I have been conducting home inspections in Costa Rica during the past 26+ years and I frequently encounter evidence of bats. Some clients are looking for guaranteed solutions to eliminate the bats, because they scurry around in the ceilings at night and make it difficult for the homeowners to sleep.
I have found bat droppings inside and outside homes on walls, floors and terraces.
Additionally, the open gaps under the corrugated roofing laminates that are commonly installed here, make it easy for insects and bats to enter inside the roof cavity and attic. and once inside, they eat and excrete their droppings.
Their droppings can cause diseases and the odor attracts more intruders such as raccoons, pizotes and other mammals searching for food.
Bats are common intruders in Costa Rica, and they are nocturnal, so at night you may hear them scurrying around above your ceilings. Once inside, they are difficult to eradicate and if they die inside your dwelling, the odor will not be pleasant. If a dead bat is found in your home, do not touch it with your bare hands, because bats are associated with a few diseases that affect people, such as rabies and histoplasmosis. Rabies is dangerous, but only about 5% of bats carry the rabies virus.
The most serious health risk is from a disease organism that grows in the nutrient-rich accumulations of bat droppings, called Histoplasmosis, which is caused by a fungus and transmitted to humans by airborne fungus spores.
The incidence of histoplasmosis being transmitted from bat droppings to humans is not high, but fresh bat droppings can contain the histoplasmosis fungus.
Furthermore, the accumulation of bat droppings can harbor parasites that may invade your dwelling. Although these parasites can bite and irritate, they are unlikely to transmit diseases to humans. Some parasites that may cause problems inside dwellings include the bat bug, (related to the bedbug, soft ticks and biting lice.)
There are several methods to prevent bats from entering inside your home, without killing them. I have helped many folks solve bat problems, so they can sleep better at night.
I have seen houses where owners have installed pieces of shiny objects like aluminum foil to deter the bats. There are electronic devices available that emit sounds that bats do not like. There is also a pleasant remedy that you can use, especially on terraces where you and your friends gather. You can use some natural fragrances such as: Cinnamon, Peppermint, Green Tea, Eucalyptus, or Menthol to discourage bats from hanging around your house. The scents irritate the bats and they will go elsewhere. You will need to ensure the scent is strong enough and lasts for several days.
If the bats have entered inside your roof or attic via gaps under roofing, fascias or soffits, the only method that I know that works for sure is to plug the gaps where they enter. The easiest method is to apply an exterior grade caulking product that can be painted to match the exterior color of your house. If the gaps are larger, you can cover them with fiberglass screening that will not rust.
In Costa Rica, the most widely used roofing material is corrugated metal roofing laminates and there are usually gaps under the laminates where bats and other insects or rodents can enter. If you would like to gain acoustic and thermal protection, you can remove the laminates and install fiberglass insulation. I have done this in the past for clients that tried everything else and the insulation was a permanent solution. The insulation plugs up the gaps so the bats cannot enter and it reduces the noise from the rain hitting the metal laminates as well as reduces heat transfer into your ceilings while allowing the roof to dissipate heat.
Additionally, there is a new Polyethylene product manufactured to fill the gaps under the various different profiles of roof laminates. The manufacturer is ProTecho, and the products are available at most of the larger building suppliers.
The writer, Tom Rosenberger has lived and worked in Costa Rica since 1993 and from his travels throughout the country inspecting property and construction he has acquired a wealth of knowledge about living and doing business in Costa Rica. If you have questions or would like to schedule an inspection click here.