Building Permits - When are they Required?

COMMENTARY

Each permit type administered by Community Planning and Development will have a threshold for when a permit is required.  The threshold that determines when a building permit is required can be complicated and you are encouraged to reach out to address your specific situation.

It is important to note that exemption from a building permit is not the same as being exempt from building codes, or other codes that may apply to a project.  If a project does not require a building permit, it’s the owners responsibility to research and verify that all aspects of the project meet applicable codes (including the City’s land use codes, which controls the locations, uses, and heights of structures).

If your project does not require a building permit but does involve conventional construction methods, or the requirements for setbacks or structure height in the land use code are difficult to apply to your situation (examples might be children’s playhouses or tree houses and arbors), you can still apply for a building permit to document the scope of work and get department review and approval.

PERMIT REQUIRED / NOT REQUIRED

Construction Administrative Code

The rules that staff use to determine when a building permit is required are found in the Mercer Island City Code (MICC), MICC 17.14.010, along with regulations on permit application, expiration, and renewal.  There are two important sections. 

1. Section 105.1 contains a very broad definition of when a permit is required (and project that intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system). 
2. Section 105.2 then contains enumerated lists of exceptions to each permit.  There are 22 different types of exceptions to building permit requirements including some fences, some above ground swimming pools, some window replacements, and even certain small buildings.

City Land Use Critical Areas

MICC 17.14.010: Most work that occurs in the ground or vegetation in a critical area will require a permit.

Complete definitions for each type of critical area are found in MICC 19.16.010.  The City developed a Geographic Information Systems (GIS) tool that maps potential locations of these hazards and risks that is available on the Online Mapping Portal.  Without the exemptions in Section 105.2 available, most work that touches the ground or vegetation in a critical area will require a permit.

In order to reduce irreversible harm to locations where environmental risks are present, the City Code does not recognize the list of exemptions in these areas.  

"The following permit exemptions shall not apply to Areas of Flood Hazard and City Land Use Critical Areas unless the work is entirely within or on the exterior envelope of a legally established existing building." MICC 17.14.010, Section 105.2

Some permits shall not be required for the following:

• One-story detached accessory structures constructed under the provisions of the IRC used as tool and storage sheds, tree supported play structures, playhouses and similar uses, provided the floor area does not exceed 200 square feet (18.58 m 2 ).
• Fences not over 6 feet (1,829 mm) high.
• Retaining walls and rockeries which are not over 4 feet (1,219 mm) in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids.
• Water tanks supported directly on grade if capacity not exceed 5,000 gallons (18,925 L) and the ratio of height to diameter or width does not exceed 2 to 1.
• Sidewalks, decks and driveways constructed under the provisions of the IRC, which are not more than 30 inches (762 mm) above grade and not over any basement or story below.
• In-kind re-roofing of one- and two-family dwellings provided the roof sheathing is not removed or replaced.
• Painting, non-structural wood and vinyl siding, papering, tiling, carpeting, cabinets, counter tops and similar finish work, provided that existing, required accessible features are not altered. This exemption shall not apply to veneer, stucco or exterior finish and insulation systems (EFIS). This exemption shall not apply to structures regulated under RCW Chapter 64.55.
• Prefabricated swimming pools accessory to one- and two-family dwellings or Group R-3 occupancy which are less than 24 inches (610 mm) deep, do not exceed 5,000 gallons (18,925 L) and are installed entirely above ground.
• Shade cloth structures constructed for garden nursery or agricultural purposes and not including service systems.
• Swings, slides and other similar playground equipment.
• Window awnings supported by an exterior wall which do not project more than 54 inches (1,372 mm) from the exterior wall and do not require additional support of a one- and two-family dwelling or a Group R-3 or U occupancy.
• Decking replacement on decks without changing or adding any other structural members or removing guardrails.
• In-kind window replacement for IRC structures where no alteration of structural members is required, safety glazing is provided where required, window fall protection is provided where required, emergency egress requirements are provided and when the window U-values meet the prescriptive requirements within the Washington State Energy Code.

Retaining Walls - Expanded 

Is a building permit required to build a retaining wall?
As seen above retaining walls can be exempt from permits: "Retaining walls and rockeries which are not over 4 feet (1,219 mm) in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids."

• A building permit is not required for a wall that is: Four (4) feet high or less measured from the bottom of the footing to the top of the wall.
• Located with flat ground on both the upper and lower sides
• Not supporting a surcharge from a driveway or building or another structure such as a fence and:
• Built on private property, unless a Street Occupancy Permit from Real Property Services has been obtained for the wall to be located within the right-of-way.
• Not in a critical area.