The Suburban Bat House

Specifically designed for Urban and Suburban areas.

I make my living by evicting colonies of bats (very gently of course) from houses in suburban areas. I find that most of my customers truly like bats and many are fascinated with them.. On almost every job I hear – “We like bats, I mean, we realize that they eat mosquitoes and that they are an important part of the environment but we just don’t want them in our house!” Then I am asked the Bat House Question –“We’d like to keep the bats in the area to eat the mosquitoes. What if we put up a bat house? Would that make them stay?”

For years I have told my customers not to bother buying and installing traditional bat houses in our area because the success rate associated with them is so low in our area. I have never been comfortable telling people “No, bats in our area very rarely use traditional bat houses” so I was always researching ways to create a bat house that would actually work in Massachusetts and Rhode Island.

Suburban Bat Colony Research

In an average year I will inspect over 300 houses that are infested with bats. This has given me the opportunity to study and document the ways in which bats enter and exit houses in suburban areas. I have found that most common entry-point and/or landing area on a house is the gable vent. Bats find these vents so attractive because they provide both shade and a constant air-flow from the attic. Bats will land on the blades of these vents and then crawl inside. If the factory bug screen on the inside of the vent is loose or missing the bats will make their way into the attic. If the bug screen on the inside of the vents is intact the bats will not be able to gain access to the attic but they will still roost under the blades and use the vent as an exterior roost as shown in the pictures below. Bats will roost behind these blades of the vent during the daylight hours and leave shortly after dusk to go out and feed on mosquitoes only to return before daylight to repeat the process.

Fact 80-90% of the bat population in suburban areas resides in houses, attics and other man-made structures.

How it started

In July of 2004 I performed a bat removal service at a home in a small sub-division and evicted a few dozen bats that were entering through the gable vents. Two weeks later I got a call from their neighbor that lived two houses down. She now had these bats in her gable vents and also wanted them evicted. Then while I was doing that job I nudged two bats out of the gable vent that I was working on and watched them fly in a big circle and enter the vent in the next house over. I already knew that bats were attracted to gable vents but this job showed me just how much these bats seek them out and are trained to use them.

Theory

If these suburban bats are so determined to roost in gable vents than why not build a bat house that closely resembles one? I began experimenting with different designs and finally settled on a very simple design that closely resembles a gable vent. I have since installed the Suburban bat house in a variety of different situations. In houses that already had a history of bats I had 100% success. The bat houses were used by bats in a matter of days.

When installed correctly, the Urban Bat House out-performed the traditional bat house in Suburban areas 10-1. I attribute this to the gable-vent design of this bat house and the fact that bats in suburban areas are trained to use gable vents. The Suburban Bat House also has one critical component that no other bat house has:Air-Flow This bat house uses the constant air-flow from the attic to attract bats and keep them coming back.

Fact – Traditional bat houses in Massachusetts and Rhode Island have less than a 5% success rate in attracting bats. They do however have a great success rate at attracting wasps and hornets!

Air Circulation

The reason that gable vents are installed is to allow houses and attics to breath. Air enters in the soffits below the gutters and rises through the attic and exits through the gable vents. Air flow is the main factor that attracts bats to gable vents. Bats can sit in these vents and have air constantly moving over them. Traditional bat houses are simply wooden boxes and have no ventilation and no air flow whatsoever. This is why bats prefer to roost in gable vents over bat houses or anywhere else for that matter.

In many cases I have evicted groups of bats from a gable vents and installed a traditional bat house in close proximity to the secured gable vent (as pictured above) in an effort to get the bats to inhabit the bat house. Every time I have been disappointed when I returned weeks later to find no activity at all in the traditional bat house. Why? Because traditional bat houses do not have air-flow.

Suburban Bat House Design

The idea behind this bat house is rather simple- Install a gable-vent with a roomy, well-ventilated chamber for bats OVER the existing gable-vent that the bats are already using (or will be soon be using when they locate it). When the bats return to the gable-vent they will hardly even notice the difference. The bats will continue to inhabit the bat house but are not able to get into the attic. You get all the benefits of having bats in your yard without worrying about the getting into your attic. The pictures below illustrate the design of the Suburban Bat House.

How bats use the Suburban Bat House

Below is a short video summary that describes how bats use the Suburban Bat House.

Suburban Bat House Video

You can expect to see bats residing in these types bat houses from late April until mid-October depending on the daytime temperatures.

Will the bats get into my attic?

No. The screening on the inside of the bat house prevents bats from getting into the attic. The bat house is designed so that the bat droppings will fall out of the gable vent and not into your attic.

