Green Structures NW
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Guidelines
   
Although each city develops their own guidelines for ADU's, generally the units cannot be more than 75% of the existing homes square footage and cannot exceed 800 SF.  (Salem is 900 SF)  Essentially if your existing home is over 1100 SF, you are limited to the 800 SF maximum.

Units can be detached, stand alone buildings or can be incorporated into an existing structure.  Attached units can be built over a garage, garage conversion, or built on to an existing home.  Typically, the ADU must be its own living unit with no direct access to the main house.

Complete kitchen and bathroom must be part of the plan.  As well as a heating system.  Cooling is optional, but mini-split systems offer both in one compact design that works perfectly with ADU's.  Owners can elect to run power and water off the existing meter or have a separate meters installed. 


Floor plans can range from studio designs to one or two bedrooms.  They must include both a bathroom and kitchen.  Space saving and energy efficient ideas to consider are OnDemand hot water, Radiant Heat, and Mini Split systems.