Cambridge, MA
In this photo, the Phase II gut-rehab section in the foreground is now high performance and integrates with the Phase I right hand portion of the home. Note the two-panel solar thermal system, which provides the lion's share of the home's domestic hot water needs. The vertical bare wood pillars in the foreground are part of a trellis-hand rail detail for the corner deck, still under construction.
This footing to ridge detail shows the two eave and one gable cross section of the Phase II portion of the Newman-Slaughter gut rehab. The differences in the north and south elevation configurations are to align each wall with Phase I walls with which they must match up.
General Specs and Team
Location: Cambridge, MA
Bedrooms: 5
Bathrooms: 3
Living Space : 2860 sqf
Cost (USD/sq. ft.): $250/sqf
This cost is for the Phase II work, approximately 1200 square feet.
Project Leader: Jim Newman, BuidlingGreen
Builder: Fenton Inc. Custom Builders
Architect: Next Phase Studios
Solar: CAPCO Energy Supply
LEED for Homes & Energy Consultant: Mark Price, Steven Winter Associates
Construction
Basement: Concrete block, Icynene open-cell spray foam between floor joists
Above-grade walls (Phase I): 2 by 6, 5.5-inch fiberglass batt, 3/4-inch Polyiso rigid exterior insulation
Above-grade walls (Phase II): Various thicknesses of exterior and interior rigid EPS and 3.5-inch Icynene cavity fill
Attic: 7.5-inch Icynene rafter cavity fill insulation + 4 inches of interior EPS rigid board insulation (plus 2 by 4 strapping)
Energy
HERS score: 80
Heating Degree Days: 5200
Cooling Degree Days: 1050
Solar: Caleffi Rooftop solar hot water system
Cavity Insulation: Icynene spray foam
Rigid insulation: EPS
Attic R-value: 41
Above-grade wall R-value (Phase I): 24
Above-grade wall R-value (Phase II): 27 - 30
Basement R-value: 22
Windows: Accurate Dorwin Fiberglass (U-value=0.21; SHGC=0.26; VT=0.45)
Water Efficiency
Inside:
Toilets:Toto throughout
Faucets & showerheads: Delta WaterSense lav faucets and Symmons showerheads (with flow restrictor) throughout
Clothes washer:Whirlpool h-axis clothes washer
Dishwasher: LG
Outside:
Irrigation system: none
Rainwater harvesting: Berg Pillow Tank (under back deck)
Indoor Air Quality
Mechanical Ventilation: Lennox Healthy Climate Solutions HRV-3 200
Spot Exhaust Fans: Energy Star Panasonic
Interior Finishes: Benjamin Moore Natura; SafeCoat PolySeal floor finish
Contaminant Control: block off HVAC during construction, walk off features at entrances, shoe storage
Green Materials and Resource Efficiency
Reclaimed: foundation, floor framing, interior & exterior wall framing, cabinetry, finished floors, interior trim, roof/wall/floor sheathing
Jobsite Recycling: > 75% (wood, rubble, carboard, metals)
Framing, Sheathing, Siding and Trim: FD Sterritt FSC-certified wood building products
Certification
USGBC LEED for Homes Silver (pending)
Planning ahead, using the same design team, and comprehensive whole house performance evaluation all keys to this unique 10-year LEED for Homes project
Don't all major home renovations span decades?
Jim Newman and Sarah Slaughter bought a rather pedestrian Cambridge home in 1996 and began full renovation in 2001, recently completing the metamorphosis in 2010. They have always taken the long view on both the environment and their own home's performance. As building professionals in their own right, Jim and Sarah worked closely with NPS Studios and their contractor on the energy and resource efficiency aspects during BOTH phases of their whole-house renovation.
Can the Newman-Slaughter two-phase gut rehab LEED for Homes qualify?
"It's a special project that will qualify," says Mark Price, Senior Sustainability Specialist with Steve Winter Associates, a LEED for Homes AP and rater. Mark feels pretty strongly that there are five aspects of this project that justify treating this two-phase project as a single one:
1. Existing comprehensive documentation – "Jim and the design/construction team took detailed and numerous photos of open-cavity walls and roofs, had a full set of plans, and specifications for Phase I," says Mark. "If I can verify everything from Phase I, I can count it."
"I think we spent three straight hours pouring over the photos and nailing down just exactly where the building envelope (thermal barrier and air barrier) was, how Phase I and II elements lined up," says Jim.
2. Same design firm - "We always had a two-phase plan with NPS Studios," says Jim. "We just did not know exactly how closely (or not) Phase II might follow Phase I. And since LEED for Homes did not exist during Phase I, it was a really interesting opportunity to see if what we had accomplished in Phase I could dovetail with Phase II to make the whole project eligible for LEED for Homes."
