A building consultant practices what he preaches by retrofitting his home for healthy and productive living
When Dan Cote bought this run-down property on Woodstock Avenue in Portland, he wanted to take everything he had learned about high-performance building and building science from his day job as a technician and consultant for and pack it into the structure and the lot. He pretty much lived in the middle of his work for the next several years.
Beauty and building science
Perhaps the most striking aspect of Dan’s project is how well he has combined all the technical details with a truly beautiful home, inside and out. From color schemes to flashing details, from plant selection to thermal bypasses, Dan’s home and lot show both right and left brain prowess.
On the outside, Dan dreamed up the eave-overhang green roof. “I spent a lot of time looking at my beautiful secondhand Doug fir doors out back, wondering how I could protect them without an overhang so low that it becomes all that you see,” Dan relates. “In the end, I decided, why fight it; do something attractive on the overhang.” The result is planter boxes full of hardy sedums, minimally attached and flashed in such a way that it does not affect the water management capacity of the roof. “The overhang is a stepped-down add-on to the roof, completely separate. I used a self-healing membrane on the overhang, gooped [sealed] each of the six fasteners securing the planters, and then left the soffit open to dry readily.”
On the inside, Dan’s big thing is durable, low-maintenance floor surfaces. “I really liked the pre-finished bamboo because it is a rugged, low-maintenance material, but I thought the kitchen needed something a bit more interesting as well,” says Dan. With a box full of tile odds and ends, Dan began planning a mosaic right in the center of the kitchen floor. Dan chuckles: “It was like doing a puzzle without the picture on the box.”
Dealing with a “hammock” roof
It is not uncommon for the rafters in old bungalows like Dan’s to be grossly undersized. His rafters were rough-cut 2x4s that sagged nearly two inches in the center. Dan got all but about 3/8 of an inch back in two ways: having each rafter bear directly on the new knee-wall studs (reducing the length of the rafter runs) and sistering both sides of each rafter with plywood gussets.
A tough flashing detail at the bathroom corner window
Dan’s downstairs bathroom has a nifty two-window corner off the back side of the house. The problem is that the back window on the corner is less than a foot from where the back addition roof intersects the main part of the house. This meant that getting the water-resistive barrier and window flashing details and interconnection right was critical for water management. Dan said, “With the housewrap interior to the exterior rigid foam insulation, it was pretty easy to tie the window flashing and WRB together. Then tucking the kick-out flashing behind the step flashing, which were tucked under the WRB, sealed the deal.” Dan mocked all this up ahead of time, including a change in exterior cladding just above this window, to make sure he had it right when the window and housewrap were installed.
“Habitat for Hu-Dan-ity”
So Dan really did all this work in his spare time? Not entirely; Dan is a creative guy and conjured up his “Habitat for Hu-Dan-ity” work crew. You invite your best and most loyal friends over for beer, barbecue, and building. It’s sort of a dude ranch for building science; Dan gets a bunch of free labor and they all get some on-the-job training they can use on their own projects. This explains quite a bit about how low Dan’s cost per square foot is for this gut rehab. Dan scratches his chin and adds, “I suspect that my total project cost might double if we factor in the real labor costs.”
Dan’s lot is as high performance as his home: about 1,000 square feet of his 7,500-square-foot lot is raised beds of vegetables and fruits:
- Three varieties of squash, including Dan’s favorite,
- Four varieties of tomatoes, including , , and
- Three varieties of potatoes
- Garlic onion
- Bok choi
- Full complement of herbs
The raised beds are elevated by at least six inches of local compost and top soil so that Dan essentially is growing above (not in) the untested urban soil below.
The main lesson learned for Dan was about the insulation package for the exterior wall assembly. "I used closed-cell spray foam in the wall cavities, and THEN learned the advantages of warming the cavity with rigid exterior insulation," quips Dan. "If I could do it over again, I would definitely use a loose insulation such as cellulose for the cavity fill, and go with the taped rigid as my exterior air barrier."
General Specs and Team
Completed: March 2010NOTE: Square foot cost would likely double to reflect true labor costs.
Remodeler: Dan Cote,
Foundation: Basement; new, sistered, strongback foundation section (to handle the lack of footer); medium-density spray-foam insulation (Froth Pak)
Walls: 2x4 studs at 16 inches on-center; exterior 1.5-inch XPS plus closed-cell foam cavity insulation (R-27)
Roof: 4x4 (plywood gusset sandwich) rafters at 16 inches on-center; 30-year shingles; unvented; closed-cell foam insulation (R-25, SWD Urethane)
Windows: low-e wood-clad (SHGC=0.24; U-factor=0.38)
- Toilets: 1.6 gpf with tank retrofit
- Faucets: 1.5 gpm (original faucets with aerators)
- Showerheads: 1.0 gpm
Indoor Air Quality
- Spray foam insulation (formaldehyde- and VOC-free)
- Fresh air ventilation system: ERV (basement and first floor; timed high-efficiency exhaust second floor)
- Low-VOC caulks and adhesives
- Low-VOC paints
- Re-purposed, original finish cabinetry stock
Green Materials and Resource Efficiency
- Rigid XPS insulation: reused/salvaged, purchased online
- Durable, low-maintenance floors throughout: tile, slate, refinished Douglas fir
- Retained most of original framing
- 75% of construction waste recycled