant zones are controlled by simple heat only wall thermostats, and the largest open space 1st floor zone is controlled by the Ecobee thermostat which decides how best to heat that zone (i.e. - capable of running both heat pumps simultaneously).
Domestic hot water is generated by a 9 panel (28,000 btu/day/panel capacity) Bosch/Buderus Logasol SKS 4.0 flat plate collector solar system that stores energy in the 198 gallon Bosch Combi storage tank in the lower level mechanical room. Whenever the solar hot water is below 120 deg F, a Seisco on demand electric water heater boosts the water coming from the hot water tank to approximately 135 deg F before reaching a final tempering valve. The solar panel system panels are also utilized to form a solar-geothermal “hybrid” system, such that once the solar storage tank reaches peak temperature (160 deg F in summer), the hot glycol coming from the panels is diverted through a stainless steel heat exchanger via a Bosch/Buderus TR0603 Solar Controller to heat a small buffer storage tank up to 120 deg F. The buffer storage tank is also heated by the 2 ton water-water geothermal heat pump and serves the radiant floor heat system on both levels. The buffer tank temperature is automatically maintained by the heat pump to between approximately 90-110 deg F, based upon the outdoor temperature. When the buffer tank is in active heating mode during the winter season, the BTU’s from the solar glycol go directly into the space heating needs of the radiant floors when not heating the solar tank’s domestic hot water supply. If the buffer tank reaches its maximum heat setting of 120 deg F, the hot glycol feed is then diverted into (13) 300’ long horizontal ground loops that dispense BTU’s into the 12” deep, saturated sand geothermal bed to boost the energy available in the bed. The (13) 300’ long geothermal ground loops are separated vertically from the glycol loops by 4” of wet sand. When the glycol temperatures (usually lower than 115 deg F) are too low to either heat up the buffer tank or solar tank, flow is automatically diverted into the sand bed (“solar dump”).
Materials were selected based on a number of criteria, but in general reflect the long life cycle nature of the home’s design, due to the multiple themes of zero net energy performance, aging-in-place life planning, and multi-generational living, all of which have a potential long ownership plan associated with it. Durability and low maintenance held a particularly strong place in that field, but they also play into the themes of our sustainable, recycled and/or recyclable, and green criteria as well. For example, long life man made products were used for roofing, siding, trim board, decking, railing and soffit applications. We also took advantage of locally sourced products wherever possible, but never to the detriment of life cycle. For instance, all the ground cover (bark mulch or wood chips) were either created on site with site materials or made 25 minutes away from wood waste products. Also, our large architectural timber frames, timber trusses, and wood beams were fabricated by a millwork shop just ¼ mile away, from domestic, sustainable forest timbers.