Verified 2026-05-01
Construction or trade permit check for insulation and air-sealing work
SDCI's permit guidance says most projects in Seattle require a permit, but it lists insulating existing buildings among miscellaneous work that usually does not require a permit unless the project is in an environmentally critical area or another limiting condition applies. The same guidance says a permit is required for work on load-bearing supports, changes to the building envelope, or work that reduces egress, light, ventilation, or fire resistance, so insulation or air-sealing work should be checked when it is bundled with envelope, structural, mechanical, electrical, roofing, or other trade work.
Official application