Boxed In by Railroad Embankments: Rats, Termites and Mice in Hermosa

A square mile walled by rail embankments

Few community areas are defined by railroads as completely as this one. The Metra Milwaukee District North line forms the eastern edge, the Milwaukee District West line runs along the southern edge near Bloomingdale Avenue, and other rail spurs cut through or skirt the area. Those embankments are long mounds of fill, ballast and brush that almost nobody disturbs. For Norway rats they are ideal: burrows in the slope stay dry, cover is continuous for miles and residential alleys sit a short run away.

Blocks that back onto the tracks, including the streets around Ken-Well Park, which borders the Milwaukee District North line, usually see the earliest and heaviest rat activity. The pattern repeats. Rats travel the right-of-way at night, drop into the nearest alley, burrow under garages and wooden back steps, and feed on whatever carts, compost piles and bird feeders provide. Because the source sits on rail property, one round of baiting on your own lot will not end the problem, and owners who expect a single visit to fix it are usually disappointed.

What does work is a combination held over a full season. Locked, anchored bait stations go along the rear fence and garage. Garages with cracked slabs or gaps under the door need real repairs, not just bait. Alley burrows should be reported to 311 so city crews can bait the public side. Expect a provider to recommend monitoring from spring through fall, with station checks every few weeks, and to name the neighboring garages that are part of the colony's range.

• Smooth, packed paths through grass or gravel leading from the tracks toward your fence.
• Holes under the rear corner of the garage slab or beneath wooden back steps.
• Gnaw marks on cart lids and the bottom edges of wooden fence boards.
• Scratching at night inside a garage wall or under a raised cottage floor.

The frame house on Tripp Avenue, and the thousands like it

In 1893 a carpenter and his wife built a modest wood-frame house at what is now 2156 North Tripp Avenue, and on December 5, 1901 their son Walt Disney was born there. The house is the best-known building in Hermosa, but it is also typical of the area. Rail lines brought the first settlers in the early 1880s, the settlement took the Hermosa name in 1885 so it could get its own post office, and Chicago annexed it in 1889. Workers who held jobs along the tracks built small balloon-frame cottages on narrow lots.

Streetcars followed on Armitage in 1895, Fullerton in 1914 and Belmont in 1917, and the Hermosa Improvement Association, formed in 1912, pushed for the park that became Hermosa Park. Brick two-flats filled the southern blocks, and a 1920s boom built out Kelvyn Park with bungalows. By the late 1920s the area was essentially complete, which is why the median home here dates to about 1919. That layering matters for pests: a single block can hold wood framing near the soil, century-old masonry and a 1920s bungalow, each with different weak points and different pests.

Raised cottages and the gap at the sill line

Many of the original cottages survive, but few look the way they did in 1890. Over the decades owners jacked them up and built a brick or concrete block foundation underneath to create a garden unit, enclosed the rear porch or covered the clapboard with siding. When a frame house was raised onto new masonry, the joint between the old wood sill and the new foundation was rarely perfect. Gaps of half an inch or more are common, hidden behind porches, stairs and shrubs.

House mice, rats, moisture and termites all use that joint. When a provider inspects one of these houses, the sill line deserves a full walk-around with a flashlight, and any gaps should be packed with metal mesh and sealed rather than stuffed with foam. Inside, a finished garden unit may hide framing behind drywall or ceiling tiles, so tell the provider whether the space below is an apartment, a crawlspace or a partial basement when you book. Access to sill plates and foundation walls may mean lifting a ceiling tile or removing a panel, and tenants living below need notice.

Termites and carpenter ants in 1880s framing

Wood-frame cottages from the 1880s and 1890s are where eastern subterranean termites show up most often in this part of the city. These native termites live in the soil and build pencil-width mud tubes to reach wood. They find it easily in cottages whose sill plates sit low, whose rear porches rest on shallow posts or where soil and mulch have crept up against the siding over a century. Swarms of dark, winged termites indoors on a warm day after rain in April or May are the most visible warning, often followed by piles of shed wings on a sill.

Carpenter ants swarm around the same time and are often confused with termites. Look for a narrow, wasp-like waist, bent antennae and forewings that clearly outrun the hindwings. They never eat wood; they hollow out boards that a leaking gutter, window or porch roof has already softened, so finding them is really finding a water problem. A licensed inspector can tell the two apart and find the moisture behind them. For termites, the usual options are a liquid termiticide barrier injected into the soil hugging the foundation, or a set of buried bait cartridges that a technician checks on a schedule. For carpenter ants, the job is tracking down the nest, treating it directly and fixing the leak that invited it.

