My runs around Capitol Hill take me through Seattle’s single-family residential neighborhoods. On almost every block I pass there is at least one home being torn down and rebuilt. It’s an indicator of Seattle’s soaring real estate market. Prices have risen to where it is profitable to buy a home that is “underbuilt” on its lot, tear it down, and build a bigger and newer one in its place. As an aspiring developer, I appreciate the economic forces that drive entrepreneurs to build to the parcel’s “highest and best use.” As an architect, I am eager to see more modern construction in these neighborhoods, and think the mix of old and new enriches the streetscape. But I also recognize that mountains of waste are created and carted to landfills when a home is scrapped.
On one recent run, just west of the arboretum, I saw a new type of rebuild. A modest house had been lifted in place, and a new ground-floor level was being inserted below. This seemed not only ingenious, but also resourceful. Why throw away a perfectly good home if it was simply smaller than the market and zoning codes would allow it to be?
Although they may take issue with the increased height, it seems less likely that neighbors would complain if an existing home is simply raised. The character and aesthetics are largely preserved, albeit in different proportions.
Buckminister Fuller, a proponent of lightweight structures, would ask, “how much does your building weigh?” In the case of the typical American home, the answer would be, “not very much.” A virtue of timber-frame construction, which is ubiquitous throughout the US, is that it is both relatively lightweight and structurally stable. Unlike a brick home, for instance, it is possible to mechanically lift a “balloon-frame” building and relocate it without it crumbling or cracking.
Instead of using balloons, like in the animated film “Up”, pneumatic jacks are positioned under the home to slowly raise it. It’s hardly a trivial undertaking. A structural engineer is required to ensure loads during and after the lift do not jeopardize the home’s integrity. A specialist contractor with experience lifting buildings must be used. All this entails additional cost. However, the increase in value of the home after it is raised and rehabbed is apparently more than enough to offset these costs, as well as the original purchase price and a residual profit for the developer and her investors.
The preponderance of small single-family homes throughout Seattle is at the root of the city’s housing affordability crisis. Local residents are vocal in their opposition to up-zoning proposals that entail increasing building-height limits in these residential neighborhoods. Simply raising those existing homes might be a way of stealthily achieving planner’s aims.
Increasing the floor areas would accommodate larger households. Those newly inserted levels would increase the overall floor area in the market, helping to reduce the prices on a per-square-foot basis. But lifting more homes won’t increase the number of housing units, unless the city allowed the new levels to be entitled as duplexes or so-called mother-in-law units, similar to how it currently supports accessory dwelling units.
Building reuse is an important concept in green building practices. The lift strategy I’ve described could be used to achieve LEED credits in the Materials and Resources (MR) credit category which seek to minimize “the embodied energy and other impacts associated with the extraction, processing, transport, maintenance, and disposal of building materials.” Next to source reduction, material reuse is the next most effective strategy in reducing material waste. (40% of total solid waste in the US is generated by construction and demolition.) More specifically, the lift strategy could be used to achieve between two to four Building life-cycle impact reduction credits which require a minimum of 25% of completed project surface area is reused.
Solving the city’s housing affordability problem requires numerous market-driven solutions. Recycling smaller homes by raising them is one ingenious option to consider, and it also might be the most palatable to local residents too.