Deep Energy Makeover: One Step At A Time
General Specs and Team
Location: Brattleboro, VT
Living Space : 1800 sqf
Construction cost: approximately $85,000; roughly 75% of labor was free (homeowner and family)
Construction/wiring: Peter Yost, Christian Yost, Israel Yost, Nathan Yost (sort of a New England version of Brothers Strong)
Plumbing and heating: Temple Plumbing and Heating, Dummerston, Vt.
Architect: Steve Baczek, RA
Walls (first floor): concrete block; uninsulated
Walls (second floor): wood frame; uninsulated
Windows: single-pane double-hung wood
Roof: unvented slope (steeper pitch of gambrelThis is a gable roof with two pitches, the bottom pitch being steeper than the top. The term gambrel is also used to describe the hing leg of a horse, with a angle at the joint that looks like a gambrel roof, or much more likely, the other way around.), vented attic (lower-pitch gambrel); old, loose-fill fiberglass in very poor condition (approx. R-5)
Basement: Uninsulated cast-concrete, broken concrete floor (one section of bare dirt); vented front-porch crawl space with bare dirt; single-pane awning, divided-lightTrue divided light sash have small panes of glass separated by muntins. Because large pieces of glass used to be difficult (or expensive) to make, older houses have windows with two, four, or six small lights per sash. These multiple-light sash are also called "divided-light sash" or sometimes "divided-light windows." windows
Foundation: basement, 3-1/2-in. open-cell spray foam in stud wall (R-12); crawl space, unvented 1-1/2-in. polyisocyanurate insulation board on perimeter walls sealed with approximately 1-in.-thick spray foam, double 6-mil poly sealed to perimeter walls (R-10)
Walls (first floor): 3-in. high-density, closed-cell spray foam on exterior (R-20+)
Walls (second floor): 2x4 studs; 3-1/2-in. fiberglass batt and 1-in. XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation. insulation board (R-17+)
Windows: ;ow-e, double-glazed, wood-framed (U=.33, SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.=.32)
Roof: sloped ceiling, R-19 fiberglass batts with interior 1-in. XPS (total R-24); flat ceiling, interior 1-in. XPS, criss-crossed triple-layer batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. , one fiberglass, two cotton batt (total R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. : 44+); cathedral ceiling in kitchen addition, R-38 polyisocyanurate 5.5-inch SIPs
Garage: detached (no change)
Pre-remodel K-factor (number of heating degree days covered by one gallon of fuel oil): 7.5
Post-remodel K-factor: 15.85
Pre-remodel blower door: > 4,000 cfm @ 50 Pascals
Post-remodel blower door: 1,240 cfm @ 50 Pascals (still working on air-sealing issues)
Annual energy use: 77 MMBtus/yr (pre-remodel not known)
- Vermont Cow Power
- 88% AFUE fuel-oil boiler
- Superinsulated stainless-steel jacketed indirect-tank water heater
- Under-counter LED kitchen lighting
- CFL or hard-wired throughout home (except three cluster fixtures in living/dining room and kitchen
- Energy Star ceiling fan in master bedroom
- No central air conditioning
- Energy Star dishwasher
- Front-loading clothes washer
- Low-flow toilet: 1.0 gpf pressure-assist
- Hands-free electronic kitchen faucet
Indoor Air Quality
- High-efficiency spot exhaust fans in kitchen and baths
- High-efficiency 24/7 whole-house exhaust
- Carbon monoxide detector in basement next to boiler
Green Materials and Resource Efficiency
- Non-paper-faced gypsum board on all walls
- Driveway redone with free-draining, locally quarried bluestone
- All structural wood removed from home during renovation salvaged
- 2x3s (basement) and 2x2s (reclad system first floor) ripped from ReNew salvaged lumber
- All interior trim reused
- Bedroom and kitchen shelving made from salvaged school furniture
An eight-year remodel of a 100-year old house produces a healthy home that will last another century.
