How to Build a Bat House

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Why a Bat House?

I have bats in my belfry. Well, actually, they’re in my barn where I store my lumber and I’d like to get them out. Although my initial research was aimed at getting rid of the bats, I ended up building them a house. Here’s why: I discovered that many of my long-held beliefs about bats were completely wrong.

I was surprised to learn that bats are not blind and can see as well as any animal. They do have radar designed to hunt flying insects at night, but their eyes work just fine. Also, bats are not common carriers of diseases. They do not spread rabies or disease any more than other mammals. Finally, only three of the more than 1300 species of bats feed on blood. Most eat fruit, insects or nectar. Turns out, bats aren’t as bad as I thought!

On the plus side, I learned that bats offer a great many positive benefits to a homeowner with a little property. For starters, most North American bat species eat insects—lots of insects. Some will consume up to their body weight in bugs every night! Think of them as living bug zappers without the annoying noise. They also produce guano (a fancy word for bat droppings). Guano is a potent fertilizer and is actually mined for profit in bat caves in the south.

After all this research, I resolved to build my bats a house instead of remove them. Building a bat house helps you choose where the bats live, so they won’t come into places you don’t want them. I chose to build the basic four-chambered unit featured on the Bat Conservation International website. They have a wealth of information about bats and bat houses. Be sure to check them out.

The Plans

The bat house plan we’re using offers a perfect opportunity to work with youth or large groups. All the parts can be pre-made into a basic kit that’s fun to assemble. It’s a great way to do something positive for the environment (bats are great) and introduce kids to woodworking.

I modified the plans I found on the BCI website slightly, substituting plywood for cedar and eliminating the ventilation slots as they are not needed in the far north where I live. The bat house we present here is designed for the northern tier of the US. Warmer climes may need to add slots for ventilation. Consult the Bat Conservation International website to see what modifications you may need for your part of the country.

download the plans here

Working with Kids

I enlisted the help of my oldest granddaughter, Jadyn, to help me build a couple bat houses. To keep the project approachable and safe for young woodworkers, I developed a system for cutting up plywood sheets into accurately machined project parts without the hazard of a table saw. Even the angled edges are made using a router bit. All you need to build this bat house is a jigsaw, a router, and a couple router bits (See Sources). Jigsaws are relatively safe tools for young adults to handle under skilled adult supervision. You may want an adult doing the routing.

For younger kids, it’s best to have them pick up the project at the assembly stage. Assembly requires nothing more hazardous than a drill. People love the opportunity to build a tangible object that they then can later observe in service. Kids will get a kick out of seeing something live in their project.

Machine the Parts

For tools, all you need is a jigsaw, a router, and a screw gun. That’s it. I will show you how to use these tools to cut and machine the bat house parts without having to muscle huge pieces of plywood around on a table saw.

For a detailed look at how this technique works, check out this video:

  bat-house-clamp-zone

Besides the straight edge, you’ll also need two router bits to make the bat house. A pattern bit is my first choice for this technique. It allows you to align, clamp, and run the router without having to flip everything over. You could use a flush trim bit to make the cuts. These bits have the bearing at the bottom rather than the top. That requires you to set your straight edge, then turn everything over so the bearing can run on the straight edge. Be sure your pattern bit and/or flush trim bit has a 1” cutter length.

You’ll also need a 30-degree bevel cutter. Again, make sure the cutter is large enough to bevel 34” stock.

Layout Bat House Part

First, lay out your part. If possible, use your factory edge as a starting point. The edge must be in very good shape to do this. If it needs to be trimmed, simply lay out your part oversized and trim all four edges.

Rough Cut Plywood

Use a jigsaw to rough cut the part, leaving about 18” outside the line.

Align and Clamp Straight Edge Guide

Align the straight edge with your mark and clamp in place. Clamp the whole assembly to your bench or sawhorses to prevent shifting while you rout.

chuck the pattern bit

Chuck the pattern bit into your router and trim the edges flush to your straight edge.

