Why October is the last good month for tuckpointing in Evansville

September 8, 2026

Evansville’s average first fall freeze is October 29, per the National Weather Service office in Paducah, and mortar should be placed with wall temperatures between 40 and 95 degrees Fahrenheit, per the National Park Service’s Preservation Brief 2. Put those two facts together and October is the last month of the year in which a normal tuckpointing job can be scheduled, placed, tooled, and cured without fighting the weather. That is not a sales deadline. It is arithmetic, and it repeats every year.

What actually happens to mortar in the cold

Fresh mortar is a wet mix that gains strength through hydration and, in lime-rich mixes, through carbonation as it takes up carbon dioxide from the air. Both processes need liquid water and time. If the water in a fresh joint freezes before the mortar has developed strength, the ice expands inside the joint, breaks up the structure that was forming, and leaves you with a joint that is crumbly, chalky, poorly bonded, or all three.

The cruel part is the timing of the discovery. A frozen joint often looks fine in November. It sits there through the winter looking like a finished job. Then the first real wet spring arrives, water gets into a joint that never bonded, and by the following summer the repair is loose or gone. That is why a careful mason would rather turn down a late job than place it badly: the customer pays twice, and the second time includes cutting out the first mason’s mortar.

Preservation Brief 2 also warns off the shortcut people reach for. Antifreeze compounds are not recommended, because they are not very effective with high lime mortars and may introduce salts, which then cause efflorescence later. The recommended practice instead is to warm the sand and water and protect the completed work from freezing. That is doable, and it is exactly what a proper winter enclosure does. It also costs money, which is the honest reason to close your joints in the fall.

The Evansville numbers

Two data sets set the season here.

The freeze dates. NWS Paducah puts the Evansville area’s average last spring freeze at April 6 and the average first fall freeze at October 29. Those are averages, not guarantees, and any given year runs earlier or later. What matters for scheduling is that after the last week of October the odds of a freezing night inside any given week climb quickly.

The freeze-thaw count. NOAA’s 1991-2020 normals for Evansville Regional Airport count 92.6 nights a year with a low at or below 32 degrees but only 15.5 days with a high at or below 32. The difference, roughly 77 days, is the number that matters to a brick wall: on those days the wall freezes overnight and thaws by afternoon. December averages 19.8 freezing nights, January 23.6, February 19.2, and March still 11.9.

That last set is also why open joints in October are not a cosmetic problem. Every one of those 77 cycles is a chance for water sitting in an open joint to freeze, expand, and take a little more mortar with it. A joint that is hairline in October is measurably wider in March. Do that for three winters and the brick face goes too, which turns an $8 to $20 per square foot repointing job into that plus brick replacement at $20 to $40 a unit. The crumbling mortar page and the spalling brick page show both stages.

What cure actually requires

The reason a mason cannot simply work faster in a cold week is that curing is not instantaneous, and Preservation Brief 2 describes the sequence in detail.

Joints are cut to a minimum of 2 to 2.5 times the joint width, which is roughly half an inch to an inch on most brick. They are rinsed clean and left damp with no standing water. Mortar goes in in layers of about a quarter inch, and each layer has to reach thumbprint hardness before the next goes on, because most of the shrinkage happens during that hardening. When the final layer is thumbprint hard, the joint is tooled to match the original profile, and the timing of that tooling decides the color: too soon and it comes out light with hairline cracks, too late and you get dark streaks called tool burning.

Then the curing. High-lime mortars, the ones that belong on Evansville’s pre-1930 brick, harden as water leaves them, and drying too fast causes chalking, poor adhesion, and poor durability. So the wall gets misted with a fine nozzle, possibly as often as hourly at first, tapering to every three or four hours, and covered with burlap for the first three days. All of that assumes the wall stays above freezing the whole time. In late October it usually does. In mid-November it is a gamble on the ten-day forecast.

The fall triage list

If you are reading this in September or October and cannot do everything, do the work in this order. It is the order in which water gets into an Evansville house.

1. The chimney crown and cap. The top of the stack lets water into the whole chimney and it is the cheapest fix on the list at $400 to $1,200 for a cast crown with a drip edge. Skip it and next year’s conversation is a rebuild from the roofline at $2,500 to $7,000. See the cracked chimney crown page.
2. Open joints on the chimney itself. Repointing a stack is $800 to $2,500, and a chimney is exposed on four sides, so it fails first on every house here.
3. Anything overhead that can fall. Loose brick over a walk or a driveway is a safety issue before it is a masonry issue. The loose brick page covers it.
4. Sills that have lost their slope or their drip. A failed limestone sill pushes water into the wall under every window it serves, at $300 to $1,200 per sill to fix.
5. The north and west elevations. They dry slowest and freeze longest.
6. Gutters and downspouts. Not masonry, nearly free, and the single highest-return thing on this list. A downspout that dumps at the foundation puts more water into a wall than any other defect.

Numbers six through one is also a decent way to spend a Saturday with a ladder and a phone camera before you call anyone.

What to do if the season runs out

If the forecast closes the window before the work is scheduled, there are three honest options.

Do the urgent part under protection. A chimney that is open to the weather, a wall dropping brick, or a hole in a foundation wall is worth doing in winter. Winter work under heated enclosures typically adds 15 to 30 percent to the price, and that is what it costs to warm materials, tent the work, and protect it through cure.

Do a temporary measure and schedule April. Sometimes the right answer is covering an open chimney top, redirecting a downspout, and putting the real repair on the calendar for spring. That is a legitimate recommendation and you should be given it when it applies.

Book early for April. The season here runs April to November, which means every mason in the Tri-State has the same eight months. Work booked in October and February for April tends to be scheduled better and priced better than work booked in April for April.

Getting a number before the weather decides for you

Send a wide shot of each elevation, a close-up of the worst joints with a coin in frame for scale, the chimney from the ground, and any crack over a window. You get a diagnosis and a number from the ranges on the pricing page, and if the honest answer is that the field of your wall is fine and only the chimney and two sills need work before winter, that is the answer you should hear. The tuckpointing cost estimator and the chimney repair cost estimator will both give you a range in a minute without an email.

One last note for owners in the preservation areas: review takes time, and time is the resource October is short on. If your house is in Riverside or another designated area, start the conversation with the Historic Preservation Officer weeks before you want the scaffold up, not the week of.