Deck Permit in Madison, WI
Permit Summary
Do You Need a Deck Permit?
Exemptions
No general permit exemption applies to a new deck based solely on its height, area, or freestanding construction. Madison permits replacement of deck surface boards without a building permit if the work costs less than $500. For replacement of stairs, joists, beams, columns, guardrails, or other structural elements, the City directs owners to obtain a permit or have Building Inspection evaluate the specific work.
Attached / Detached Rules
Both attached and freestanding ('floating') decks require a City building permit and scaled framing plans. Attached decks need code-compliant connections and load paths to the dwelling; freestanding decks must support loads independently. Madison's checklist requires frost-depth footings for decks within 3 feet of the house or serving a dwelling exit, even when described as floating.
Egress Rules
A deck serving a required house exit must provide a safe code-compliant landing and any necessary stairs/handrails without compromising that exit. Wisconsin SPS 321.225 applies deck footing, frost-protection, loading, and stair/guard provisions to decks attached to dwellings and detached decks serving an exit; Madison's checklist expressly requires 48-inch frost footings for a deck serving a house exit.
Permit & Review Path
Permit / Review Path
For a new deck, check zoning, prepare the City Deck Data Sheet and dimensioned construction plans, and submit for Building Inspection plan review. The City offers appointment-only permit-counter review (which may result in same-day issuance for a compliant design) or the digital plan review route by email, using its one- or two-family Building Plan Review Application with PDF plans. When zoning review is needed, approval precedes permit issuance; pay the assessed fees, receive the permit, and arrange inspections. Simple nonstructural repair/replacement work may follow the City's separate online repair-or-replace route, and qualifying deck-board-only maintenance below $500 requires no permit.
Zoning & Placement Rules
Zoning Rules
Check the parcel's Madison zoning district before designing the deck. The City requires a site plan for zoning review when the deck is 3 feet or more above grade; other reviews may apply to lakefront sites, Planned Development zoning, or historic properties. Setback exceptions are governed by Madison General Ordinances 28.132 and district-specific standards.
Setback Rules
Madison says decks lower than 3 feet above grade can generally extend to the lot line, while decks 3 feet or higher must comply with the property's zoning-district setbacks, subject to permitted encroachments under MGO 28.132. There is no single citywide front, rear, and side setback for all decks. Planned Development districts and lakefront yards have additional location-specific controls.
Lot Coverage Rules
Madison zoning review materials describe decks as an exception from the general lot-coverage calculation, which otherwise measures buildings, accessory structures, and impervious surfaces against district-specific lot coverage limits. Whether other work associated with the deck, such as a roofed enclosure or paving, affects zoning coverage depends on that work and the parcel's district. The project plans must still show the deck and relevant site dimensions.
Special Area Rules
For a lakefront parcel, Madison requires a survey by a registered land surveyor showing relevant structures and setbacks from the Ordinary High Water Mark; lakefront setback provisions are governed by MGO 28.138 and allowed encroachments. Properties in Planned Development districts need site-specific zoning direction. Exterior deck additions on designated landmarks or within historic districts may require a Chapter 41 Certificate of Approval before a building permit is issued.
Structural Requirements
Structural / Load Rules
Design and size decking, joists, beams, columns, connections, and foundations to carry actual dead, live, and lateral loads under Wisconsin's Uniform Dwelling Code, including SPS 321.02 and SPS 321.225. The state's standard deck design guidance addresses an ordinary 40-pound-per-square-foot deck live load; unusually concentrated loads need separate analysis. Construction plans must show member sizes, locations, and spacing.
Foundation / Footing Rules
The City's deck page generally specifies footings at least 48 inches deep for frost protection, sized to support the deck loads. The deck submission checklist specifically requires 48-inch frost-depth footings whenever a deck is within 3 feet of the house or serves a house exit, whether attached or floating. Footings must bear on undisturbed soil; show footing size, depth, placement, and support details on the plans. Have excavated footing holes inspected before installing or pouring footings.
