Do I need a permit for a full bathroom remodel in
Allen Park, Michigan?

Allen Park bathroom remodel permits — the key details

Allen Park Building Department issues bathroom remodel permits under Michigan's 2015 International Building Code (IBC) adoption, with local amendments focused on plumbing, electrical, and waterproofing. The single most important rule: any relocation of a plumbing fixture — toilet, sink, shower, or tub — triggers a permit requirement. This includes relocating the drain or supply lines to new stud cavities, moving a toilet to the opposite wall, or installing a new shower where a tub was. You'll also need a permit if you're adding new electrical circuits (like dedicated 20-amp circuits for a heated towel rack or ventilation fan), installing a new exhaust fan or ductwork, converting a tub to a shower (which changes the waterproofing assembly under IRC R702.4.2), or removing/moving interior walls. The reason for this rule is straightforward: fixture relocation affects drainage pitch (which must maintain 1/4-inch drop per foot per IRC P3121), trap-arm length (which is capped at specific distances per IRC P3201), and vent-stack placement — all things that fail if done wrong and cause drainage backups or sewer gas leaks.

Waterproofing is where many Allen Park homeowners stumble. If you're converting a bathtub to a shower or installing a new shower, the entire assembly — the pan, walls, framing, and membrane — must comply with IRC R702.4.2, which requires a mortar bed or preformed pan with a secondary waterproof membrane (typically polyvinyl chloride, vinyl composite, or a cement-board-and-liquid-membrane system). You'll need to specify this system on your permit application and rough-framing inspection. Inspectors here will walk the wall to verify the membrane is properly lapped and sealed before drywall goes up. If you're just re-tiling an existing shower or tub surround and not moving the fixture or changing the pan, you can often skip the permit — but the moment you disturb the framing, membrane, or fixture location, a permit is required. Lead-paint rules also apply in Allen Park if your home predates 1978: any bathroom work that disturbs paint triggers a lead-safe work practices disclosure, and if you hire a contractor, they must be EPA-certified. DIY (owner-builder) work doesn't require lead certification, but you must still provide the disclosure notice.

Electrical work in bathrooms is heavily regulated under the National Electrical Code (NEC), adopted by Michigan. Allen Park requires that all bathroom countertop circuits be 20-amp, dedicated (one circuit per bathroom group or split per NEC 210.52(C)), and protected by GFCI receptacles within 6 feet of a sink. If you're adding a heated towel rack, exhaust fan motor, or ventilation blower, each of those may need its own circuit. If the exhaust fan is within 7 feet 6 inches of a bathtub or shower, it must also have AFCI (arc-fault) protection per NEC 210.12(B). Your electrical plan will need to show the circuit breaker assignment, wire gauge, and GFCI/AFCI device locations. Many homeowners think a GFCI outlet is sufficient; the city wants to see it on the plan and verified during rough electrical inspection before drywall closure.

Exhaust ventilation is governed by IRC M1505 and requires a minimum 50 CFM (cubic feet per minute) for bathrooms under 100 square feet, or 1 CFM per square foot for larger bathrooms. The duct must be hard-piped (not flex duct only) to an exterior termination, sloped at 1/4-inch per foot minimum, with no damper that traps moisture, and terminating at least 12 inches from windows and doors. The most common inspection failure in Allen Park is exhaust duct termination: inspectors verify that the duct actually exits the exterior wall or roof and isn't just dumping into an attic or unconditioned space. If you're adding a new exhaust fan in a bathroom that previously had none, the permit requires showing the duct run on a plan and a final inspection of the termination.

Filing a bathroom remodel permit in Allen Park is straightforward: submit your application (available at city hall or online), include a one-page sketch or floor plan showing fixture locations and wall moves (if any), an electrical one-line diagram or outlet plan showing GFCI/AFCI devices and circuit assignments, and a written description of work scope. If you're relocating plumbing, mark old and new fixture locations. The City of Allen Park Building Department charges permit fees based on the total project valuation: typically $200–$500 for a standard fixture-relocation remodel, $500–$800 if you're adding circuits or doing major wall work. Plan review takes 2-5 weeks depending on whether inspectors request clarifications on waterproofing details or exhaust ductwork routing. Inspections are scheduled in this order: rough plumbing (after fixture lines are run but before walls close), rough electrical (before drywall), then final (after all work is complete and surfaces finished). If you're not moving walls or changing framing, drywall inspection is often skipped. Owner-builders can pull permits for owner-occupied homes; if you hire a contractor, they must carry a Michigan residential builder license.

