Cooper's Hawk Terrace
S/F: 32’ x 72’ – each unit 2304 per duplex/1152 per unit
Panel Size: 6” GPS Walls/6” GPS Roof, over R-15 batts in the top chord of trusses
Why SIPs: Premier SIPS provide superior insulation and air-sealing while eliminating the need to vent the attic, which is a big deal when it comes to the Wildlands-Urban Interface Code. Construction time was also a factor, as site labor is increasingly in short supply.
Innovative Design Elements: The SIPS over-truss construction allows longer spans while keeping some attic space for ductwork and fire suppression systems. The use of R-15 batts in the top chord of the truss beneath the R-28 SIPS panel gives us a well-air-sealed R-43 assembly, with no thermal bridging. Gable end walls go all the way to the bottom of the SIPS panel, which provides all the overhangs, without requiring additional framing.
- The total envelope heat loss for the duplex was 13,581 Btuh on the design degree day. This would represent an energy intensity of 5.895 Btu/sf.
- Each unit uses a Mitsubishi Ductless heat pump for heating and cooling and features a tier-3 heat pump water heater for domestic hot water.
- Vinyltek triple-pane windows were used, with low SHGC and a U-value of .16
- All appliances had the lowest energy use in their respective categories.
- 100% of lighting is LED.
- The homes were designed to receive maximum benefit from their passive design.
- Water heating, mentioned above, is at a Co-efficient Performance of 3.35
With solar panels on the garages only, these units will completely power themselves and the owner’s cars (two cars per unit at 10,00 miles per car per year). With the entire south-facing roofs fitted with solar panels, these 18 residential units would power themselves, AND an additional 54 average existing homes in the neighborhood.
Exteriors are all Hardi-plank, Hardi-panel, and Hardi-trim, for fire-proof exteriors. The roofs are all steel standing-seam roofing, for the same reason. The finished floors are all dyed concrete.
The 6" GPS roof panels were set on standard trusses. There is no overhang on the trusses and no bird-blocking...only solid blocking between trusses in accordance to the Wildlands - Urban Interface Code. The bottom chord f the trusses provides a fully enclosed attic completely inside the SIPS building envelope, with only the ends of the trusses needing to be spray foamed.
The required sprinkler system is free to run along the bottom chord of the trusses. The combination of Hardi-Siding and Hardi-Soffit along with all the tempered glass in the windows and the steel roofing provides a fireproof exterior shell. This is something to be touted widely.
Ted Clifton Quote “PG&E, get out of our way!!!”