Do I need a permit for a full bathroom remodel in
Kenmore, Washington?

Kenmore bathroom remodels — the key details

Kenmore, like all Washington cities, follows the 2021 Washington State Building Code, which is model-identical to the International Building Code. The city's Building Department does not maintain a separate local bathroom code — instead, they apply state code consistently across cosmetic and alteration projects. The threshold for a permit is any work that modifies a plumbing, electrical, or structural system. Per state code (RCW 19.27), a cosmetic-only bathroom refresh (new vanity, paint, tile on existing surfaces, light-fixture swap in existing box) requires no permit. But the moment you move a toilet, sink, or tub — or add a new exhaust fan duct, or install a GFCI outlet in a new location — you cross into the alteration category, and a permit is required. The city's online portal has a simple intake form; you'll answer those five calculator questions, and the system will auto-flag whether you need the full alteration track. Once flagged, you'll need to submit architectural or mechanical drawings showing fixture locations, drain lines, and vent sizing. Kenmore's review time averages 10–15 business days for a straightforward bathroom remodel with no structural issues.

Waterproofing is the most common rejection in Kenmore bathroom permits, particularly for tub-to-shower conversions. Washington State Code (and Kenmore's adoption of it) requires that any shower or tub enclosure meet the waterproofing standard in IRC R702.4.2: a minimum of 6-mil plastic sheeting or a sealed cement-board-plus-membrane system behind all surfaces that contact water. The code allows either liquid-applied membranes (like Schluter or Kerdi) or traditional felt-paper-and-mortar systems, but you must specify which one on your plan before you submit. Kenmore Building Department reviewers reject nearly 20% of initial submissions because the applicant didn't specify the waterproofing system — they'll write 'install standard waterproofing' without saying what 'standard' means. The fix is simple: state on your plan 'Schluter Kerdi waterproofing system, 6-mil minimum' or 'cement board with 20-mil PVC membrane,' and the plan will pass review. If you're converting a tub to a shower or vice versa, the waterproofing detail becomes mandatory because the water-contact surface changes. If you're simply refurbishing an existing shower or tub in place, waterproofing is still required, but if it's currently compliant and you're not opening walls, you may not need to re-detail it on your permit plan (this is a gray area; clarify with the permit reviewer before submitting).

Exhaust ventilation is the second-most-common rejection. IRC M1505 requires a bathroom exhaust fan with a minimum of 50 cubic feet per minute (CFM) for a standard bathroom, or 100 CFM if the fan is integral to the showering space. The duct must terminate outside the building — Kenmore reviewers will reject any plan that shows the duct exhausting into the attic or soffit. The duct must be insulated if it runs through an unconditioned space (like an attic), and it cannot have a return-air path to the home. Kenmore's climate (west-side average winter temps around 40–50°F, east-side 30–40°F) means most bathrooms have adequate airflow, but the duct termination is the sticky point: if your contractor runs the duct to the roof, the exit must have a roof-mounted damper that opens when the fan runs and closes when it's off. If run to the soffit, it needs a comparable damper. Many contractors fail to detail this on plans, and Kenmore rejects them. Once your plan shows an insulated duct with a named damper product (e.g., 'Honeywell spring-return damper model HED-4C'), it passes review.

Electrical work in bathrooms is heavily regulated, and Kenmore enforces NEC (National Electrical Code) requirements strictly. Any outlet within 6 feet of a sink or tub must be GFCI-protected — this is non-negotiable. If you're adding a new circuit to power a heated floor or an exhaust fan, you must show the circuit on a one-line electrical diagram with breaker size, wire gauge, and protection type. Kenmore will not permit an unlabeled electrical plan. Additionally, any outlet within the bathroom must be on a 20-amp GFCI breaker (not a 15-amp), and if the bathroom shares a circuit with other rooms, the whole circuit must be GFCI. If you're swapping a light fixture in place, that's cosmetic and doesn't require electrical permitting. But if you're adding a new exhaust fan with a damper, installing a heated-floor thermostat, or running a new vanity light above the sink, you'll need to call out the work on an electrical plan. Most homeowners in Kenmore use a licensed electrician who pulls the permit themselves (electricians often bundle this into the labor cost); if you're doing owner-builder electrical work, you'll need to submit the plan yourself and request an electrical rough inspection before drywall closes.