Pattern Rout Using First Panel as Template

Use the completed partition as a pattern for the other partitions. This technique insures exact duplicate parts. Temporarily secure the partition template to the rough-cut partition with screws or brad nails. Hold the assembly onto your bench or horses with clamps so it won’t shift as you rout.

Rout Bevel On Partitions, Front and Back

After all four edges are routed flush to the template, flip the assembly over and rout the bevel on the top edge of the partition (C) while the two partitions are still together, giving the bearing of the bit something to ride on. This creates an angled edge that matches the roof angle. Set the depth of cut so you’re leaving a sharp on the layer of plywood you’re cutting.

Use a straight edge clamped even with the edge of the plywood to rout the bevel on the first partition you created, the top edge of the back (A), the front (B) and the two roof supports (G) as well as the back edge of the roof (D). For the roof supports, I like to route the bevel on both long edges of a 1 x 4, then rip the 1 x 4 in two with the jigsaw. An uneven edge on the bottom of the roof supports won’t matter to the bats.

marking angles with a protractor

Lay out the two sides on a piece of exterior grade, 34” plywood. Use a protractor to mark the angles at the top of each side.

Rout angle on sides

Rout the angled ends (E) using the same technique you used on the sides; rough cut, and then trim using the straight edge and router.

Drill Access Holes

Drill the two access holes at the top of each partition. This can be done on a drill press or with a hand-held drill. Hole diameter is 1-12”. The holes are located 3-12” down from the top, and 3” in from the edge.

The access holes allow the bats to move from one chamber to another and regulate their temperature. During the day, the chamber closest to the outside where the sun is hitting will be the hottest. On a cloudy day, that might just be the perfect place for the bats. On a hot midsummer day with full sun, the bats will want to retreat to a deeper chamber where the temperature is a little lower.

Assemble the House

Kit PARTS Now your bat house kit is complete and almost ready for assembly. For this part of the job, I enlisted the help of my oldest granddaughter, Jadyn. She’s 10 years old and proved herself a very capable woodworker (with a little help from her grandpa). Roughen the partitions

Rough up all the interior surfaces of the bat house with coarse sandpaper. Jadyn used a 24-grit disc on a hand pad. Make the cuts across the grain. The grooves make it easier for the bats to climb around the house.

Dry Clamp Sides To Partitions

Next, stack the partitions and spacers (F) and dry clamp the two sides to the stack with their back edges up. This ensures the two sides are spaced perfectly before you attach them to the back.

Apply Glue To Back Edge of Sides2 Apply glue to the back edges of each side. Bats dislike any kind of draft, so the glue serves two purposes here: to make the house strong and to seal out any drafts. Be sure to use waterproof glue throughout the house.

Attach Back To Sides

Attach the back to the sides. Be sure the angled ends of the sides and the beveled edge of the partition line up perfectly. We used self-drilling deck screws, and they worked like a charm. No splitting, no pre-drilling.

Once the back is attached, flip the bat house over on its back. Remove the clamps, partitions, and spacers.

Attach Spacers

Attach the roof support and spacers with galvanized brad nails. Make sure the beveled edge of the roof supports line up perfectly with the angled tops of each side. You could use 1” screws if you don’t own a brad nailer.

Apply Glue to Spacers

Apply a bead of glue on the face of the spacers and the roof support.

Screw down first partition

Screw the partition down onto the spacers and the roof support. Continue to build the interior of the house, alternating spacers and partitions. Be sure to keep the beveled top edge of each partition flush with the angled sides. The roof supports are only placed in the front and back chambers.

Attach Bat House Front

Attach the front to the sides with glue and screws to finish the box.

Attach Bat House Roof

Finally, attach the roof to your house with glue and screws.

With the house assembled, all that’s left is a bit of touch-up sanding to relieve the sharp edges before painting.

Finish the House

Prime and Paint

Apply a high-quality outdoor primer to the house. Be sure to seal all the plywood edges, as they are vulnerable to delaminating despite their exterior grade. I also sealed the bottom edges of the partitions inside the house.

