Shared Walls, Soft Brick and a National Park: Pest Control in Historic Pullman

A planned railcar town built as one connected structure

George Pullman built his model town in the early 1880s beside his railcar works on the west shore of Lake Calumet. Architect Solon Spencer Beman designed the housing and Nathan F. Barrett laid out the landscape, including the formal garden that survives as Arcade Park. Workers got rowhouses with indoor plumbing, gas and sewer connections, rare for the period, and Beman varied rooflines and facades so long rows would not look repetitive. Larger homes for managers stood near the Hotel Florence, while simpler rows and block flats went up farther from the center.

After the 1894 strike and Pullman's death in 1897, the Illinois Supreme Court ordered the sale of the town's housing, and the homes passed into private hands. The area had already become part of Chicago when Hyde Park Township voted to join the city in 1889. Residents defeated a 1960 plan to clear the old town for industry, and the district became a National Historic Landmark District in 1969, a state landmark in 1970 and a Chicago Landmark district south of 111th Street in 1972. It was named a national monument in 2015 and redesignated a national historical park in 2022. Most homes are still privately owned, so pest problems are handled one household at a time inside rows that were designed and built as a single system.

The materials matter as much as the plan. The town's common brick was made from clay taken from the Lake Calumet area, fired soft by modern standards and laid in lime mortar that was meant to flex and breathe. Over fourteen decades that mortar has eroded at joints, around window lintels and where porches and stoops meet the walls, opening exactly the gaps that mice, bats and insects exploit. The same softness makes the repair choices delicate. A patch that is harder than the brick around it will eventually crack the brick itself, which is why material selection comes up on almost every pest job here.

Mice that travel the length of a row

The defining pest problem in the historic town is house mice moving between attached homes. Party walls in 140-year-old rows are seldom continuous barriers. Lime mortar has softened, pipe chases were cut between units as plumbing was updated, and the floor joists of neighboring houses often bear on the same masonry pockets. Attic spaces above some rows connect, or nearly connect, across several units. Mice use every one of these routes. An owner who traps diligently may clear one house only to hear activity resume a week later as mice arrive from next door.

The usual signs are droppings along the base of the shared wall, nesting material in the void behind kitchen cabinets, chewed corners on pantry boxes and light scratching overhead where attic spaces meet. Activity rises from October through March, though rows near the rail line and open ground see mice all year. Because the source can be two or three doors away, the household seeing the most mice is not always the one with the nest.

The most effective approach is coordinated. When two or three neighboring owners book inspection and exclusion together, the technician can trace runways along the row and close gaps on both sides of a shared wall. Sealing materials matter as well. Hard Portland cement patches can crack soft historic brick and trap moisture, so experienced providers use copper mesh, removable sealants or lime-compatible mortar where gaps meet original masonry.

Bats, birds and raccoons in Beman's rooflines

The steep gables, dormers, chimneys and decorative trim that make these rows so handsome are also full of small openings. Big brown bats can slip through a gap of about half an inch at a roof edge or around chimney flashing, then roost in attics and wall voids. Little brown bats turn up occasionally as well. Both are protected and eat large numbers of insects, and Illinois specialists avoid exclusion during the summer maternity period, when flightless pups would be trapped inside. Late summer and early fall are the usual windows, using one-way valves at each entry point before the openings are sealed.

Pigeons and house sparrows nest on ledges, in gutters and inside damaged soffits, while European starlings force their way into vent openings each spring and pack them with grass and feathers. Raccoons occasionally reach attics through uncapped chimneys, especially in late winter when females look for a dry den. Any roofline repair in the landmark district should match original materials and profiles, so wildlife specialists often coordinate with roofers who have done historic work before.

Stone basements, oriental cockroaches and rats along the tracks

Many original rowhouses have stone or brick foundations with old floor drains and little waterproofing. Oriental cockroaches, the large, dark, slow-moving species that prefers cool, damp places, live in drain lines and crawl up through floor drains or along wet foundation walls, especially in late spring. They are a different problem from the small German cockroaches of kitchens and need moisture control plus targeted treatment of drains and cracks rather than kitchen baits. Fixing leaky gutters and regrading soil away from the foundation does more against this species than any spray.

