Codes, Design Criteria & Research

2018 CODE - [February 1, 2021 - March 14, 2023]

Effective February 1, 2021 Washington statutes mandated all jurisdictions in the state adopt and enforce the following updated Construction Code editions as they were adopted and amended by the State of Washington:

2018 Code Cycle
2018	International Building Code (IBC)
2018	International Residential Code (IRC)
2018	International Mechanical Code (IMC)
2018	International Fuel Gas Code (IFGC)
2018	Uniform Plumbing Code (UPC)
2018	International Fire Code (IFC)
2018	International Existing Building Code
2018	International Swimming Pool and Spa Code
.	Washington State Energy Code (WCEC)
.	ICC/ANSI A117.1-09, Accessible and Usable Buildings and Facilities, with statewide and City amendments

_{***Permit applications received on or after February 1, 2021 shall comply with these codes.***}

Significant Code Changes

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** Click here to see a listing of significant code changes made in 2018. **

Washington State Amendments to the 2018 Construction Codes

Click here to see Washington State amendments to the 2018 Construction Codes.

City Amendments to the 2018 Construction Codes: the local amendments in the Mercer Island City Code including items such as:

When fire sprinklers are required (for new and substantially altered single-family dwellings, larger buildings, poor water supply, poor fire access roads, etc.)
Administrative provisions (when permits are required, permit expiration and renewal, etc.)
Electrical code amendments
Waterfront Structures
When special inspections are required (exterior insulation finish systems, etc.)
Adopted appendices (fire access roads, etc.)

2018 Design Criteria Table
Click here for information regarding minimum design criteria for snow loads, wind and seismic forces, climatic, geographic, and more.

Wind Exposure and Minimum Kzt Factors
Click here to view the City map depicting Wind Exposure Classification and minimum K_zt factors (topographic effects) that will not require the submittal of justifying engineering calculations.

Geologically Hazardous Area Maps and Regulations: Development within Geologically Hazardous Areas requires supporting Geotechnical Reports.
Maps of Landslide, Seismic, and Erosion Hazard Areas
Wet Season Grading Restriction
Mercer Island City Code 19.07.160 Geologically Hazardous Areas