It's happening all over, and wood construction can make it even easier and faster.
After showing The Green House on Cambridge Heath, which included a new floor on top of an existing building, Seattle architect Mike Eliason, who is currently working in Germany, tweeted:
He wrote in The Urbanist a few years ago about how these would be a good idea back in Seattle.
Aufstockung is a German term for a vertical addition. That means an increase in height by the addition of one or more floors to an existing structure. Aufstockungen are quite common in Europe, and have been for generations.
He lists many benefits for allowing them everywhere. Here are some of them:
- It would reduce pressure to tear down older buildings by increasing their income potential. This is especially critical as land values continue to rise, along with corresponding rents.
- It would accommodate additional density.
- It extends the usefulness of the building.
- It preserves the character of the street. I’m constantly shocked at the number of urbanists that find block after block of banal developments acceptable, especially as they consume Seattle’s gritty heritage– heritage that contributes to the vitality of neighborhoods like Capitol Hill. I’m a big fan of granularity, diversity, and keeping something other than a semblance of old facades.
- It can drive (actual) innovation. In many European cities, units or floors are being installed as prefabricated elements, saving substantial time (installation of lightweight wood panels or modules in a few days or less), money – and in some instances, both.
- Sustainability, sustainability, sustainability.
Eliason notes that rooftop additions are not uncommon in North America,"though generally reserved for the wealthy." But recent building code changes may make a difference. In Toronto where I live, there are miles and miles of main streets with two storey buildings. Now that the code allows wood construction to six storeys, many building owners and developers are considering going up with lightweight wood framing.
It is also an opportunity to upgrade the existing buildings; Eliason is "intrigued by pairing this with Passivhaus retrofits. If you’re already ripping off the facade to add new sheathing for the vertical addition, it would also be a smart time to add exterior insulation (mineral wool) and quality windows."
It's time for more Aufstockungen everywhere.