Do You Need a Permit for a Deck in Michigan? What to Know Before You Build or Replace

If you're planning a new deck or tearing off an old one, the permit question usually comes up before the lumber order does. The short answer in Michigan: if the deck is attached to your house, you almost certainly need a permit. That surprises a lot of homeowners, because they've heard about a size cutoff and assume their deck falls under it.

Here's how the rules work, what inspectors look at, and where a permit is worth pulling even when you're on the borderline. One caveat up front: your city or township building department has the final say, so call them before you start.

What the Michigan code says about deck permits

Michigan builds its residential rules on the International Residential Code with state changes. Under the state's list of work that is exempt from a building permit, a deck can skip the permit only if it meets all of these conditions:

• It's 200 square feet or less.

• No part of it is more than 30 inches above grade.

• It isn't attached to the house or an accessory structure like a garage.

• It's at least 36 inches away from the house or garage.

• It doesn't serve an exterior door.

Miss any one of those and you're in permit territory. A 12-by-14 deck is only 168 square feet, but if it's bolted to the house and sits at the back door, it needs a permit anyway. Size alone doesn't get you out of it.

Some cities and townships are stricter than the state exemption, and a few want a permit for every deck. Ask your local building department instead of guessing from a neighbor's experience.

Why attached decks get so much attention

The ledger board is the reason. It's the board that fastens the deck to your house, and it's one of the most common places a deck fails. If it's held on with nails instead of through-bolts or lag screws, or if flashing is missing and water gets behind it, the deck can pull away from the wall. That's a serious injury risk, not a cosmetic problem.

Many Michigan building departments spell out the details: the ledger fastens to solid framing, not just the rim board covering, with corrosion-resistant bolts or lags, and flashing goes over the connection. Once the decking is down, none of that is visible. That's the whole point of the inspection.

Replacing an existing deck still counts

A lot of people figure swapping old boards for new ones isn't really building anything. Replacing the surface boards on a deck whose framing is sound is usually treated as repair, and many departments don't require a permit for that. Replacing joists, beams, posts, footings, or the ledger is different. That's structural work, and most building departments want a permit for it. If you're not sure which side your project falls on, a two-minute phone call settles it.

If your deck has a soft spot, rotted joist ends, a wobbly railing, or a ledger that looks like it's pulling away from the house, don't treat that as a permit question first. Treat it as a safety question and have a licensed contractor look at it before anyone steps on it again.

What inspectors typically check

Details vary by municipality, but a deck inspection usually covers these items:

• Footings: they have to sit below the frost line. The figure commonly used in Michigan is 42 inches from the bottom of the footing to grade, but confirm it with your local office.

• Posts and beams: correct sizes for the span, proper connectors, and solid bearing on the footings.

• Ledger: through-bolts or lags into solid framing, with flashing over the connection.

• Joists: the right size and spacing, with hangers installed the way the manufacturer specifies.

• Guards (railings): generally required when the walking surface is more than 30 inches above grade. Guards are typically at least 36 inches tall, with openings small enough that a 4-inch sphere can't pass through.

• Stairs: even riser heights, graspable handrails, and guards where the drop requires them.

What skipping a permit can cost you

Permit fees vary by city and township and usually depend on the size or value of the project, so call for the actual number instead of trusting a figure from a website. What we can tell you is what skipping the permit risks: a stop-work order, the expense of opening up finished work so an inspector can see it, and headaches when you sell the house. Buyers' inspectors often ask about permits for decks and additions. If a deck ever fails and someone gets hurt, an unpermitted, uninspected deck is a bad place to be standing with your insurance company.

We don't recommend skipping a permit on any deck that needs one. The inspection is cheap compared to rebuilding a deck that was built wrong.

Other things that come up before you dig

• Call MISS DIG (811) before any footing hole is dug. It's free, and it keeps you from hitting a buried gas, electric, or water line. Call a few working days ahead.

• Zoning and setbacks apply even to decks that don't need a building permit. Your deck still has to sit far enough from the property line.

• If you have a homeowners association, check its rules on size, materials, and railings.

• A hot tub changes everything. Water is heavy, and the framing and footings need to be designed for that load.

DIY or hire a pro for a deck?

A low, freestanding deck is a reasonable project for a skilled DIYer who is willing to read the code and call for inspections. A deck attached to the house, a deck high off the ground, or one that will carry a hot tub is where a licensed contractor earns the fee. The ledger connection and the footings below the frost line are the parts you can't redo cheaply, and they're the parts that hurt people when they fail.

If you hire it out, ask to see the contractor's Michigan builder license, and ask who is pulling the permit. A reputable contractor pulls it in their own name and includes it in the quote. If someone suggests you pull it as the homeowner so they don't have to deal with the building department, or suggests skipping it, that's a reason to keep looking.

A quick checklist before you start

• Call your city or township building department and ask about the permit for your exact deck.

• Ask about zoning, setbacks, and the inspection schedule.

• Call MISS DIG before digging.

• Check your homeowners association rules if you have one.

• Sketch the plan: size, height above grade, footing locations, and how the ledger attaches.

• If you hire out the work, confirm the license and who pulls the permit.

Dynamic Renovations builds and repairs decks in Ann Arbor and Southeast Michigan. If you're planning a deck, or you're not sure your current one is safe, call (734) 864-6562 or visit https://www.dynamicrenovationsllc.com/.