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, ≤ 30 inches above grade (within 36" horizontally), freestanding (not attached to house ledger), and not serving the required exit door—OR cosmetic re-decking on sound framing.
≤ 200 sq ft, ≤ 30 inches above grade (within 36" horizontally), freestanding (not attached to house ledger), and not serving the required exit door—OR cosmetic re-decking on sound framing.
Local Setback & Municipal Note (City of Castle Rock):
5 ft side setback, 15 ft rear setback; deck board & railing replacement on sound framing needs no building permit.
⚠️ 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. Do I need a permit to replace rotted deck boards in Castle Rock, WA?
No. Cosmetic re-decking—replacing worn timber or composite deck boards and railings on existing sound, code-compliant joists without changing structural footings or ledger framing—does not require a building permit in City of Castle Rock.
2. What is the maximum deck size without a permit in Castle Rock, WA?
Under WA IRC R105.2 adopted by City of Castle Rock, a deck up to 200 sq ft that is no more than 30 inches above grade at any point within 36 inches horizontally, is detached from the house, and does not serve the required exit door is exempt from a building permit.