Three Allen Park bathroom remodel (full) scenarios

Waterproofing assemblies: the Allen Park inspector's focus

Allen Park Building Department issues many bathroom permits, and waterproofing failures are the most common reason for re-inspections and failed final inspections. IRC R702.4.2 requires a secondary waterproof membrane in any shower or tub enclosure, and Michigan's 2015 IBC adoption is strict about this. The two most common systems are: (1) mortar bed (cement-based pan) with a liquid waterproof membrane applied to the framing and substrate before tile (this is the traditional method and preferred by many inspectors in the region), and (2) preformed fiberglass or acrylic pan with a full-wall waterproof membrane installed from the pan lip up to the ceiling. You must choose one system and specify it on your permit application. Don't say 'waterproofed shower' — say 'preformed fiberglass pan (manufacturer name) with 1/2-inch cement board substrate and RedGard liquid membrane' or 'mortar bed with Schluter-KERDI membrane system.' Allen Park inspectors will walk the rough waterproofing before you tile and verify that the membrane is continuous, lapped at seams, and sealed at pipe penetrations.

The reason waterproofing is so critical in Allen Park is climate and soil. Zone 5A south of Eight Mile Road experiences 42-50 inches of annual precipitation and freeze-thaw cycles that can push water into wall cavities if the membrane fails. Glacial-till soil in the area also means older homes often have damp basements, and bathrooms on the first floor or basement are particularly vulnerable. An improperly sealed shower pan or membrane failure will lead to mold, framing rot, and structural damage within 2-3 years. Inspectors here have seen six-figure remediation bills and will not sign off on waterproofing until they see the membrane installed, verified, and documented with photos. If you're hiring a contractor, confirm they've done tub-to-shower conversions in the area and understand the local inspection sequence.

Tile is installed after the final waterproofing inspection. Don't tile before the inspector signs off on the membrane. Many DIY homeowners make this mistake: they seal the walls, assume they're done, and start tiling without a permit or inspection. The moment the grout fails (which it will over time), water penetrates the tile and migrates through the substrate, causing damage that can take years to manifest. Allen Park's inspection process is designed to prevent this: rough waterproofing inspection happens before tile, ensuring the membrane is in place and passes before water-exposed surfaces are sealed.

Cost-wise, a waterproofing system typically runs $800–$2,500 depending on whether you're using a mortar bed or preformed pan and which membrane product you choose. RedGard and Schluter systems are popular in Michigan and widely available. Budget for the inspector's time and possible re-inspection if the first walkthrough finds gaps in the membrane sealing.

Plumbing fixture relocation: drainage pitch, trap arms, and inspection timing

Moving a toilet, sink, or shower drain in an Allen Park bathroom is one of the most code-sensitive changes you can make. The permitting and inspection process exists to verify two critical IRC rules: (1) drainage pitch must be a minimum 1/4-inch drop per foot of pipe length (IRC P3121), and (2) trap-arm length for each fixture is capped at specific distances — typically 6 feet for a toilet, 2.5 feet for a sink, and 3 feet for a tub drain (IRC P3201). Violate these, and you'll have standing water, slow drains, or sewer gas backflow into the bathroom. During rough plumbing inspection, the Allen Park inspector will measure the slope of the new drain lines, verify they're properly supported below the floor or slab, and confirm the trap arm lengths meet code. If you're running a new drain under a slab, the slope and support matter even more in zone 5A because frost heave or settling can break a poorly pitched line.

Trap arms are a common point of confusion. If you're moving a toilet drain from one wall to the opposite side of the bathroom, the new trap arm — the horizontal pipe from the toilet's trap weir to the vent — cannot exceed 6 feet. If you're moving a sink, the trap arm cannot exceed 2.5 feet. Measure twice before you permit. If your layout would require a trap arm longer than allowed, you'll need to install an auxiliary vent or air-admittance valve (AAV) to satisfy code, which adds cost and complexity. An early phone call to the Building Department during design can save you thousands in rework. The frost depth in Allen Park (42 inches) means drain lines below grade must be sloped and vented to prevent ice blockage; if you're moving a drain in winter or in a cold basement, discuss this with the inspector before starting work.

Rough plumbing inspection timing is critical. You must schedule the inspection after the pipe is run and before any concrete is poured, walls are closed, or the slab is patched. If you pour concrete or patch drywall before inspection, the inspector may require you to cut it open for verification, costing $500–$2,000 in remediation. Allen Park's Building Department scheduling is typically 3-5 business days from request, but they recommend calling ahead (especially in winter) to confirm availability. Once the inspection is complete and passed, you can close walls or pour slab. If the inspection fails, the inspector will mark what needs correction, and you'll re-inspect after fixing it (typically 1-2 days turnaround). Build this timeline into your project schedule: rough plumbing inspection happens before rough electrical and framing, so coordinate all three rough inspections within a week to keep the project moving.

Common rejections during rough plumbing inspection in Allen Park: (1) drain slope less than 1/4-inch per foot — use a level and measure; (2) trap arm length exceeding code limits — measure the trap weir to the vent take-off; (3) improper pipe support — PVC and ABS must be supported at least every 4 feet horizontally and every 3 feet vertically per code; (4) missing or improperly installed vents — each fixture needs a dry vent within the allowable distance; (5) sweating copper lines not insulated or routed away from framing — condensation can rot wood in zone 5A climates. Have the inspector email or document the exact rejection reason so you can correct it precisely.

Common questions