3. Extensive performance testing of Phase I – Working with just an infrared camera to start, and then adding steady depressurization of the home with a blower door to exaggerate thermal and air barrier short circuits, Mark and Jim carefully identified places in Phase I that would need to be addressed as part of Phase II. "There were not a lot of them, but they were significant," explains Mark. "But Sarah and Jim made the commitment to pull the entire home's performance up to the LEED for Homes standards."
4. Conservative assessment – Jim agreed with Mark's decision to essentially give all of the Phase I details, such as quality of insulation, a conservative rating (grade II – a less than perfect installation).
5. Phase I changes as part of Phase II – Sarah and Jim went through the LEED for Homes rating system line by line with Mark Price. For example, when they got to the existing masonry fireplace, Mark was unsure about how they would feel about adding operable doors, a LEED for Homes prerequisite. Jim relates," Actually, we had wanted to add airtight doors since we put the fireplace in and all we needed was this push."
Not all of the resolutions required were quite that easy. When the performance testing indicated that air sealing and insulating on Phase I living room eaves would mean taking down the soffit and spray foaming that whole area, that is no small project. "It's not easy to pile on that sort of effort and expense," remarks Jim. "But the question is: is it worth it? And we decided the answer was yes because it made our home more energy efficient, comfortable and durable."
Mechanical serendipity
During Phase I, NPS defined a zone heating and cooling system, and the HVAC contractor decided to install two 3.5-ton AC units. One services the downstairs with ducts and air handler in the unconditioned basement, and one services the upstairs from the unconditioned attic. Seven tons of cooling for less than 3,000 square feet in a cold climate! Problem or opportunity?
"Good question!" quips Jim. LEED for Homes requirements would mean eliminating the ducts and air handler in the unconditioned basement. Could the upstairs unit (now inside the insulated unvented cathedralized Phase I attic) provide sufficient comfort throughout the whole house, directly conditioning the upstairs and indirectly the downstairs? "After the Phase II improvements, the whole house loads can now be served by a single unit," adds Mark.
"We have now had some real-world testing of just the upstairs delivery and it does fine for the open areas (living room, dining room, and kitchen) but more tweaking is probably needed to provide sufficient comfort in the two separate downstairs rooms (library and bedroom)," says Jim. "The redistribution accomplished by the whole house ventilation system is key to this. Probably just use the second 3.5 ton compressor as an in-place spare," Jim says with a smile.
Using LEED for Homes: point chasing or informing the process?
For Jim Newman and Sarah Slaughter, there is just one way to use any rating system. "It informs, not drives the process," states Jim. "We developed a package of water, energy, and resource efficiency features for our home renovation and used the LEED for Homes prerequisites and credits as just a double check. The points and rating are what they are."
But if you look at the extensive features in the project detail sidebar, Sarah and Jim ended up with a high performance home; it just took a while to get there.
Lessons Learned
Jim and Sarah are generally pleased with the way their two phase renovation has worked. Jim summed it up this way. "We did what we could at each stage, living pretty much in each section of the house as the other was gutted. We could have ended up with lots of disconnects because of the two-phase approach, but the upfront time spent on planning and sticking with the same design firm really paid off."
That said, Jim identified three main issues he would have liked to do differently or get a second strike at with hindsight.
The flashing details
Without the details drawn up or mocked up ahead of actual construction, the inevitable job site pressure meant that some details were either created or just simply installed on the fly. "Even the best of us sometimes needs breathing space to chew on what we are doing, and we missed that," says Jim.
The A/C and ducting issues
Jim again: "We absolutely should have hammered this out before we started Phase II work. It worked out ok, but more by happenstance than by design. We could have saved a lot of grief and head scratching if we had dealt with the issues of loads and duct runs and equipment location ahead of construction."
Planning for water harvesting
While Jim and Sarah knew they wanted to set up a rain water harvesting system (to fill the pool and eliminate irrigation needs), they needed to know much earlier in their planning about just how much space is required to store the amounts they get off of their roof. "It's easy in the wet northeast to treat water harvesting as a bit of a late term add-on. But while it is easy to take the amount we get or granted, STORING it is NOT something to take lightly!" says Jim.
When asked about the LEED for Homes experience, Jim does not hesitate: "Definitely worth the time and the effort and the expense. We have a much better home because we went through the LEED for Homes rating program and process. The documentation is definitely a pain in the butt, but it's part of the process that connects design, materials and construction, in a good way."
Peter Yost
--
Scott's Contracting
scottscontracting@gmail.com
http://www.stlouisrenewableenergy.blogspot.com
http://www.stlouisrenewableenergy.com
scotty@stlouisrenewableenergy.com
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ReplyDeleteYou offer a lot of great information on this topic. I agree that there are a number of benefits to exterior insulation. It is a great idea to at least look into these kinds of improvements. However, before beginning an improvement like this, it is truly essential to do your research. I like to use McGraw Hill's Sweets Directory of construction products. Though I work for them, they honestly offer a lot of important information, as well as some great CAD details that you can download from their site. They are really worth taking the time to check them out.
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