Short answer
Yes. Wisconsin requires a building permit from your city, village or town before an addition is started. The electrical, plumbing and heating work inside it usually needs separate permits. Only a certified dwelling contractor, or an owner who lives in the home, can obtain the building permit. Generations pulls every permit for its clients and books the inspections.
Key takeaways
- The permit comes from your local building department, and plan review checks both the building code and the zoning rules for your lot.
- Wisconsin’s Uniform Dwelling Code (SPS 320 to 325) covers additions to homes built under it (SPS 320.04); for older homes, your municipality’s ordinance decides (SPS 320.05).
- Under SPS 305.31, the permit goes to a Dwelling Contractor certification holder, or to an owner who lives in the home.
- The UDC permit application includes an erosion control plan when the addition disturbs soil.
- Inspections run from the foundation through rough-in and insulation to a final inspection before the new space is used (SPS 320.10).
When a home addition needs a permit
Any addition that adds floor area to a house needs a building permit in Wisconsin. That includes a bump-out for a bigger kitchen, a family room off the back, a primary suite and a second story.
The permit has to be issued before excavation or framing starts. Electrical, plumbing and heating work inside the addition usually needs its own permits too, from the same local office.
Your city, village or town issues the permit, not the state. Every municipality in Milwaukee and Waukesha County handles its own permits, so forms and fees change from one address to the next.
Tip
Ask the building department for the zoning rules on your lot before anyone draws plans. Setbacks and lot coverage decide how large the addition can be.
Which building code applies to your addition
Wisconsin’s Uniform Dwelling Code, chapters SPS 320 to 325, sets the construction rules for one- and two-family homes. It covers additions to homes that were built under it.
For homes started before the code took effect, SPS 320.05 says the state code does not reach additions on its own. A municipality may adopt the code for additions and alterations to older homes. Several local ordinances apply it to homes built before June 1, 1980.
Where the code applies, the addition must meet the version in force when the permit application is filed. The bathroom permit guide walks through those code chapters one by one.
What goes into an addition permit application
Expect to submit more than a form. A typical application for an addition includes:
- Construction plans: floor plans, sections and framing details for the new space.
- A site plan or survey: where the addition sits on the lot and how far it is from each property line. The Village of Menomonee Falls, for example, asks for a survey and a construction plan for a residential addition.
- An erosion control plan: under the UDC it is submitted with the permit application. DSPS rules cover sites that disturb less than an acre of land, which includes nearly every home addition.
- Trade permits: separate applications for the electrical, plumbing and heating work.
Plan review checks the plans against the building code and the site plan against zoning, including how close the addition comes to each property line.
Who can pull the permit for an addition
Under SPS 305.31, only a Dwelling Contractor certification holder can get a building permit for a one- or two-family home. That contractor must also be, or employ, a certified Dwelling Contractor Qualifier.
The exception is the owner. An owner who lives in the home, or will, can apply without the certification, usually by signing an owner-occupant affidavit. Municipalities must also give owners a cautionary statement about hiring a contractor who is not bonded or insured.
Generations is licensed in Wisconsin and pulls the permits for every client, so the applications and inspection bookings are handled for you.
Inspections during a home addition
SPS 320.10 sets the inspections for work under the Uniform Dwelling Code. For an addition, they run in this order:
- Foundation excavation. Checked after the forms and any required reinforcement are in place, before the foundation is poured.
- Foundation. Inspected once complete, and before backfilling where dampproofing, exterior insulation or drain tile is required.
- Rough-in. The rough framing, electrical, plumbing and heating work, inspected before anything is covered. One combined visit or separate visits are both allowed.
- Insulation. Insulation and vapor retarders are checked after they go in and before the drywall.
- Final. The new space may not be used as living space until a final inspection finds no critical violations.
Erosion control is checked during each of these visits. A state-certified inspector does every inspection and records each visit and its result.
Addition permit offices around Milwaukee and Waukesha County
Each community handles addition permits a little differently. A few examples from the areas we serve:
- Wauwatosa: the Building & Safety Division takes permit applications through the city’s online self-service portal. Our page on remodeling in Wauwatosa covers the city in more detail.
- Milwaukee: permits and plan review run through the Department of Neighborhood Services.
- Brookfield: an address may sit in the City or in the Town of Brookfield. Each runs its own permit office, so we check which one applies first.
- Elm Grove: the village requires a permit before work begins and doubles the fee for work started without one.
- Menomonee Falls: the village asks for a survey and a construction plan with an addition application.
How Generations handles addition permits
An addition starts with a free walkthrough. On site we check the house, the lot and how the new space should connect. You receive a written scope, price and warranty, and you pay nothing until you sign off on them.
From there we prepare the applications, pull the permits and book each inspection. Alexis Quesada is your single point of contact for the whole build, and our in-house crew does the construction.
Our home additions page shows the types of additions we build, and our framing page covers the structure behind them.