Additions and alterations to an existing home vary widely in scope. Depending on how extensive the project, you may be able to process your permit as a “Subject to Field Inspection” (STFI) permit. STFI permits need only limited review, have quick turnaround times, and cost less than full Plan Review permits.

Examples of types of projects that typically can be processed as a STFI permit:

  • Roof repair
  • Foundation repair if the foundation is not designed as a retaining wall
  • Demolition
  • Ground-level additions up to 750 square feet, with a limited structural beam span
  • Structural alterations to an existing house under certain limits
  • Detached structures less than 750 square feet with a limited structural beam span
  • Certain dormer additions

If your addition/alteration fits within the scope of a STFI, review our STFI web page for more information on that process. If you'll need a Plan Review Permit, see below. Please note: Construction applications for additions and alterations to existing structures do not qualify for the drop-off submittal process.

Plan Review
Typically, additions and alterations must go through DPD's normal plan review process. DPD offers Client Assistance Memos (CAMs) and forms to help applicants and the design professionals they're working with through the process. Below is a list of information that pertains to this type of permit, as well as a list of forms that should be filled out/finished before each applicant arrives at DPD for their intake appointment.

Helpful Information
The following CAMs provide more information on additions and alterations:

  • CAM 220, Lot Coverage, Height and Yard Standards for Homes in Single Family Zones
  • CAM 303, Applicant Responsibilities and Plan Requirements for Single Family and Two Dwelling Units
  • CAM 303A, Common Seattle Residential Code Requirements
  • CAM 316, Subject-to-Field-Inspection Permits