Page 38 - Green Builder Magazine Sept-Oct 2021

Key Features

AIR SEALING: 1.7 ACH 50. an insulated chase in the vented attic. (ACH 50), with exceptional air sealing
Using the building information modeling practices spray foaming the wall cavities,
APPLIANCES: ENERGY STAR refrigerator, tool was “very helpful for getting everyone installing gaskets at the top and bottom
dishwasher and clothes washer. on the same page” regarding schedule and plates, and installing rigid foam blocking
sequencing of trades, and a great help in between trusses at the eaves. All interior
ATTIC: Vented attic: 14-inch R-50 blown-in preparing for crucial pre-construction wall top plates were spray foamed after the
fiberglass on flat ceiling; 18-inch R-65 blown-in team meetings, Wertheim notes. ceiling gypsum board was installed. The
fiberglass in vaulted roof; trusses incorporate In addition to visualizations, BIM soft- floors were air-sealed at the rim joists with
mechanical chase insulated to R-50 with ware can generate a bill of materials and closed cell spray foam where the gasketed
3-inch spray foam and R-30 batt. a critical path schedule that allows labor plates and floor joists meet the foundation
productivity to be tracked at an activ- wall, and all floor-to-floor penetrations and
ENERGY MANAGEMENT SYSTEM: Smart ity and trade level. The software sends bypasses were gun foamed or fire caulked.
thermostat is Wi-Fi and voice controlled. out an automated text message to each The exterior frame sits on 8-inch
individual trade foreman with a simple poured concrete foundation walls pro-
FOUNDATION: Insulated basement: 8-inch question at the end of each workday (e.g., tected with a roll-on capillary break over
concrete walls; elastomeric water proofing; “Is the second floor interior framing 50 the footings, and an elastomeric founda-
2-inch graphite EPS. percent complete? Yes or No?). When tion water proofing on the exterior of the
they respond, the schedule is automati- walls. These are then wrapped with two
HVAC: Ducted and ductless mini-split heat cally updated. If the answer was “no,” the inches of EPS graphite-enhanced foam
pumps; 9.6 HSPF; 15.5 SEER. follow-up question is “what percentage insulation. The above-grade portion of
is complete?” followed by “what was the the EPS is protected with fiberglass-rein-
HOT WATER: Heat pump water heater; UEF=3.7; cause of the delay?” forced panels.
80-gallon central manifold and PEX piping. Every step from that point is automated The main gable roof is topped with
via a simple text-messaging interface. The architectural asphalt shingles over a
LIGHTING: 100 percent LED with motion builder and trade partners receive auto- coated 5/8-inch OSB sheathing product
sensors; daylighting with interior windows. mated construction instructions, and can that is taped at all seams; an ice-and-
see updated schedules. water shield provides additional protec-
ROOF: Truss gable roof: coated taped 5/8-inch tion at eaves and rakes. Two shed roof
OSB sheathing; ice and water shield fiberglass WALL TO WALL sections are topped with highly reflec-
composite shingles; standing seam metal roof. EFFICIENCY tive standing-seam metal roofing over a
A DOE Zero Energy Ready-certified all- full shield coverage. The shed roof tops a
SOLAR: 9.2 kilowatt rooftop panels. electric home should be low maintenance, vaulted ceiling with 18-inch parallel chord
and this one is, according to Wertheim. roof trusses at 24 inches on center, along
VENTILATION: ERV separately ducted; indoor air The home’s walls are sided with an easy- with 14 inches (R-50) of fiberglass loose-
quality sensor; MERV 13 filters; dehumidifier. care engineered wood siding product. fill insulation. The gable roof has raised
The walls are constructed of 2-by-6 studs heel roof trusses to allow full coverage of
WALLS: 2-by-6, 24-inch on center, R-33 total: installed at 24 inches on center. They the 18 inches (R-65) of blown fiberglass
closed cell spray foam plus blown fiberglass; incorporate advanced framing techniques over the top plates in the vented attic.
1-inch rigid EPS topped by 1/2-inch OSB; to reduce the amount of lumber needed This attic space lies over a flat ceil-
textured house wrap; spruce and engineered and to provide more room for insulation. ing in the second floor and has uniquely
wood siding and trim. A 1.125-inch graphite-enhanced designed roof trusses that provide a
expanded polystyrene (EPS) rigid foam 2-by-4-foot attic chase just large enough
WATER CONSERVATION: EPA WaterSense insulation board wraps the studs, and is to house a ducted mini-split heat pump
fixtures and toilets; drip irrigation; driveway. covered with half-inch oriented strand with short ducts that reach to the sec-
board (OSB) sheathing that is installed ond-story bedrooms. The chase is made
WINDOWS: Thin triple-pane, argon-filled, with 3-inch construction screws for of 5/8-inch drywall and encased in
low-e2, vinyl, casement style, U=0.18, SHGC=0.22. increased wind resistance in this high- 3 inches of closed-cell spray foam plus
wind-zone location. A coating of closed- R-30 of batt insulation, for an R-50
OTHER: Accessibility features; all paint is low- cell spray foam is sprayed on the inside insulated and air-sealed chase that is
or no-VOC; CARB compliant wood; walls are face of the EPS in every wall cavity. The thermally connected to the living space
“flash” sealed with spray foam, which also seals rigid foam, spray foam and blown fiber- of the home. A second ducted mini-split
the attic ventilation baffles to the top plates. glass in the wall cavities provide a total heat pump in the conditioned basement
wall insulation value of R-33. serves the main floor. Both heat pumps
The builder achieved a low air leakage have a heating efficiency of 9.6 HSPF and
of 1.7 air changes per hour at 50 Pascals cooling efficiency of 15.5 SEER.

36 GREEN BUILDER September/October 2021 www.greenbuildermedia.com