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REF_07 / CONSTRUCTION

Egress

Also known as: Egress window · IRC R310

The code-required escape opening from every sleeping room — minimum 5.7 sq ft clear opening.

DEFINITION

Egress refers to the code-mandated escape route from every sleeping room in a dwelling. Under IRC R310, every bedroom must have a window or door opening directly to the exterior with a minimum 5.7 sq ft clear opening, max sill height of 44 in, and a minimum 20 in width and 24 in height. Basement AADUs almost always need egress window wells excavated and waterproofed — a $4K–$9K line item that catches many homeowners off-guard.

FAQ

Frequently asked

  • What does Egress mean in the context of an ADU?

    Egress is part of the regulatory and technical vocabulary you encounter when permitting and building an accessory dwelling unit in Washington. Knowing the term matters because reviewers, inspectors, and your lender will use it without explanation. We define Egress in plain English and connect it to the specific code citation, fee, or construction detail that affects your project. Use the related-terms section to navigate adjacent concepts you'll need on the same plan set.

    Go deeper: Glossary: ADU (Accessory Dwelling Unit)

  • Where does Egress apply in the WA ADU process?

    Egress typically shows up in either the design phase (when the architect or designer is laying out plans against zoning), the permit phase (when reviewers check the submittal against code), or the construction phase (when inspectors verify built conditions match the approved set). The same term can appear in your loan documents if it affects valuation or risk. Each glossary entry maps the term to the exact phase where it matters most.

    Go deeper: Read the Puget Sound ADU timeline guide: kickoff to keys guide

  • Why should I care about Egress for my project?

    Misunderstanding Egress is one of the most common reasons ADU projects hit avoidable cost overruns or permit delays. A clear shared vocabulary between you, your designer, and your builder shortens decision time and reduces change orders. Bookmark this glossary and refer back as you progress from feasibility through final inspection.

    Go deeper: Glossary: Egress

  • How does Egress affect my ADU budget?

    Most glossary terms map to either a cost line, a review timeline, or a permit fee. Where Egress drives cost, the impact is itemized in our standard fee schedule and itemized at feasibility — so by contract time, Egress is a known number, not a discovered surprise. Click through to the related cost or permit page for the current Egress-specific dollar range and timeline.

    Go deeper: Read the Five hidden ADU costs that wreck Puget Sound budgets guide

  • Is Egress regulated under RCW 36.70A.681?

    WA statewide ADU preemption (RCW 36.70A.681 / HB 1337) covers many ADU-adjacent topics: size caps, setbacks, owner-occupancy, parking, height, lot-size minimums. Whether Egress falls under preemption depends on its specific scope — design review, side-sewer permitting, drainage review, and tree-protection rules are generally NOT preempted, while size/setback/parking generally ARE. Each glossary entry flags the preemption status.

    Go deeper: Read: Bellevue ADU rules — what changed under HB 1337

TERM_EGRESS

Need "Egress" explained for YOUR lot? Get it in plain English.

Definitions help. Applying them to your specific property is what matters. Send the address and we'll explain how Egress plays out on your build.

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