Peaks Island, sitting in the Portland, Maine harbor a 20-minute ferry ride from downtown, falls into Portland's municipal jurisdiction. The small island community (about 600 fulltime residents, but swelling in the summertime to host thousands of summer visitors) is served by Portland schools, Portland police, Portland firefighters, and — the important factor for builders — Portland building officials.
The building code on Peaks Island is a recent version of the International Residential Code, and it's enforced. But most of the existing structures on the island were built long before any such code was in place, and have been modified over the years without strict oversight. So contractors who remodel homes on the island routinely face the challenge of bringing an antiquated, primitive, and idiosyncratic building into the 21st century.
This winter, contractor Heather Thompson (Thompson Johnson Woodworks) and her project manager Mark Pollard are tackling a classic example: the structural rehab and deep energy retrofit of a typical island house — a lightly framed structure, with a simple masonry block foundation, no footings, and no insulation. The job was designed by local architect Rachel Conly, with engineering services provided by island engineer Andrew Jackson. JLC's Coastal Connection has been following the project. In December, we reported on the foundation underpinning work. This week, we take a look at the structural rehab of the building's upper story floor system and roof (see Slideshow: Island House Structural Rehab).
Before they're done, Thompson's crew will have transformed the building into a modern air-tight above-code energy-efficient house, with frost-protected footings, a basement insulated to R21, walls insulated to R40 or better, and a roof insulated to about R60. The structure will heat with a miserly pair of air-source mini-split heat pumps. But the crew is a long way from that result — because first, they have to repair the home's egregious structural deficiencies. The main structural challenges are excavating under the unreinforced masonry block walls to place concrete footings; jacking up, straightening, and reinforcing the first floor system (which sagged more than four inches across its 26-foot span); and straightening and reinforcing the complex dormered hip roof of the building.
Along with the extensive structural reinforcement, Pollard and his crew are also packing out the home's walls and framing down its roof to create space for insulation — a complex challenge that calls for meticulous work because of the existing frame's (for lack of a better word) out-of-whackness. For a closer look, see the slideshow.