Why install the bat house over the gable vent? Why not just mount it on a pole or screw it to the side of the house?

There are many benefits to installing the bat house in this area:

• Air-Flow– By installing the bat house over your gable-vent your provide bats with a constant air-flow from the attic. Lack of air-flow is the reason that 95% of traditional bat houses fail.
• Performance– If bats were using your existing gable-vent to enter your attic or just as an exterior roost you should have close to a 100% success rate for getting bats to use your Suburban Bat House.
• Almost Invisible– Once installed and painted to match the house the Suburban Bat House is almost invisible. It only sticks out 5 inches from the side of the house.
• Easy Installation– It takes a little bit of carpentry skills to install the Suburban Bat House correctly but it is much easier than erecting a 20-foot steel mounting pole in the middle of your yard for a traditional bat-house.
• Low-Maintenance– The Suburban Bat House requires very little maintenance. A quick trip up a ladder to clean out any bee/wasp nest each year is all that it needs.

**Installing the Suburban bat house over an existing gable vent will not restrict the ventilation of the attic in any way.**

Ordering/Purchasing Information

By now you’re probably thinking “Great, but how much does it cost?”

They’re free. No really. I am not selling them. Instead I am posting these plans here on BatGuys.com for anyone to use for free. Anyone with some basic Carpentry skills should be able to build and install one of these bat houses relatively easily. I am providing these plans because I would love to see homeowners use this design to provide Suburban bat colonies with places to roost. All I ask in return is that you take some pictures of your installed bat house and send them to me.

I would love to build a few hundred of these houses and install one at every bat removal and exclusion project that I perform but I just don’t have the time to build them. During the summer months we are inundated with calls for bat control and I can’t afford to be building, painting and installing bat houses when I have people calling me screaming because they have bats flying around their living rooms.

Listed on this page you will find step by step instructions on how to build your own Suburban Bat House. Please visit our Suburban Bat House page and our Bat House Disclaimer page if you have not done so already.

Materials List

The materials needed to build a Suburban Bat House are very cheap, common and easy to find. Any decent hardware/lumber store should have everything you need. To build a Suburban Bat House you will need the following Materials:

Gable Vent

1 – Gable Vent. The size of the gable vent will vary from house to house. The most common sized gable vent in Massachusetts and RI is the 16 inch by 20 inch gable vent. This is the size that I will be using for this plan. All measurements listed on this page will only work with this size gable vent. If your vent is a different size you can simply measure the vent and adjust accordingly. Please don’t get discouraged if your gable vent is a different size than is listed here. Keep in mind that the whole idea is to box-off all sides of the gable vent so that it fits over your existing gable vent. You can still use the pictures to see how it is put together and installed.

Wood

There are only 4 pieces of wood needed to build the Suburban Bat House. One piece for the top, one piece for the bottom and one piece for each side.

1 – Six-foot piece of 5-1/2 inch pine.

1 – Six-foot piece of 9- inch pine. (you’ll only use a 21-inch piece but 6 foot is usually the smallest piece you can buy)

Hardware

24-30 – 1 1/2″ inch wood screws. You can also use galvanized drywall screws.

1 – Piece of 1/4″ galvanized screening. You will need a piece large enough to cover your existing gable vent. The gable vent on this page measures 16 inches by 20 inches. Most stores sell small rolls of this material. A 3′ by 5′ roll will be more than enough to cover most vents. Look in the gardening isle of most home and garden stores.

Total Cost of Materials should be between $30 and $40 depending on the size of your gable vent and your geographic location.

Tool List

To construct your Suburban Bat House you will needs the following tools:

Cordless Drill- Any drill over 9-volt will work.

1/8 inch drill bit- To drill holes for screws.

Magnetic Bit holder with Phillips head

or Table-saw or Circular-saw-Four cuts are needed in this project. A table-saw is the optimal choice but a circular-saw in the hands of an experienced person will work also.

Hand Shears- To cut Screening to size.

Once you have everything you need we can begin with the project.

Step 1- Match the Gable Vent

To start we begin with a gable vent. The gable vent that you use to build the bat house MUST be the exact same size as the existing gable vent on the house or it will NOT fit over the existing gable vent. Take measurements and then hold the vent up to the existing vent to make sure it is the same size. The most common sized gable vent in Massachusetts is the 16″ by 20″. That is the size that I will be using for this plan. All measurements listed on this page will only work with this size gable vent. If your vent is a different size you can simply measure the vent and adjust accordingly.

Step 2- Remove Factory Bug Screen from the new Gable Vent

You must remove the cloth bug screen to allow bats to use the entire are between the bat house and the gable vent.

