Pests in Pre-War Twins and Rowhomes in Upper Darby

Rowhome pest control in Upper Darby: why shared walls matter

Upper Darby is Delaware County's largest municipality, and much of it is built as blocks of attached homes. Census (ACS) estimates put the township's median home build year at 1948, with roughly 43 percent of homes renter-occupied. That combination means old construction, many hands maintaining it, and frequent move-ins and move-outs.

In a detached house, pests have to cross open ground to reach you. In a row, the wall you share with a neighbor is full of the same pipes, wires and gaps that run through yours. A pest problem two doors down can become your problem without anything coming through your front door.

Which rowhome pests travel between units?

Not every pest uses shared walls the same way. These are the ones we find moving between attached homes most often:

• House mice, which follow pipe chases and gaps along the top of foundation walls from basement to basement
• German cockroaches, which ride plumbing and electrical openings between kitchens and bathrooms that sit back to back
• Bed bugs, which crawl through outlet boxes, baseboard gaps and wall voids when one unit is treated and they scatter
• Norway rats, which burrow along rear yards and alleys where trash is stored
• Odorous house ants, which can nest in a shared wall and forage in both homes

Pre-war home pests start in the basement

Older stone and block foundations crumble at the mortar joints, and generations of plumbing work leave holes where old pipes used to run. Basement windows with rotted frames, coal chute openings that were never fully closed, and floor drains without covers all give rodents and roaches a way in.

Many twin and rowhome basements also stay damp. Moisture draws cockroaches, silverfish, centipedes and camel crickets, and it softens wooden sills enough for carpenter ants to move in. Running a dehumidifier and fixing gutter downspouts that dump water against the foundation does as much good as any treatment.

Rear driveways, alleys and porch roofs

Behind many Upper Darby blocks runs a shared driveway or alley with garages tucked under the homes. Those spaces collect trash cans, recycling, leaf piles and stored items, which is exactly what rats want. A gap under a garage door gives them a straight line into the basement.

Up front, connected porch roofs and shared cornices give squirrels and stinging insects a continuous route along the block. Gaps where flashing meets brick or where a neighbor's cornice has rotted can lead into your attic even when your own trim is sound.

How do you treat one home in a row of twenty?

You cannot control the whole block, but you can make your unit the hardest one to enter and coordinate where it counts. The approach we recommend:

1. 1

   Inspect your own unit fully

   Basement, kitchen, bathrooms, attic access and the walls you share, with notes on where activity is heaviest.

2. 2

   Seal what you control

   Fill pipe and wire penetrations, close gaps along the top of the foundation wall, add door sweeps, and screen floor drains.

3. 3

   Treat with the walls in mind

   Use targeted baits and dusts placed in voids and along shared walls instead of broad sprays that push pests next door and back.

4. 4

   Talk to the neighbors

   Ask whether they are seeing the same thing. One conversation can turn two separate fights into one coordinated treatment.

5. 5

   Follow up

   Recheck after a few weeks. Attached homes often need a second visit because pests keep arriving from beyond your walls.

Renting a rowhome: who handles the pests?

With so many Upper Darby homes rented, the question of responsibility comes up constantly. A 1979 Pennsylvania Supreme Court decision, Pugh v. Holmes, established an implied warranty of habitability for residential tenants, and leases on rowhomes frequently assign routine pest work to one side or the other. Infestations that clearly spread through a building, like roaches or bed bugs, often need the owner's involvement because neighboring units must be treated too. This is general information, not legal advice.

For owners of several units, our apartment pest control service is set up for buildings where treating one unit at a time does not work. If bed bugs are part of the picture, see our bed bug treatment page for how inspections of neighboring units fit in.

What should you check in the first week after moving into a rowhome?

With so many Upper Darby homes changing hands or tenants, a move-in is the best moment to find a problem the last occupant left behind. Empty rooms make it easy to see. Spend twenty minutes with a flashlight on these spots before the boxes go in:

Ask the owner or landlord for any treatment history on the unit, and write down what you find with photos and dates. If something turns up, it is far easier to sort out before your furniture is in the way.

• Under the kitchen sink and behind the refrigerator, looking for German cockroach droppings that look like ground pepper and brown smears in cabinet corners.
• Along the top of the basement foundation wall and on the sill, where mouse droppings collect beside the party wall.
• The basement floor drain, to see whether it has a cover and whether the trap holds water.
• The rear basement or garage door, checking for daylight along the bottom and corners.
• Seams and corners of any furniture, carpeting edges or mattresses left behind, for bed bug spotting or shed skins.
• The attic hatch or top-floor closet ceilings, for droppings or insulation pulled loose under the shared roof line.