Deep Energy Retrofit

This project was brought to me as a foreclosure sale. The woman who built the house in the 1970s lived there until she died. In her later years, apparently a flock of birds, and hundreds of pounds of dogs had run of the place. Before my clients took possession it had been fumigated. The former bird room had been partially torn out to remove built-up degradation indoor livestock had brought on. even after we began in mid March, the crews working would acquire ticks, and find mouse nests full of bird seed. That bit wasn't over until we were down to studs and we fumigated again. (fun!)

The homeowners wanted to bring the 70s child up to a Modern aesthetic. Without too much similar housing in Vermont, they partnered with Architecht Missa Aloisi out of Burlington to come up with one stunner of a design.

A Deep Energy Retrofit is a new(ish) concept in remodeling. Deep refers to the level of rip-out and rebuild. Energy consumption is the focus both in how much is used and how long a home can stay good before needing to consume more energy. Retrofit just means that it is done on existing housing stock, not new builds. Much of this stuff should be common on new construction (though some is rarely seen).

In Vermont, though outside of Burlington we see no inspectors, once you impact more than a certain amount of a home, you are not repairing anymore, and your work must be brought up to current Vermont Residential Building Energy Standards (based on the IEC2009, 2015). It is handy in that many building styles and shapes from SIPs to metal and stick framing is covered in prescriptive detail. My clients wanted to beat the code requirements wherever possible, while still adding windows and keeping the home healthy.

Code asked for a R-20 wall, which is difficult in a 2x4 house. When we finally got done supporting the nearly 35' clear span trusses across a bank of 6'wide windows, it didn't leave any cavity left in the walls between windows for insulation. Worried about thermal bridging across those little 2x4s, we opted to wrap the entire house in a layer of 2" blue board rigid foam insulation. I chose this product because it could be used continuously from the footer on the foundation to the soffits without worry of water damage over time. We were already replacing a damaged drain at the footer, and cutting in two beautiful egress windows through the foundation, so it made sense to keep the primary thermal envelope continuous. We taped the rigid foam edges with Zip Tape to further use it as the primary air barrier too. The foam was screwed to the studs with 4" screws through vertical strapping, which later we stapled the prefinished wood siding to. That left a 3/4" gap behind most of the siding for a rain screen effect. The siding manufacturer (Jus Du Pin out of QC, Canada) provided a wonderful stainless steel starter strip with vent holes to prevent bug intrusion behind the rain screen, but we backed it up with aluminum window screen material too.

The attic saw extensive air sealing around the indulgent collection of pot lights (recessed cans). I usually don't like to put them in ceilings with cold air above because they tend to turn into little illuminated chimneys for convection heat to escape through. we then added ductwork for exhaust fans and blew in a 18" blanket of cellulose over the remnants of the original double layer fiberglass. The end result read r70 when fluffy, but that should settle to about r60ish in a little while. Plenty even in a climate which could see a Difference in Temperature of more than 100 degrees across a wall or window.

The tight thermal and air envelopes meant that our heating demands would change. That was not a problem, since the house previously relied on electric baseboard heat and a couple of large wood stoves. A new high efficiency condensing boiler would now serve the upstairs radiant heat and the lower level baseboards, with a take-off for domestic hot water. Since we changed the window and door openings nearly every wall, the electrics were in tatters and needed to be upgraded. New features were added because we changed the location of the kitchen from one corner of the house to another.

The Modern aesthetic came out in the interior with full sheetrock returns on every window and exterior door. Simple trim and a glue-down Maple engineered flooring kept it simple and classy. We echoed the Maple in trim details such as the back of the kitchen Island and a set of shelves on the old chimney. We used locally sourced 8/4 wood straight from a sawmill in Bristol, VT. Outside the use of Metal wrapped black trim and the giant black I-Beam porch give the home an almost industrial appeal, yet with the peaked roof, and covered porches, it remains cozy and inviting.
 

Time Scale    March through August 2015                                                      Total Project Cost   $155k







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