Como Acabar Com Morcegos Em Telhados

Removing bats from your roof isn't a weekend project. It's a process that requires patience, the right timing, and knowing the law before you do anything else.

I spent three summers dealing with bat colonies in residential attics across São Paulo and Minas Gerais. The first job cost me two days of work because I didn't know what I was doing. I tried sealing entry points too early and ended up with 40 dead bats inside the wall cavity. The smell alone made the homeowner call the city health department on me. Learned that lesson fast. The core problem with como acabar com morcegos em telhados is that most people treat it like a pest control issue. It's not. Bats are protected wildlife in Brazil under IBAMA regulations. You cannot poison them, smoke them out, or seal them in during maternity season. Doing any of that carries fines that start at 5,000 reais and go up from there.

como acabar com morcegos em telhados: the legal and practical approach

The only legitimate method is exclusion. You install one-way exit devices that let bats leave at dusk but prevent re-entry. They come back to the attic overnight, sleep through the day, and leave again in the evening. After about a week to 10 days, the colony is gone. Then you permanently seal every entry point. Here is what that actually looks like on a real roof. First, you do a full inspection at twilight. That is when bats start exiting. You count how many are leaving and map every single opening. In my experience, the number of visible holes is never equal to the number of bats. A typical house with a colony of 30 to 50 bats might have only two or three access points. Those openings are often disguised as gaps around ventilation pipes, loose tiles, or deteriorated soffits. One specific case stands out. A client in Ribeirão Preto called because she heard scratching in her ceiling every night. When I got there, I found maybe six access points visible from the ground. But at dusk, watching the bats fly out, I noticed a pattern. Most were exiting through a single 2-centimeter gap behind a fascia board that was slightly lifted by termite damage. That one gap was handling the majority of the colony. If I had sealed all the obvious holes and missed that one, the bats would have just found another way in and ended up inside the living space.

After mapping all exits, you install the exclusion devices. I use homemade ones made from PVC pipe and hardware cloth. A 4-inch diameter PVC coupling cut in half lengthwise, covered on the open end with ¼-inch mesh, works fine. You attach it over each exit point with construction adhesive and screws. The mesh lets bats squeeze through to get out but collapses behind them so they cannot get back in. Commercial versions exist, but they cost four times as much and do the same thing. Leave the devices in place for 7 to 14 days depending on colony size and weather. Warm nights speed things up. Cold snaps slow them down. During that window, you should not make any noise or disturb the attic. The bats will figure it out and leave on their own schedule. Once you confirm zero activity for three consecutive evenings, you remove the devices and seal everything permanently. I use expanding foam for small gaps and hardware cloth framed with trim boards for larger openings. Foam alone fails within a year because bats can chew through it. Always reinforce with mesh.

There is a critical timing constraint most people miss. In Brazil, maternity season runs roughly from September to February depending on the region. During this period, you cannot perform exclusion if there are flying juveniles in the colony. Young bats cannot fly well enough to follow adults out through one-way devices. If you seal entries during maternity season, the mothers will return to find their dead babies trapped inside. The result is always the same: a toxic mess and a legal violation. Check your local IBAMA guidelines for the exact dates in your state. Some southern states have slightly different windows. Another counter-intuitive thing about bat removal is that ultrasonic repellents and strobe lights do not work. I tested every commercial product available in Brazil over two years. Not one reduced colony size or deterred bats from returning. The science backs this up. Bats navigate using echolocation, but they are not startled by sound frequencies the way rodents are. They simply ignore these devices. Spending money on them is throwing money away. Similarly, mothballs, naphthalene, and essential oil sprays are ineffective and illegal to use indoors around wildlife. The fumes do not penetrate the roosting areas where bats cluster, and the chemicals can harm you and your family before they harm a single bat.

The real downside of exclusion is that it requires you to be present and methodical. You cannot set it and forget it. If you miss even one entry point during the sealing phase, the colony will relocate back into your house within days. I have seen this happen at least five times. The bats are persistent and remember their routes. A gap of ½ inch is enough for an adult bat. A gap of inch is enough for a juvenile. Another honest limitation: if the bats have been in your attic for years, you will likely have guano accumulation. Bat droppings are not just a cleanup issue. They can harbor histoplasmosis spores, a fungal infection that affects the lungs. If guano is deeper than an inch or covers more than 2 square meters, you should hire a professional remediation service. Do not sweep it dry. Do not use a regular vacuum. Wet the area with a bleach solution (1 part bleach to 10 parts water) and let it soak for 30 minutes before careful removal with a shovel and HEPA-rated protective equipment. I learned this the hard way after getting a respiratory infection from a job in Campinas where I skipped the wetting step. If the colony is small, under 15 bats, and you are comfortable working on ladders and in tight spaces, exclusion is a DIY project that costs between 150 and 400 reais in materials. If the colony is larger, the roof is steep, or you are not comfortable with heights, hiring a licensed wildlife exclusion professional is the safer call. Expect to pay between 800 and 2,500 reais depending on the region and complexity. Get written confirmation that they follow IBAMA protocols and provide a warranty on the exclusion devices for at least one year.

The bottom line is that getting rid of bats from your roof requires doing it legally and completely. Partial exclusion is worse than no exclusion because it creates a deeper problem inside your walls. Take the time to find every entry point, respect maternity season, and seal properly. The colony will be gone within two weeks and they will not come back if you did the job right.