When my wife Chris and I bought this nearly 100-year-old home in 2000, we knew we had our work cut out for us: virtually no insulation; original single-pane windows; a failing main bathroom; just four circuits of knob-and-tube wiring; no laundry hook-up; and a dysfunctional 12x12 kitchen with three windows and four doorways. But the pristine original red birch flooring, the rock maple trim throughout, and the double lot on a quiet street seemed to make the whole thing more than worthwhile. And being a building scientist and former remodeler, I felt up to the challenge.
Avoiding re-dos and safety issues
We planned each phase of this virtual gut rehab to keep the place healthy (during and after the work), to be as efficient as possible, and to prepare for future steps. This meant managing a radonColorless, odorless, short-lived radioactive gas that can seep into homes and result in lung cancer risk. Radon and its decay products emit cancer-causing alpha, beta, and gamma particles. problem that worsened as the house was tightened up, monitoring drainage issues around the building perimeter, and adding spot and whole-house mechanical ventilation as phases of the project progressed. Integrating mechanical, electrical, and plumbing work was tricky because we tackled the basement, attic, and individual rooms one at a time.
Phase 1: Storm windows, wiring, and bathrooms
The existing windows were leaky, uncomfortable, and energy inefficient. New triple-track, low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor. storm windows from Harvey Industries gave us nearly instant improvement on all three of those fronts and reduced traffic noise as well. Eight years later, the enameled-frame storms still operate as if they were brand-new.
We rewired the whole house before insulating or air sealing and kept penetrations in exterior walls to a minimum. Because interior walls weren't all affected at the same time, we had to consider how subsequent phases would line up and wire accordingly.
Both bathrooms had exterior walls that needed attention. We wanted to use insulating sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. on the outside, and we found that adding interior plywood sheathing gave us the access and shear strength we needed to do the job right.
Phase 2: Attic, then basement
Particularly in cold climates, stack effectAlso referred to as the chimney effect, this is one of three primary forces that drives air leakage in buildings. When warm air is in a column (such as a building), its buoyancy pulls colder air in low in buildings as the buoyant air exerts pressure to escape out the top. The pressure of stack effect is proportional to the height of the column of air and the temperature difference between the air in the column and ambient air. Stack effect is much stronger in cold climates during the heating season than in hot climates during the cooling season. can drive basement moisture and soil gases up into the living area. Air-sealing and insulating the attic before tackling the basement is almost always the best way to deal with this. With the wiring done and the new bath exhaust fan in, we had a relatively easy time sealing attic penetrations before criss-cross layers of cotton batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. went down.
After a full year of moisture monitoring and simple observation, we found that the basement walls were just a bit damp after the hardest spring rains, but we never saw any liquid water. This gave us confidence that 2x3 studs and vapor-permeable open-cell spray-foam insulation should be a safe way to to air-seal the basement and bring the whole-wall R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. up to about R-12.
Unfortunately, radon readings spiked from 6 pCi/LAbbreviated pCi/L, this term refers to the relative radioactivity contributed by radon gas to one liter (1,000 cc's) of air. A picocurie is one-millionth of a curie and represents about 2 radioactive particle disintegrations per minute. EPA has established an action limit (the level at which some form of radon mitigation should take place) of 4 pCi/L. (already 2 over the EPA action limit of 4 pCi/L) to 12 pCi/L in this now tighter space. In response, we sealed off and insulated the vented crawl space under the front porch (paving the way for the front porch to become a home office), removed a concrete block to have the crawl communicate with the basement, and added a 24/7 high-efficiency exhaust fan. While this didn't lower the radon readings in the basement, the continuous exhaust ensures that radon readings in the first-floor living space are consistently 2.5 pCi/L or less.
Phase 3: SIPS kitchen addition and second-floor bedrooms
A 6x20 addition where roof, walls, and floor are all structural insulated structural insulated panels (SIPs) on piers gave us two things: a weather-tight addition in one long day; and a ready-made, weatherproof mudroom just off the kitchen addition.
