Small Residential Additions and Remodels

Small Residential Additions and Remodels include:

  • Small Additions that do not alter a critical area or buffer and result in:
    • Less than 500 square feet of new/expanded building footprint
    • Less than 500 square feet of new impervious surface
  • Remodels which affect <40% of the existing exterior wall
  • Upper level additions with a valuation less than $100,000
  • Projects that do not trigger Stormwater Permit Review

If your project meets the criteria above, an Intake Screening is not required. If you prefer to have your submittal screened by a representative from each review discipline prior to intake, you can set up an Intake Screening. 

An Intake Screening is a completeness check conducted by all staff who will be involved in the plan review process. This is an opportunity to find out if there is anything significant missing from your submittal and to identify issues that may cause a delay in the processing of the application.

Prepare:

Pre-Application Meetings are recommended in the early stages of your plan development process. They are an opportunity to meet with a representative from each of our five review disciplines to gain a better understanding of code requirements that can influence the design of your project. Understanding the City’s residential development standards, stormwater, tree protection, and fire access requirements early on can avoid costly re-design delays later in the project.

Required Forms

  1. Building Permit Application
  2. Single Family Plan Coversheet
  3. Site Development Worksheet
  4. Water Meter Sizing Worksheet
  5. Fire Area and Valuation Form
  6. Tree Inventory and Replacement Submittal Information Form 

    Optional Forms

    1. Intake Screening Form
    2. Owner as Contractor (only required if you are a homeowner acting as your own contractor)
    3. Concurrent Review (only required if you are requesting concurrent review of a Land Use action)

Required Documents

Construction Documents - The following items should be merged into a single PDF file for submittal. This package will become your approved drawings set.  Please bookmark each sheet in the plan set (i.e.: A1.1- Site Plan) prior to submittal.  Click here to read our tip sheet on How to Bookmark Plans.

  1. Site Plan
  2. Topographic Survey 
  3. Foundation Plans
  4. Floor Plans
  5. Structural Framing Plans
  6. Cross Sections
  7. Elevations
  8. Tree Plan- see the Tree Submittal Checklist for more details.  Click here for more information about Trees & Construction.

Additional details as necessary for the construction of the proposed scope.

Supplemental Documents - The following, if applicable to the project, should be uploaded as separate clearly named files. These documents support the design proposed in the Construction Documents and will be reviewed concurrently.

  1. Geotechnical Report - if work is proposed in a geohazard area
  2. Critical Area Study - if work is proposed in a critical area
  3. Energy Code Worksheet
  4. Structural Calculations
  5. Stormwater Report - if Stormwater Permit Review is required 
  6. Arborist Report - if removing or working within the drip line of one or more trees
  7. Utility Plan 
  8. Addition details as necessary for the construction of the proposed scope

How to Apply

Submit your plans, forms, and supplemental documents to the Mercer Island Permit Submittal Portal.  

If an Intake Screening has been requested, staff will schedule the Intake Screening, and will email you the screening results.

  1. If the submittal is incomplete, the results will include instructions to address staff comments and resubmit.
  2. If the submittal is complete, it will then be routed for review.

Required Reviews

  • Land Use Planning
  • Building
  • Civil Engineering
  • Tree
  • Fire

Related Applications

Complete submittals for applications related to the Building Permit should be uploaded to the Mercer Island File Transfer site in separate folders. Include all documents required for submittal in the folder.

  1. Accessory Dwelling Unit - Required if project includes a new Accessory Dwelling Unit
    1. Accessory Dwelling Unit Submittal Requirements
    2. Accessory Dwelling Unit Affidavit
    3. Development Application
  2. Seasonal Development Limitation Waiver - Required if land clearing, grading, filling, or foundation work will occur between October 1 and April 1 on sites located in Erosion, Potential Slide, or Steep Slope Hazard Areas.
    1. Seasonal Development Limitation Waiver
    2. Development Application
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