Norway rats are a secondary concern. They burrow along the Metra Electric right of way, around vacant parcels near the former factory grounds and at the edges of open land toward Lake Calumet, then forage in the alleys behind the rows. Securely lidded carts, repaired garage slabs and tidy yards help. When burrows appear near a shared fence line, a licensed exterminator can place tamper-resistant stations positioned to protect several attached homes at once, which is usually cheaper for each owner than separate treatments.

Wooden back porches, termites and carpenter ants

Behind the brick facades, many rows have wooden rear porches, stairs and sheds that were rebuilt several times over the decades, often with posts set directly on soil. Eastern subterranean termites, native to northern Illinois, find those posts first and can move from a rotting stair stringer into the sill of the house through mud tubes on the foundation. Swarms of winged termites at a basement window in April or May, discarded wings on a sill and pencil-width mud tubes on stone walls are the warning signs. A licensed specialist can confirm activity and recommend a soil treatment or monitored bait system suited to old masonry foundations.

Carpenter ants follow wet wood rather than soil contact. A gutter that overflows onto a porch roof, a leaking window frame or a rear stair that never dries out can host a colony, and large black ants indoors in March often point to a nest inside the structure. Fixing the moisture source, replacing rotted members with treated lumber on concrete footings and keeping firewood and lumber away from the rows reduce both insects.

Interior row, end unit, block flat or newer home

Housing in the community area is not uniform, and the weak points move with the building type. Interior rowhouses share two walls and draw pests from both directions. End units have more exposed brick and more windows, so they take in more pests from outside. The larger homes and flats have bigger attics and more roof surface for bats and birds. Homes north of 103rd Street and newer townhomes behave like any later construction, with garages and siding rather than shared masonry.

• Interior rowhouse: shared-wall voids, the connected attic and pipe chases behind kitchens and baths.
• End unit: the exposed side wall, window frames and the gap where the stoop meets the brick.
• Larger historic home or flat: the attic, dormers and chimney caps for bats, birds and raccoons.
• Mid-century or newer home north of 103rd Street: garage door seals, utility penetrations and siding transitions.
• Any original basement: floor drains, window wells and damp stone walls.

The Pullman pest calendar

Spring opens with starlings and sparrows nesting in vents and gutters and oriental cockroaches emerging from basement drains as the ground warms. May is when native eastern subterranean termites swarm, and wooden porches, rear stairs and sills in contact with soil are where they appear first. By June, bat maternity colonies are forming in attics, which puts early summer off limits for most bat exclusion. Midsummer also brings yellowjackets to gaps in old brick and under porch steps.

August and September open the window to evict bats once the young can fly, and that is the best time to book roofline sealing. October through December is the peak of mouse season along the rows, often reported by several neighboring households at once. Winter keeps mice active indoors while raccoons and squirrels hunt for warm attic space and test loose chimney caps during cold snaps. A fresh snowfall often reveals tracks that show exactly where an animal is climbing onto a roof.

Prevention that does not harm 1880s masonry

Standard pest-proofing advice can damage a landmark rowhouse, because modern hard sealants and cement patches trap moisture and crack soft brick. Use the steps below, and check with the city's landmarks staff before any exterior change that alters the look of a facade, window or roof. Interior work and small reversible fixes generally raise fewer questions, but the guidance is worth getting first.

• Plug gaps in original brick with copper mesh and removable or lime-compatible materials, not hard cement.
• Fit chimney caps and repair flashing with materials that match the historic profile.
• Screen attic vents and soffit gaps with fine metal mesh only after bats have left for the season.
• Keep basement floor drain traps filled with water and fitted with screens.
• Ask neighbors on the row to seal shared pipe chases at the same time you do.
• Keep garbage in lidded carts and keep the alleys behind the rows clear of debris and old lumber.
• Run a dehumidifier in damp stone basements from late spring through summer.

How professionals work inside a landmark district

A careful provider starts by asking which unit in the row you own and whether neighbors are having the same trouble. The inspection covers the shared walls from your side, the attic and how it connects to adjacent units, and the basement, then moves outside to the roofline, stoop and alley. For bat or bird work, expect a recommendation on timing that follows state wildlife rules and the maternity season.

Exterior exclusion here takes more planning than in most of the city. Visible changes to historic facades, rooflines and windows in a Chicago Landmark district generally need permit approval, so many specialists favor discreet, reversible methods such as mesh, one-way bat valves and matching caps. Owners in connected rows get the best results by booking at the same time, and some blocks have arranged group visits so a single technician can trace mouse runways through several homes in one day.