Do I need a permit in Shrewsbury, Missouri?

Shrewsbury is a suburban St. Louis community where most residential projects require a building permit. The City of Shrewsbury Building Department enforces the 2015 International Building Code with Missouri state amendments, plus local zoning and subdivision ordinances. The short version: decks, additions, electrical work, plumbing changes, new roofs, HVAC replacements, finished basements, fence work, and pool installation all trigger permits. Small repairs and replacements (like water-heater or HVAC swaps-in-kind) sometimes don't — but a quick call to the building department before you start is worth the 90 seconds and saves the headache of a stop-work order.

Shrewsbury's 30-inch frost depth is shallower than some Midwest cities but still binding for deck footings, foundation walls, and any post installation. The loess soil in much of Shrewsbury is stable for footings but compacts predictably — that matters for deck and shed design. Karst topography south of downtown means sink-hole risk in some areas; if you're doing any excavation or deep footing work, the building department will flag that early.

The Building Department processes most permits over-the-counter or by mail. Plan review typically takes 1–3 weeks depending on complexity. Owner-builders are allowed for owner-occupied residential work, but electrical and plumbing subcontractors must be licensed. Most homeowners find it easiest to call the department first, confirm requirements, gather documents, and submit. The process is straightforward when you lead with good information.

What's specific to Shrewsbury permits

Shrewsbury adopts the 2015 International Building Code with Missouri amendments. That's the statewide baseline, but Shrewsbury's local zoning ordinance adds lot-coverage, setback, and height restrictions that vary by zoning district. Most of Shrewsbury is R-2 (single-family residential) zoning. Lot coverage for all structures combined is capped at around 40 percent in typical residential zones — that matters if you're adding a deck, shed, or patio. Setbacks from the front, side, and rear property lines are strict; a deck or addition in the wrong spot will get flagged in plan review. Always confirm your lot's zoning district and exact setbacks before submitting — the city's zoning map and land-use ordinance are available online, or call the Planning Division to confirm.

Electrical work in Shrewsbury requires a licensed electrician's sign-off unless you're the homeowner doing owner-occupied work — and even then, a permit is required. NEC (National Electrical Code) 690.12 governs solar installations; Missouri adopted it statewide. Panel upgrades, new circuits, subpanels, and outdoor wiring all need electrical subpermits. The electrician or the homeowner files the subpermit; it's usually bundled with the main building permit fee but sometimes billed separately ($50–$150 depending on scope). Plumbing work (new fixtures, drain/vent changes, water-line relocations) follows the 2015 IPC (International Plumbing Code) as adopted in Missouri. Licensed plumbers aren't always required for homeowner work in Missouri, but Shrewsbury will almost certainly require a plumbing subpermit and a licensed contractor's sign-off; confirm before you start.

Deck permits in Shrewsbury trigger for any deck larger than roughly 200 square feet or any deck more than 30 inches above grade. The frost depth is 30 inches, so footings must bottom out below 30 inches and sit on undisturbed soil — typically 36 inches to be safe. Posts must be pressure-treated, and guardrails are required if the deck is over 30 inches above grade. The building department will want a site plan showing the deck's location relative to property lines and setbacks, footing details, and guardrail specs. Most deck permits are approved in 1–2 weeks if the paperwork is complete on first submittal.

Fence permits are required for any fence over 6 feet and for any fence in a corner-lot sight triangle (usually 25–30 feet from the corner). Pool fencing is always required, even for above-ground pools, because Missouri pool safety laws (RSMo Section 537.400) mandate 4-sided barrier fencing at least 4 feet high. The building department will inspect the fence after installation to confirm it meets setback and height specs. Flat-fee fence permits in Shrewsbury typically cost $50–$100; plan on a 1–2 week turnaround.

Roof replacements don't always need a permit in Shrewsbury if they're purely like-for-like (same material, same pitch, no structural work). But if you're changing the roof type (e.g., asphalt to metal, or adding new ventilation), a permit is required. Roofing subpermits usually cost $50–$150. HVAC replacements (same-ton, same location) are often exempt, but new equipment, relocated units, or ductwork changes require a permit and inspection. The same goes for water-heater replacements: swapping an old tank for an identical new one is usually exempt, but any change in location or type (tank to tankless, gas to electric) needs a permit.

Most common Shrewsbury permit projects

These are the projects that trigger permits most often in Shrewsbury. Click through for detail on each, or call the Building Department to confirm your specific scope.

Shrewsbury Building Department contact

City of Shrewsbury Building Department
Contact City Hall, Shrewsbury, MO (verify current address and location locally)
Call the City of Shrewsbury main line or search 'Shrewsbury MO building permit phone' to confirm the direct number
Monday–Friday, 8 AM–5 PM (verify locally; hours may shift seasonally or due to staffing)

Online permit portal →

Missouri context for Shrewsbury permits

Missouri has no state residential permit requirement — permitting is entirely municipal. Shrewsbury, like most St. Louis suburbs, enforces local building codes based on the 2015 International Building Code (IBC), International Plumbing Code (IPC), and National Electrical Code (NEC). Missouri's State Fire Marshal has authority over fire-safety aspects of the code, particularly for commercial and multi-family work, but Shrewsbury residential permits fall to the local building department.