Because the shed roof for the addition came right up against the west-facing second-floor bedroom, we moved to this space next. We gutted, resheathed, insulated, air-sealed, and re-sided the room. As we gutted each bedroom, we pulled the gambrelThis is a gable roof with two pitches, the bottom pitch being steeper than the top. The term gambrel is also used to describe the hing leg of a horse, with a angle at the joint that looks like a gambrel roof, or much more likely, the other way around. kneewall spaces into conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. for a continuous air and thermal barrier along the more steeply pitched gambrel roofline. This improved energy performance and added about 1/3 more floor space (albeit with sloped ceilings) to each bedroom.
Phase 4: First-floor exterior walls
Because the concrete-block walls were ungrouted, uninsulated and have many step-cracks, we needed to pull them completely inside or keep them completely outside of the air- and thermal-barrier lines. Chris and I weren't thrilled with the look of the split-faced block, so it was an easy decision to go with the much easier approach of insulating, air-sealing, and re-siding the exterior. A custom system of 2x2s bolted to angle brackets screwed into mortar joints created a space for three inches of high-density spray-foam insulation plus an air space. The surface of the foam now serves as a drainage planePath that water would take over the building envelope. Concealed drainage-plane materials, such as building paper or housewrap, are designed to shed water that penetrates the building’s cladding. Drainage planes are installed to overlap in shingle fashion (weatherlap) so that water flows downward and away from the building envelope., and finger-jointed, preprimed cedar lap siding covers it all up. A 10-in. shed roof bridges the transition between the second-floor walls and the now-thicker first-floor walls.
Along the way: sash weight pockets and HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building.
As we renovated each room, we pulled out the old single-pane windows and installed double-pane replacement sashes. Before everything was closed up, we insulated and air-sealed the often-overlooked but very important sash weight pockets.
We replaced the aging 75% AFUEAnnual Fuel Utilization Efficiency. Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment. forced-air furnace with an 88% AFUE boiler. This allowed us to add a 40-gallon superinsulated indirect water heaterWater heater that draws heat from a boiler used for space heating; a separate zone from the boiler heats potable water in a separate, insulated tank via a water-to-water heat exchanger. See tankless coil. and hydronic heating in the kitchen and downstairs bath/laundry. Because we decided to stick with fuel oil, the new boiler had to be atmospherically vented (there are no sealed-combustion residential fuel-oil boilers). This means that the 24/7 exhaust ventilation/radon mitigation fan had to be dialed in to avoid back-drafting the boiler.
Eight years later: improved comfort, IAQIndoor air quality. Healthfulness of an interior environment; IAQ is affected by such factors as moisture and mold, emissions of volatile organic compounds from paints and finishes, formaldehyde emissions from cabinets, and ventilation effectiveness., and utility bills
Patience, planning and eight years of "working vacations" gave us a home that is markedly more comfortable and has better indoor air quality and lower utility bills than when we bought it. It looks better, works better, and has more living space to boot.
We feel pretty fortunate. The problems with the original house kept it on the market for a long time and meant a really good purchase price for us. And the money we put into performance upgrades brought the cost pretty close to market value of any old house in our area.
We confronted many challenges and learned quite a few lessons along the way. The replacement sashes didn't work well with our out-of-square jambs, so more than a few windows are still leaky where they don't make continuous contact along the sill. The SIPs kitchen floor is just as high performance as the roof, but in the middle of winter, walking from the uninsulated floor with basement below versus walking on the SIPs floor is quite a shock; more insulation is needed to offset the floor being on piers over outside air.
Perhaps the biggest disappointment is in the air-tightness of the home. Despite careful planning of the overlaps of insulation and air-sealing systems, there is still a lot of untraced air leakage. Continuous pathways in the ungrouted block walls and tricky details at the four gambrel valleys are the likely culprits - more-targeted blower door testing should give us a better idea. As with most old homes, this will always be a work in progress.
Peter Yost is director of residential services for BuildingGreen, LLC
- Daniel Morrison
- Peter Yost
- Steve Baczek