Pest-Proofing a Delhi Flat: Sealing the Ways In

1. Drains — the main road into a Delhi flat

This is where cockroaches come from in a multi-storey building, and it is why your spotless kitchen still gets them. They travel up the shared soil and waste stack from wherever the building meets the sewer.

• Fit a cover on every floor drain in bathrooms, the kitchen and the balcony. A simple grating with a flap, or a jaali with a closable lid. This one change does more than anything else on this page.
• Keep the traps wet. A dry trap is an open pipe. In a bathroom you rarely use, run the tap for a few seconds weekly.
• Check the gap around the waste pipe where it enters the floor or wall. There is very often a finger-wide void around it, hidden behind the pipe collar.
• Close the kitchen sink drain at night if it has a plug. Overnight is when they move.

Our cockroach control guide covers the treatment side of this.

2. Every pipe and cable that enters the flat

Walk round with a torch and look at every point where something passes through a wall. There is almost always a gap, because nobody has ever been paid to close it.

• Behind the kitchen sink and under the counter — water inlet pipes, the waste, the RO drain line. This cluster is the single most productive place to look.
• The AC pipe penetration. A three-inch hole through an outside wall, usually loosely filled or not at all. Rodents and lizards use it, and so does dust.
• The exhaust fan duct in the kitchen and bathrooms.
• Cable and internet entry points, and the gaps around switchboards on outside walls.
• The gap behind the geyser and around the geyser inlet pipes.

Seal small gaps with silicone or acrylic sealant. For anything a rodent could use, steel wool pushed in first and then sealed over is the standard approach — they will chew through foam and sealant alone, but not steel.

3. Doors, windows and the mesh

• The gap under the main door. Anything over about half a centimetre is a route in for insects and, at the wider end, for a mouse. A door sweep is inexpensive and also keeps out Delhi dust.
• Mosquito mesh on windows is the highest-value one-off purchase in this whole category. It works every year without anyone spraying anything — our mosquito control guide makes the same point about the economics.
• Check the mesh you already have. A tear the size of a coin makes the whole screen decorative. Look at the corners and where the frame meets the runner.
• Balcony doors and grille gates often have a wide floor gap. Worth a brush strip.
• Keep the balcony drain covered too, for the same reason as the bathroom ones.

4. Take away the places they live

Sealing controls entry. This controls whether what does get in decides to stay.

• Cardboard is the problem material. Corrugated cardboard is warm, dark and edible, and cockroaches breed in the flutes. Cardboard cartons stored under the sink, on top of cabinets or in a store room are the commonest harbourage in Delhi flats — break them down and get them out.
• Fix the leaks. Every pest needs water before it needs food. A dripping tap under the sink or a weeping joint behind the WC is a water source, and it is why kitchens and bathrooms are where problems start. See our small repairs tips.
• Clear the gap behind and under the fridge. Warm, dark, and there is always something under there.
• Store dry goods in sealed containers, not opened packets. This is what stops a small ant problem becoming an established one.
• Do not leave pet food out overnight. Bowl down, food up.
• Take the kitchen bin out at night, and keep it lidded.

Our monsoon prevention tips cover the seasonal version, and the AMC guide covers when a contract makes sense despite all of this.