Missouri allows owner-builders to pull permits for owner-occupied residential work, but trades (electrical, plumbing, HVAC) must be licensed. Missouri's electrical license is administered by the Division of Professional Regulation. A licensed electrician can pull the subpermit and do the work, or a homeowner can pull the electrical permit if doing owner work — but most jurisdictions, including Shrewsbury, require the final sign-off from a licensed pro. Call ahead to confirm Shrewsbury's exact rules on homeowner vs. licensed work.

St. Louis County (where Shrewsbury is located) has a 30-inch frost depth. Footings must go below 30 inches or risk frost heave during the freeze-thaw cycle. The loess soil in the area is stable once properly compacted, but it settles over time if not undisturbed — the building code requires post footings to sit on undisturbed soil, not fill. If your lot has been graded or filled, the building department may require a soils engineer's letter. Karst topography (sinkholes and underground caves) is present south of downtown Shrewsbury; if your project involves excavation, mention it to the building department so they can flag any sinkhole-risk areas before you dig.

Common questions

Do I need a permit for a small deck or patio?

Decks over roughly 200 square feet or more than 30 inches above grade require a permit in Shrewsbury. Patios at grade level (no elevated deck) typically don't need a permit unless they exceed a certain lot-coverage threshold — check your zoning district's max lot coverage. Porches attached to the house and enclosed by a roof usually need a permit because they're considered an addition to the home footprint. Call the building department with your deck or patio dimensions and height to get a straight answer; most calls take less than 5 minutes.

What does a typical residential building permit cost in Shrewsbury?

Shrewsbury permit fees are based on project valuation. Most jurisdictions charge 1.5–2% of the construction value as the base permit fee, plus subpermit fees for electrical ($50–$150), plumbing ($50–$150), and mechanical work ($50–$150). A $25,000 deck project might cost $375–$500 in total permits. A $15,000 room addition might cost $225–$300 plus electrical and plumbing subpermits. Call the building department with your project scope and rough budget to get a fee estimate — there are no surprises once you ask.

How long does plan review take for a building permit in Shrewsbury?

Routine residential permits (decks, fences, sheds, single-room additions) typically clear in 1–3 weeks, depending on completeness of the submitted plans. If the application is incomplete or the plans don't match the code, expect a round of corrections and a 1–2 week wait for re-review. Complex projects (whole-home additions, major electrical upgrades, HVAC relocations) may take 3–6 weeks. The building department will tell you the expected timeline when you submit. Over-the-counter permits (simple fences, small sheds) sometimes clear the same day or within a few days.

Can I do the work myself, or do I need a contractor?

Missouri allows owner-builders to pull and file permits for owner-occupied residential work. However, electrical work must be either done by a licensed electrician or pulled as an owner-builder permit and inspected by the city — most jurisdictions, including Shrewsbury, require a licensed electrician's sign-off. Same for plumbing in many cases. HVAC and gas-line work almost always require a licensed contractor. The safest approach: hire a licensed contractor, let them pull the permits, do the work, and handle inspections. If you're doing some work yourself, call the building department first to understand what's allowed in Shrewsbury.

What happens if I start work without a permit?

If the city discovers unpermitted work (often during a later inspection, a neighbor complaint, or title work before a sale), you'll receive a stop-work order and will have to halt work immediately. Then you face choices: finish obtaining the permit and pay a late-filing penalty, or tear out the work and restore the property. Late-filing penalties can range from the full permit fee up to 3x the base fee, depending on how long you worked without a permit. On resale, unpermitted work can block the sale, kill the financing, or force you to tear it out. The permit cost upfront — usually $100–$500 — is a bargain compared to fixing it later.

Does Shrewsbury have an online permit portal?

As of this writing, it's unclear whether Shrewsbury offers online filing. Search 'Shrewsbury MO building permit portal' or call the Building Department directly to ask whether you can submit applications online, check permit status online, or schedule inspections through a web portal. If online filing isn't available, you'll file in person at City Hall or by mail with paper copies of your plans and application.

What about pool permits and safety barriers?

Above-ground and in-ground pools trigger a permit in Missouri and must meet pool-safety requirements under RSMo Section 537.400. A 4-sided barrier (fence or wall) at least 4 feet high is required on all sides. Gates must be self-closing and self-latching. The building department will inspect the barrier and the pool installation before issuing a certificate of compliance. Pool permits typically cost $100–$250 and take 1–2 weeks to approve. Don't install a pool without a permit; it's one of the easiest violations for inspectors to spot and one of the hardest to fix retroactively.

Ready to move forward?

Start by calling the City of Shrewsbury Building Department and describing your project. Have your address, lot size, and project scope ready. A 5-minute conversation will tell you whether you need a permit, what it costs, and what paperwork you'll need to submit. If you do need a permit, ask for a checklist of required documents — that's your roadmap for getting an approval on the first try, not the third.