Do Porch and Deck Stairs Need Footings in Chicago?

Do deck stairs need footings in Chicago? In practice, yes: the stair has to land on something solid that will not sink or lift with the seasons, and the City's own guidance describes footings that reach well below grade. The exact rule for a given stair, especially one landing on an existing slab, is something to confirm with the Department of Buildings (DOB) rather than assume.

What does Chicago say about footings under porches and decks?

Two pieces of City guidance matter. First, DOB says inspectors check the joists, beams, columns, stairs, hand and guard rails, ledger boards, connections and footings on a porch or deck (City of Chicago). So the support under the stairs is part of what gets looked at.

Second, DOB's Porch Design and Construction Guidelines from May 2011 say footings must have the bottom at least 42 inches below grade. They also say guards must be at least 42 inches high. That guide cites pre-2019 code chapters, so the numbers should be read as 2011 City guidance and checked against the current Building Code. That is the honest limit of what we can say. We do not have a verified current-code number for stair footings specifically, so ask DOB.

Why does the bottom of a stair need support?

A stair is a heavy, repeatedly loaded structure with its feet in the one place that gets the most water. If the bottom sits on soil or a loose pad, two things happen over time. The ground under it settles or freezes and lifts, and the stair moves out of level or pulls away from the porch. And wood that touches the ground rots: ground contact needs lumber treated to at least Use Category 4A (AWPA).

A stair that lands on a stable concrete pad or a footing, with the wood kept off the soil, avoids both. For the wood side of the problem, see back porch stairs, and for the material choice, concrete or wood porch stairs.

Does building or fixing a footing need a permit?

Often yes. The Department of Buildings says a permit is always required to repair or replace structural elements such as columns, beams, foundations, stringers and floor joists, with plans by an Illinois-licensed architect or structural engineer. Replacing only treads, deck boards or railing pickets needs no permit if you have no violation (City of Chicago). A new footing is foundation work. The City's maintenance standard also says exterior stairways and porches must be structurally sound, properly anchored and capable of supporting the imposed loads (City of Chicago).

Rules change. Confirm current requirements with DOB before you dig. When you want it built and permitted correctly, our porch team can handle the drawings and the work, and the Chicago porch guide covers the rest. For the guard side of the same stair, see porch railing height.

Common questions

This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.