Meets Base WA IRC R105.2 Dimensional Exemption (Subject to Local Setbacks & Site Overlays)
City of Castle Rock Base WA IRC R105.2 Dimensional Rule:
≤ 200 sq ft floor area, single-story, detached residential storage/tool shed with no plumbing or habitable sleeping space (must still obey local 5 ft property line setbacks).
≤ 200 sq ft floor area, single-story, detached residential storage/tool shed with no plumbing or habitable sleeping space (must still obey local 5 ft property line setbacks).
Local Setback & Municipal Note (City of Castle Rock):
≤ 200 sq ft detached residential shed exempt from building permit; must meet 5 ft side/rear property line setback.
⚠️ Informational Code Reference Only — Not an Official City Determination: Even when a deck, wall, shed, or fence meets the base WA IRC R105.2 dimensional threshold, local property-line setbacks, critical-area/wetland buffers, shoreline overlays (e.g., Kalama/Columbia/Lewis rivers), steep-slope geohazard zones, utility easements, separate electrical/plumbing permits, and HOA rules still apply. The property owner and contractor of record are solely responsible for verifying parcel rules with the local permit counter before work begins.
Frequently Asked Questions (Castle Rock, WA)
1. Can I build a 10x20 (200 sq ft) shed without a permit in Castle Rock, WA?
Yes. Under WA IRC R105.2 as enforced by City of Castle Rock, a one-story detached residential storage shed with a projected roof/floor area of 200 sq ft or less (such as a 10x20 or 12x16 shed) is exempt from a building permit, provided you obey property line setbacks.
2. Do permit-exempt sheds still have to follow setbacks in Castle Rock, WA?
Yes! Even when a shed under 200 sq ft is exempt from a building permit, City of Castle Rock zoning still requires keeping it out of utility easements and maintaining the required side and rear yard setback (typically 5 feet).