Kelvyn Park's bungalow district and the shift from wood to masonry

North of Fullerton the housing is steadier brick. The Hermosa Bungalow Historic District, added to the National Register on December 31, 2018, covers blocks roughly between Belmont, Lowell, Diversey and Kolmar and counts nearly 300 contributing bungalows along with a handful of brick apartment buildings and two-flats. Kelvyn Park itself, about 8.5 acres on Wrightwood and the largest park in the community area, anchors the neighborhood with a fieldhouse and mature trees.

In these homes the main concern shifts from wood to masonry. Mortar at the base of walls erodes, wood basement windows warp and old pipe holes through the foundation are rarely sealed well, and house mice use all of them from October on. In the district's apartment buildings and two-flats, German cockroaches move through shared plumbing just as they do in flats elsewhere, so treatment has to cover every unit on a stack. Exclusion on historic bungalows should use steel or copper mesh and color-matched sealant, not foam, so brick and limestone trim stay intact.

The parkway trees on these blocks are old enough to reach most rooflines, and gray and fox squirrels use them to get onto bungalow hip roofs. They chew into painted-over wood soffits, the corners where the gutter hangs from the fascia and the thin mesh behind attic louvers. Dawn scratching overhead in February or late summer is the usual first sign. One-way doors, steel mesh on secondary gaps and trimmed limbs handle it, and the work is easiest in fall before winter nesting.

Two-flats, garden units and the cockroach stack

Brick two-flats line many blocks south of Fullerton and turn up throughout Kelvyn Park, and a good number now have a garden apartment below. Their kitchens stack directly over one another on shared drain and supply lines, which gives German cockroaches a private highway between units. An infestation that starts with one secondhand appliance or a box from a move can reach every floor within a couple of months. The tenant who calls is often the one living closest to the source, not the one who brought the roaches in.

Treating a single unit pushes the insects next door and back again. Lasting work covers every kitchen and bathroom on the stack with gel baits and insect growth regulators, seals the openings where supply and drain pipes cross from one unit to the next, and returns two to three weeks later to catch nymphs that hatched from protected egg capsules. Garden units add oriental cockroaches, the large black species that rises from floor drains after storms, along with millipedes and centipedes. Drain covers, sealed foundation gaps and a dehumidifier handle those far better than spray.

A Hermosa calendar

Rail corridors keep rodent pressure going all year, while insects follow the weather. The old frame cottages warm up and dry out faster than the brick bungalows north of Fullerton, so swarming insects and wall-void wasps often show up on cottage blocks first, and garden units stay damp longest after storms. A wet spring or a warm fall can shift every stage by a few weeks.

• March and April: rats expand burrows from the embankments into garages as the ground thaws.
• April and May: termite and carpenter ant swarms in older frame cottages on warm days after rain.
• June to August: German cockroaches peak in two-flat kitchens; centipedes and millipedes move into damp garden units.
• September: yellowjackets build up in cottage wall voids, and summer rat litters spread into new alleys.
• October and November: house mice enter bungalow basements and two-flat first floors.
• December to February: rats concentrate in garages and near warm foundations, making winter a good time to seal garages.

One checklist for three kinds of buildings

Because the housing here mixes wood, brick and later additions, a good prevention plan addresses all three. The items below are arranged so the owner of an old frame cottage, a two-flat landlord and a bungalow owner can each pick out what fits. Most of the work is about soil, water and gaps, and most of it is best done before the spring swarm season or the fall mouse push.

• Pull soil and mulch back so at least six inches of foundation shows below cottage siding.
• Set porch posts and wooden steps on concrete footings instead of bare soil.
• Keep gutters and downspouts working so water does not soak sill plates and porch roofs.
• Pack and seal the sill-line gap on raised cottages with metal mesh.
• Seal plumbing gaps under sinks and behind stoves in every unit of a two-flat.
• Have crumbling joints in the lowest courses of bungalow brick repointed, and screen or replace warped basement sashes.
• Close gaps under garage doors and patch slab corners, especially on blocks along the tracks.
• Keep cart lids shut and report alley burrows to 311.

Scheduling termite, rodent and roach work here

For rodent work on blocks along the rail lines, expect the technician to check the alley side and your neighbors' garage walls, not just your house, and to explain how far the colony's range extends. Bait stations must be locked and secured, which matters on blocks with children and pets. A rat or mouse problem inside an occupied unit can often be seen the same day when a technician is available.

Termite inspections and building-wide cockroach programs are usually scheduled a few days out. A termite visit needs access to the foundation, sill plates, porches and any crawlspace or garden unit, so clear storage away from basement walls before the inspector arrives. For roaches in a two-flat, the owner should arrange access to every unit on the stack so the building is treated at once, then a second visit roughly two to three weeks on. Buyers looking at a cottage here should consider a wood-destroying insect inspection before closing.