Lead paint and pre-1978 bathrooms are a Kenmore-specific compliance issue. Washington State law (RCW 59.18.200) requires that any pre-1978 home undergoing interior renovations must include a lead-paint disclosure and, in many cases, testing or safe abatement certification. Kenmore Building Department does not enforce lead rules directly — that's a tenant-rights and real-estate issue — but it affects your project timeline and cost. If your Kenmore home was built before 1978, assume you'll need to hire a lead-certified contractor for any work involving surface disturbance (sanding, demolition, cutting drywall). This can add $500–$1,500 to a bathroom remodel. Kenmore permit forms now include a lead-paint checkboxon the intake; answering 'yes' means the permit office will note it in your file, but compliance is your responsibility. If you're an owner-occupant (and Kenmore does allow owner-builder work for owner-occupied homes), you're exempt from the lead abatement requirement for your own home, but you still must disclose the issue if you later sell. Don't skip this — it can crater your project schedule if discovered during final inspection.

Three Kenmore bathroom remodel (full) scenarios

Waterproofing details: why Kenmore reviewers reject nearly 1 in 5 bathroom plans

Waterproofing is the single most litigated item in bathroom permits across Washington State, and Kenmore is no exception. The Washington State Building Code, which Kenmore adopts verbatim, references IRC R702.4.2, which requires that any shower or tub enclosure have a water-resistant barrier behind all surfaces that are subject to water spray or saturation. The code allows two methods: a sealed liquid-applied membrane (like Schluter Kerdi, RedGard, or Aqua Defense) or a traditional felt-paper-and-mortar assembly with a cleavage membrane. The reason Kenmore reviewers reject plans is that applicants often write 'install waterproofing per code' without specifying which method. Kenmore staff then has to send the plan back with a request for clarification, which adds 1–2 weeks to the review cycle.

The solution is simple: on your bathroom plan (drawn at 1/4-inch scale or larger), add a note in the tub/shower area that says: 'Waterproofing: Schluter Kerdi or equivalent; 6-mil minimum; installed over cement board, entire shower surround and floor.' If you're using a liquid-applied product, specify the brand and thickness (typically 40–60 mils). If you're using a traditional felt-paper system, specify '20-mil PVC cleavage membrane over felt paper, all seams sealed with compatible sealant.' This detail takes 30 seconds to add and saves you 1–2 weeks in review time. Kenmore staff have also published a short FAQ on their website noting that Kerdi is the single most commonly approved product, so if you're unsure, go with that.

Cost difference between methods is minimal: Kerdi runs $8–$12 per square foot installed; traditional felt-paper-and-mortar runs $6–$10 per square foot. A typical 60–80-square-foot shower surround is $500–$800 in materials. If you're converting a tub to shower or building a new shower, budget for waterproofing cost upfront — don't treat it as a surprise. If you're just rehabbing an existing shower and the old waterproofing is still intact, Kenmore may allow you to leave it in place without opening walls, but clarify this with the permit reviewer in writing before you submit your plan.

Exhaust fan ductwork: Kenmore's attic and roof termination requirements

Kenmore's climate — mild and damp on the west side (average humidity 60–80% year-round), cooler and slightly drier on the east side — makes exhaust fan ductwork critical. The Washington State Building Code requires that all bathroom exhaust fans terminate outside the building envelope, with no return-air path. Per IRC M1505, a standard bathroom needs a 50-CFM exhaust fan; a bathroom with a shower requires 100 CFM. The duct must be rigid (aluminum or metal; flexible vinyl ducts are not permitted by Kenmore code, unlike some other jurisdictions) and must be insulated if it runs through an unconditioned space like an attic.

Kenmore reviewers pay close attention to duct termination: the duct cannot exhaust into the attic, soffit, or crawlspace — it must exit the building through a wall vent, roof vent, or dryer-vent-style fitting on the exterior. If the duct terminates through the roof, it must have a roof-mounted damper (a spring-return or motorized damper that opens when the fan runs and closes when it's off). Kenmore will reject any plan that shows 'exhaust to roof' without specifying a damper product. Common approvals include the Honeywell HED-4C spring-return damper or the Master Flow motorized damper. Cost for a damper is $30–$80; labor for installation is $100–$200. If you're running the duct through the attic, insulation is required — typically 1-inch foam wrap, $0.50–$1 per linear foot.

Duct sizing is also critical: a 50-CFM fan needs a minimum 3-inch duct; a 100-CFM fan needs 4-inch. Kenmore will not approve undersized ducts. Additionally, duct runs should be as straight as possible (each 90-degree elbow adds effective resistance and reduces CFM); if the duct must make turns, they should be 45-degree bends if possible. On your plan, show the duct routing, diameter, insulation type, and damper product. This takes 5 minutes to sketch and can save you 1–2 weeks in review.

Common questions