Fall Exterior Repairs Before Winter: What to Finish in Chicago

Fall exterior repairs before winter come down to one rule: finish anything that lets water in, and anything that needs fresh mortar or concrete, while the weather still cooperates. Water that gets into a Chicago building in November freezes in December, and every freeze pushes the opening wider. Here is the order we would work in, and why.

Why does October matter so much in Chicago?

Because the calendar turns on you quickly. In the 1991 to 2020 normals, Chicago averages 0.2 inches of snow in October, 1.8 in November and 7.6 in December. The first real snow looks like it is a long way off, and then it is not.

The bigger issue is freezing nights. Chicago averages about 121 days a year with a low at or below 32 F, and about 43 days when the high stays at or below 32 F. The gap between those two numbers is roughly 78 days a year when a wet wall freezes overnight and thaws by afternoon. That is the cycle that turns a hairline gap into a loose brick. For the full mechanism, see how freeze-thaw damages a Chicago building.

So the fall job is simple: get water out of the places it should not be, before it can freeze there.

Which repairs should come first?

Work in this order. The top of the list is what you cannot ignore.

1. Roof and flashing. Anything that leaks gets worse all winter, and you cannot repair most roofing in snow. The City says no permit is needed for roof repair limited to 25 percent of the roof area as long as no part of an exterior wall or roof is cut away. Bigger or structural roof work needs a permit, so confirm with the Department of Buildings first.
2. Parapets, chimneys and copings. These sit in the weather on every side. A loose cap or cracked parapet joint takes in water from above and below.
3. Open mortar joints. The Chicago code says the exterior of a structure must be kept in good repair, and unsafe conditions include masonry joints that are not weather resistant or water tight. Open joints are both a freeze-thaw problem and a violation waiting for a 311 call.
4. Loose or spalling brick, cracked lintels. Water that gets behind a loose face brick freezes and pops the face off.
5. Gutters, downspouts and grade. Water coming off the roof should leave the building, not sit against it.
6. Porch and stair repairs. Exterior stairs, porches and guards must be structurally sound and properly anchored under the same maintenance rule. Winter ice makes a weak step much worse.
7. Small concrete repairs. Last on the list, because concrete is the most weather-sensitive of the group. More on that below.

What does cold weather do to fresh mortar?

Mortar has to cure, and cold stops that. The masonry industry's rules, summarized by the Brick Industry Association from TMS 602, treat any temperature below 40 F as cold weather for masonry. The same summary says that:

• between 40 and 32 F, mortar should be mixed between 40 and 120 F;
• below 32 F, the mortar has to be kept above freezing and the work protected;
• below 20 F, crews should not lay units that are below 20 F or carry frozen moisture, ice or snow, and enclosures are needed to keep the masonry above 32 F.

Those are the rules for laying new masonry, and repointing uses the same material with the same weakness. The National Park Service guidance on repointing says wall temperatures between 40 and 95 F prevent freezing or excessive evaporation of mortar water, and it advises against antifreeze additives, which can leave salts that bloom later. A contractor who tells you winter tuckpointing is no different from summer tuckpointing is skipping the hard part.

If your wall needs tuckpointing, the City lists it as permitted masonry work under its Express Permit masonry category, so a permit and a license are part of the job at any time of year. The practical point for fall is scheduling: book early enough that the crew can finish while days are still above 40 F.

What does cold weather do to fresh concrete?

Concrete is less forgiving than mortar. Fresh concrete freezes at about 25 F, and frozen fresh concrete can lose more than half of its potential strength. The National Ready Mixed Concrete Association says to protect it from freezing until it reaches 500 psi, about two days after placement.

The industry also has a formal trigger. The older definition of cold weather is more than three consecutive days with an average temperature under 40 F, and newer ACI practice applies cold weather provisions whenever the air temperature is below, or expected to fall below, 40 F during the protection period. Which edition governs depends on the code adopted, so we do not treat November as a safe month for flatwork.

In plain terms: a new banqueta (sidewalk) panel, porch landing, step or patch poured late in the season is a risk. If a repair can be done as a fall job, do it in October. If it cannot, a competent contractor will tell you to wait for spring and make the area safe in the meantime. That is not an upsell. It is how you avoid paying twice.

What should you do about gutters and grade?

This one is DIY-safe for many owners, and it costs little compared with what it prevents. Clear the gutters after the leaves drop, check that downspouts are attached and that every joint is tight, and look at where the water goes when it leaves.

University of Minnesota Extension advises sloping soil away from the foundation at least 1 inch per foot for at least 6 feet, with downspout extensions or splash blocks that discharge at least 4 feet from the wall. That guidance is general building science rather than a Chicago rule, but the physics is the same here. Backfill settles over the years and often ends up sloping toward the house.

If gutters have pulled away from the fascia, or a downspout empties onto a masonry wall, that is a repair, not a cleaning job.

What can safely wait until spring?

Not everything has to happen now. These usually can wait:

• Cosmetic masonry cleaning and efflorescence cleanup.
• Cosmetic concrete issues that are not trip hazards or drainage problems.
• Paint and sealing work that needs warm, dry days.
• Planning and estimates for larger jobs, which is a good use of the winter. See what exterior work can happen in a Chicago winter and the best time of year for each repair.

What cannot wait is anything that lets water in or that creates a fall hazard.

How do you know what your building needs?

Walk the outside once, slowly, with binoculars if you have them. Look at the roof edge, chimney, parapet, mortar joints, window heads, porch posts and the point where each downspout lands. Write down what you see, with photos. Then call someone to confirm what you cannot judge from the ground.

Our seasonal maintenance checklists lay out the full calendar. If you want a second set of eyes before the cold, Akats can look at the building and tell you what has to be done this fall and what can wait, through our exterior repair services. We are licensed and insured in Illinois, and we speak English and Spanish.

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.