Seattle Detached Garage Site Plan for Permit: Building Footprint, Vehicle Access and Property Lines
Planning a Detached Garage in Seattle?
Prepare a clear property layout showing your proposed garage, vehicle access and nearby structures. Gather your property records and project dimensions before ordering.
A detached garage needs to fit both the property and the way vehicles will reach it. Before construction, your drawings should explain the building’s size, its relationship to property lines and the route between the garage doors and the street or alley.
A Seattle detached garage site plan for permit should clearly communicate the proposed footprint, vehicle access and surrounding property layout. Seattle’s Tip 103 explains that construction permit applications require site plans and distinguishes basic and enhanced site plan information.[1]
Confirm the required drawing scope with the Seattle Department of Construction and Inspections, or SDCI, before ordering.
Which Permit Does a Seattle Garage Need?
Seattle’s garage guidance identifies a subject-to-field-inspection permit pathway for qualifying garages. Published criteria include a maximum area of 750 square feet, one story, no roof deck, beam spans of 14 feet or less and a property outside an environmentally critical area. Projects that do not qualify use the addition or alteration permit pathway.[2]
Those criteria help identify the review process; they do not establish that a particular garage location or design is allowed.
When contacting SDCI, provide the proposed dimensions, height, roof design, intended use and property address. Clearly explain whether you are replacing an existing garage or adding a new structure.
Show the Proposed Building Footprint
The footprint identifies the garage’s position and size when viewed from above. Label the proposed building and provide its exterior dimensions.
Distinguish between:
- Exterior wall footprint: The outside dimensions of the garage walls.
- Roof projections: Eaves, gutters or other overhangs beyond the walls.
- Driveway or apron: The paved area serving the garage doors.
- Other proposed work: Walkways, stairs or retaining walls associated with the project.
Send the latest building drawings or contractor’s proposal. If different documents show different garage dimensions, resolve that discrepancy before the site plan is finalized.
Make Vehicle Access Easy to Understand
Show how a vehicle will travel from the street or alley to the garage doors. Identify the door location and the driveway or apron serving it.
A directional arrow can explain the route, but the layout also needs enough dimensional information to evaluate access. Include nearby fences, walls and other features that may affect turning.
Seattle’s parking guidance identifies driveway width, slope, maneuvering space, sight triangles and curb cuts as regulated design considerations. It also lists a curb cut permit for creating driveway access from a street.[3]
Confirm the allowed access arrangement for your property before committing to the garage orientation. The presence of an alley does not, by itself, resolve every access requirement.
Check Street and Alley Conditions Early
If your proposal involves a new or changed access point, explain that in the project description. Provide photographs showing the existing street or alley, pavement edges, sidewalk and driveway connection.
Seattle notes that some projects require street, alley or pedestrian improvements. The requirements depend on the project and location and can affect access design or the space reserved beside the right-of-way.[4]
Ask SDCI whether Seattle Department of Transportation review is needed. Confirm those conditions before treating the garage position as final.
Identify Property Lines and Proposed Distances
Supply an existing survey or reliable property records when available. Include boundary dimensions, recorded easements and the complete document notes.
Show the garage’s proposed distances to the relevant property lines and existing buildings. Identify the measurement reference points, including whether a distance is to a wall or roof projection.
Do not assume a fence establishes the legal boundary. If the boundary position is uncertain, ask a licensed land surveyor what verification is needed.
Confirm the current zoning requirements for your address with SDCI. Avoid relying on another property’s garage placement as evidence that the same arrangement is permitted on your lot.
For background, read why accurate property lines matter on a site plan.
Include Existing Structures and Site Features
Show the house, existing garage, sheds and other relevant improvements. Include patios, decks, driveways and walkways where they help explain the proposal.
Clearly distinguish existing features that will remain, proposed work and structures scheduled for removal. If you are replacing a garage, identify the existing and proposed footprints separately.
Also flag trees near the work area, slopes, retaining walls, drainage features and known utilities. Ask the reviewer which additional documentation is needed for these conditions.
Check Environmental and Ground-Disturbance Requirements
Seattle’s garage guidance calls for a pre-application site visit when the project is in an environmentally critical area or excavation exceeds 750 square feet, including associated driveway or paved areas.[2]
Consider the full construction area rather than only the garage floor. Tell SDCI about excavation, driveway work and changes in ground level.
If additional surveying, geotechnical information or grading design is required, confirm who will prepare it before ordering the final drawing package.
What to Send Before Ordering Your Site Plan
| Information | What to Provide |
|---|---|
| Property records | Full address, existing survey and relevant recorded documents. |
| Garage design | Exterior dimensions, height, roof projections and garage door locations. |
| Proposed placement | A marked-up sketch and known distances to boundaries and structures. |
| Vehicle access | Street or alley access route, driveway layout and proposed apron dimensions. |
| Current conditions | Photos showing buildings, access, slopes, trees and nearby improvements. |
| Review instructions | SDCI checklist, preliminary assessment and any written reviewer comments. |
Review the Complete Layout Before Submission
Compare the site plan with the garage construction drawings. Confirm that building dimensions, door orientation, driveway connections and property-line distances agree.
A site plan communicates the property layout. Confirm separately what structural drawings, drainage information, surveys or professional certifications the project requires.
Use our site plan requirements checklist and site plan versus survey guide to organize your information before ordering.
Ready to Prepare Your Seattle Garage Site Plan?
Gather your property records, proposed garage dimensions, vehicle access layout and SDCI instructions so the drawing scope can be matched to your project.