Use a pair of pliers to grab one corner of the screen and then remove as shown above.

Step 3- Screen the Existing Gable Vent

Cut the piece of 1/4″ galvanized screening to fit over the entire gable vent. (the one that is installed on the side of your house)

Step 4- Fasten Screening to Gable Vent

** Please take a quick look inside the vent to make sure that there aren’t any bats inside before you screen it.**

Fasten Screening to gable vent using 6-8 screws as shown above. Be sure to cover the entire vent but do not let the edges of the screen extend beyond the edges of the vent or it will interfere with the installation of the bat house.

Step 5- Cutting the Wood

Both Left and Right- Measure 5 1/2″ wide by 25 inches to the long end of the angle and 20 inches to the short side of the angle.

Top- Measures 9″ wide by 21.5 inches long. You must also make a 1/2″ angle cut on this piece so that it fits flush as shown here.

Bottom- Measures 5 1/2″ wide by 17.5 inches long.

Step 6- Assembly

The assembly of these pieces is rather simple and is outlined in the steps below.

** You must drill pilot holes into the pine in the spots where the screws will enter. If you do not drill these hole out first you will split the pine and ruin the wood.**

Fasten the side left and right side pieces to the side of the gable vent as shown in the picture above. Make sure that the bottom of the pieces are flush with the bottom of the vent and the front of the pieces are flush with the front of the vent as shown in picture.

Fasten the bottom piece as shown in the pictures above.

Fasten the top piece in the same manner. You’ll notice that the top piece is over-sized. You will center this piece onto the bat house leaving an equal amount hanging off each side. When centered there should be a 2-inch overhang on each side of the bat house.

That is it. The assembly of this bat house if very simple. Your Suburban Bat House is complete. We will now move on to the installation.

Step 7- Installation

Once the bat house is completely assembled it is ready to be installed over the gable vent on the side of the house. As mentioned in the disclaimer, working on ladders can be very dangerous. If you are not experienced with working on a ladder I strongly suggest that you do not install this bat house. You should find someone that is experienced with ladders and working up high and let them install it for you.

Drill Pilot Holes

Before you go up the ladder you need to drill 4 holes in the sides of the bat house. Drill one hole on each side in the location shown above. Then drill another hole approximately 3 inches up from the bottom on both sides underneath the first holes. These will be the holes used to secure the bat house to the gable vent.

Mounting the Bat House

You will need four 1 1/2″ screws to secure the bat house to the existing gable vent. Be sure to have them on hand before you go up the ladder.

Once in place you simply push the bat house over the gable vent. If it was built correctly it will fit over the gable vent nice and tight.

** If the bat house does not fit over the gable vent you can remove these screws from the bottom of the bat house to loosen it up. Once that is done you should pull the sides out a bit and then try it again. Once it goes on you can replace the screws that you removed from the bottom of the bat house.**

Securing the Bat House

Push the Bat house hard up against the side of the house to be sure that all sides are flush against the siding. Sink screws through the pilot-holes and into the side of the gable vent as shown in the pictures above. Do this on both sides. You will use 4 screws total.

At this point the bat house has been properly mounted and secured onto the gable vent.

Step 8- Caulking/Waterproofing

** Very Important- You must seal all edges where the bat house meets the siding of the house to prevent leaks!**

Please do not skip this step. If you do not seal the edges with sealant you will have water leaks inside the bat house. Water will deter bats and could possibly cause a leak in your gable vent.

Sealants- Pure silicone is best for keeping water out but it is not paint-able. If you use Silicone you will not be able to paint over the bead of sealant. If you plan on painting the bat house you should use some type of paint-able waterproof caulking.

Caulk all sides of the bat house as shown in the pictures above. Be sure to use a thick, heavy bead on the top to prevent water from getting behind the bat house.

Step 9- Painting

Apply one to two coats of exterior latex primer, then two coats of exterior latex paint to the Bat house. Most people choose to use the same color as the siding of the house. In this case the bat house will all but disappear once it is painted. You can also use the same color as the house’s trim.

Completion!

At this point your Suburban Bat House is complete. You can expect bats to use these houses anytime from Early April through late October depending on the temperature. In warmer years I have seen bats in gable vents in December and January.

If you have any questions about the Suburban Bat House please feel free to email me with any questions at Info@BatGuys.com. Also if you build one of these bat houses I would love to see it. Please take a picture and email it to me.

Matthew Grady
BatGuys Wildlife Services

Questions? Comments? Contact me using the information on our Contact page.

From www.BatGuys.com

Download a printable version of these plans as a .pdf here.

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