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 12×12 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 radon 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-e 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 sheathing 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 effect 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 insulation 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 2×3 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-value up to about R-12. Unfortunately, radon readings spiked from 6 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 6×20 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 gambrel kneewall spaces into conditioned space 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 plane, 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 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% AFUE forced-air furnace with an 88% AFUE boiler. This allowed us to add a 40-gallon superinsulated indirect water heater 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, IAQ, 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.