We've written about "density without demolition". This means adding housing to a neighborhood without tearing down the existing houses.
One way to do this is through accessory dwelling units (ADU). An ADU is a separate, legal housing unit with kitchen, bathroom, and bedroom(s), that is added to an existing house. It can be in the basement or a new detached structure in the backyard. Garages can be converted to ADUs. Sometimes ADUs are built in the main floors of the house, or in an addition to the house.
In Laurelhurst, we have at least 26 ADUs. The 26 ADUs include 13 detached/garage conversions and 10 basement conversions. There are also 2 ADUs in the main house or addition; this sort of ADU is basically a duplex. 1 ADU is of unknown type. This is based on city building permits; there are some older unpermitted ADUs out there too, and about 4 housing units that are not being used as ADUs.
ADUs started to become popular in Portland after 2010, when the city exempted new ADUs from System Development Charges, a fee for new construction that can be as much as $20,000 per unit.
Since 2010, our neighborhood really started to build ADUs. The pace of new ADUs is accelerating. 21 of these 26 ADUs were built since 2010. 12 ADUs have been built since 2015.
As you walk around Laurelhurst, you likely won't notice these ADUs. They fit in so well with the neighborhood. Here are two houses with ADUs.
These are the original Laurelhurst houses, both from 1923. Neither was demolished, and each lot can now be home to two households.
That is "density without demolition" or "gentle density". A historic district will allow Laurelhurst to do our part in adding housing, without being demolished and redeveloped.