Concrete or Wood Porch Stairs for Chicago Winters

If you are weighing concrete stairs vs wooden stairs for a Chicago porch, the honest answer is that the material matters less than how the stairs are built, drained and anchored. Here is how each one fails in our winters, and what to ask before you choose.

How do wood porch stairs fail in a Chicago winter?

Wood fails from water, not from cold. Serious decay starts only when the wood stays above about 30 percent moisture, and the U.S. Forest Service says that comes from rain, condensation or wet ground contact, not from humid air alone (USDA Wood Handbook). So wood stairs rot where water sits: at the bottom of the stringers, at the treads' ends, at the joints where the stair meets the landing.

Wood that touches the ground needs the right treatment. AWPA says ground-contact applications require use category UC4A or higher (AWPA). Fasteners matter too. The American Wood Council guide calls for hot-dipped galvanized or stainless steel hardware with treated wood (AWC DCA 6). Ordinary screws on treated lumber are a common shortcut. For the full rot-and-rebuild picture, see back porch stairs in Chicago.

How do concrete porch stairs fail?

Concrete does not rot. It scales. Scaling is surface flaking from freeze-thaw exposure, and de-icers make it worse by keeping the surface saturated and adding freeze-thaw cycles (NRMCA). Concrete that sees freeze-thaw while wet should be air-entrained (NRMCA). A bad mix, poor finishing or too much de-icer, especially in the first winter, are the usual causes. By a rough count from National Weather Service normals, about 78 days a year in Chicago start below freezing and climb above it. That is a derived estimate, not an official cycle count, but it explains why stairs here take a beating (NWS normals).

Scaled concrete can sometimes be resurfaced if the damage is light to moderate, but the repair only holds as well as the base under it, and it will not match the original color (NRMCA). If you go with concrete, ask for the mix to be specified for freeze-thaw, and use sand, not salt, on the first winter (NRMCA).

What matters more than the material?

Support. The City's maintenance standard says exterior stairways and porches must be structurally sound, in good repair, properly anchored, and capable of supporting the loads on them (Chicago 14X). The Department of Buildings (DOB) says inspectors check stairs, connections and footings (DOB porch safety). DOB's 2011 porch guidelines call for footings with the bottom at least 42 inches below grade. That guide cites older code chapters, so confirm the current rule with DOB before you rely on the number (DOB guidelines). We cover the footing question in do porch stairs need footings.

A concrete stair that sits on poor support will crack and settle. A wood stair on a perfect footing will still rot if water has nowhere to go. Pick the material that fits how your porch drains, then pay for the support.

Do you need a permit to swap them?

It depends on what is changing. DOB says replacing non-structural parts such as stair treads does not need a permit if you have not received a violation, but repairing or replacing structural elements such as stringers and foundations always does, with plans from an Illinois-licensed architect or structural engineer (DOB porch safety). Express Permit rules also treat a change in configuration as outside simple in-kind replacement (City of Chicago). Switching from wood stairs to concrete is a change, so ask DOB first. For the bigger picture, see our Chicago porch guide and the porch crew.

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.