Ledger / House Connection Rules
Where a deck is attached to a dwelling, provide a code-compliant structural ledger connection, adequate fastener sizing/spacing, flashing against water entry, and a continuous load path. Identify the ledger size and location on the City framing plans. Wisconsin SPS 325 Appendices B and C provide prescriptive ledger/connection details for qualifying constructions; unsupported connections or nonstandard existing wall/framing conditions require project-specific review.
Guardrail Rules
Madison requires a guardrail around open sides of a deck more than 2 feet (24 inches) above ground; the guard must be at least 3 feet (36 inches) high. Wisconsin's dwelling stair and guard requirements generally limit guard openings to prevent passage of a 4 3/8-inch sphere, subject to specific stair-triangle and other code exceptions. Deck guard construction and anchorage must comply with the applicable UDC requirements.
Stair / Handrail Rules
Deck stairways with more than three risers must have at least one handrail along the flight and guards on open sides. Wisconsin UDC inspection guidance places the handrail top 30 to 38 inches above tread nosings and requires code-compliant, graspable rails, tread/riser dimensions, and landings. Madison identifies a 4 3/8-inch sphere restriction for guard openings, with code-specific exceptions at stair geometry.
Roof Deck Rules
A walkable deck built on a building or garage roof is not exempt from building plan review. Plans must establish adequate support for occupancy/loading, safe access and guards, and continued roof weather protection and drainage. Height, placement, and any historic or lakefront review depend on the particular building and parcel; Madison does not publish a separate streamlined residential roof-deck permit path on its deck page.
Heavy Load Rules
Ordinary prescriptive deck plans should not be assumed adequate for a hot tub, spa, heavy planters, or other concentrated loading. The City specifically requests structural plans when a hot tub will rest on an existing deck or floor system. Wisconsin DSPS deck guidance explains that loading outside standard prescriptive conditions needs structural engineering analysis and an appropriate support/load path.
Plans & Professional Design
Prescriptive Plan Rules
Madison links Wisconsin Uniform Dwelling Code SPS 325 Appendix B (standard deck construction) and Appendix C (additional or more complex deck/ledger details) from its deck-permit page. These state prescriptive details may be used for qualifying designs, but applicants still submit Madison's deck data sheet, dimensioned construction drawings, and any required site plan. Designs outside prescriptive conditions require additional structural information.
Professional Design Rules
A standard one- or two-family deck can be submitted with scaled plans rather than a universally required architect or engineer stamp; the City's application identifies designer information as optional. For nonstandard framing, ledger attachments, unusual structural configurations, or high concentrated loads such as hot tubs, structural calculations and professional engineering analysis may be necessary to substantiate code compliance.
Inspections
Inspection Stages
Inspect excavated footing holes after digging and before placing or pouring footings. Other applicable inspections can include exposed structural framing before it is concealed and a final inspection after deck and stair/guard work is completed; required stages depend on the approved scope. The City identifies the assigned inspector when the permit is issued and accepts inspection requests at 608-266-4551 ext. 1.
What You Need Before Applying
Requirements
Obtain a building permit before constructing a new deck, including a freestanding or floating deck. Check the property's zoning and submit scaled deck construction plans with the City deck data sheet; arrange zoning site-plan review when the deck surface is 3 feet or more above grade or other site-specific review applies. Owner-occupants may apply for qualifying work on their own one- or two-family dwelling; non-occupant rental owners generally need a properly credentialed contractor applicant. Display the issued permit visibly during construction and request required inspections.
Required Documents
Submit the completed City Deck Data Sheet and scaled deck framing/construction plans showing deck dimensions and height, location of posts, beams, joists and ledger, material sizes and spacing, stairs/rails, and footing size and depth. The City's checklist calls for two complete plan sets for paper review; its digital route requires a one- or two-family Building Plan Review Application and PDF plan set emailed to planreview@cityofmadison.com. A scaled site plan showing lot lines, structures, and distances is required for decks 3 feet or more above grade. Lakefront sites require a survey showing applicable ordinary-high-water-mark setbacks.