Follow up the prime coat with a dark color. For use in the north where I live, a black or very dark brown are required for maximum heat gain during the day. I always thought bats liked it cool, you know, like in a cave, but apparently just the opposite is true. Bats like it hot! Especially when they have little ones in the nursery.

Check the charts on the Bat Conservancy International website for the best color to use in your area.

Apply Roofing Cement

Use roofing cement as an adhesive to hold shingles on the roof. You could install the bat house with nothing but paint on the roof, but it will last longer with shingles.

adding shingles to the roof

Add the shingles to the roof. I used two layers of starter strip I had left over from roofing our house. Now we’re ready to hang the bat house on the barn.

adding a bat house to the side of a barn

I thought it best to have Jadyn’s uncle Ben do the ladder work.

It’s important to choose a good site for your bat house. It should be 15 feet off the ground and away from any trees to avoid predators. A southern exposure for heat is also very important. BCI has lots of great information on properly installing bat houses.

Bathouse on the barn

The bat house is all set and waiting for its new tenants.

I hope you have as much fun building your bat house as Jadyn and I did building ours!

Bathouse & Builders

Sources

Bat Conservation International: www.batcon.org

Router bits


34” Pattern bit #817-393
30-degree chamfer bit #115-574
Woodworkers Supply: www.woodworker.com
(800) 645-9292
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33 Responses to “How to Build a Bat House”

  1. Len

    I love that your getting kids interested in bats but you have one flaw with your build the inside of the bat house shouldn’t be smooth. The bats need something to grip and please do not use mesh or screen( the bats can get stuck to it) The best way to do it is use a router with 1\8 bit and put some grooves in it.

    Reply
  2. Albert

    Ty for your help.I’m going to set the bat house up in south Texas on a larger ranch by a large fishing pond.

    Reply
  3. Maury Wilson

    I had bats in a louver on the gable of my house and while they were not in my house they were a problem there. So, I screened the louver where they could not get back in the louver and I put my bat house over the louver for a couple of years and then during a winter hibernation period I moved them to a tree nearby. I started with eighteen bats now I have nearly one hundred. Mosquitoes become less and less of a problem. I am going to add another bat barn this summer and I will use your plan.

    Reply
  4. Kim

    Great project and directions. It may be my computer, but the images of shingles being installed aren’t there; it’s just the glue application image repeated. I like the details in this project that a lot of other plans leave out.

    Reply
    • Customer Service

      Hello Kim. These images have been updated. Thank you for your patience!
      Sarah
      Woodworkers Guild of America Video Membership

      Reply
    • Customer Service

      Hello Ray,

      Thank you for contacting us.

      This is the only bat house plan that we have.

      If you have any additional questions, please email or call Customer Service.

      Sincerely,

      Sarah
      Craftsy

      Reply
    • Customer Service

      Hey Etienne!

      Thanks for reaching out. You should be able to download this plan with your Premium Membership. Are you logging in before attempting the download?

      If you need further assistance, please chat, email or call us at 1-855-253-0822.

      Happy Woodworking!
      Madeline
      Woodworkers Guild of America Video Membership

      Reply
  5. janicekbuesing

    Love the bat house my son built one in school. Bet it works great. He sold it but no body has ever put it up so I have bats in my house maybe i should go live in the bat house since nobody else is using it. :)

    Reply
  6. Phillip

    Hello all, over the years I’ve come across several friends and family who’ve built nat houses, and I’ve done a bit of research on them just out of general interest.
    A couple of things I’ve found are …
    Bats tend to not like man made/processed materials such as metal/wire, plywood, paints and glues.

    They are however attracted to cedar, hence the reasoning behind using cedar boards rather than plywood.
    If you’ve ever gone into a very old barn in an area that has bats, you’re likely to find them hanging from the roof inside, that is because many old barns had cedar roofs and some were even entirely built using cedar beams and boards. Those old barns were never stained and bats love to hide out in them.

    If you are worried about the bats not having anything easy to grasp onto, you would be doing them a favor first of all to NOT sand the inside, rather leave it rough cut. If you still feel the need to add something for them to grasp, you could incorporate some small diameter ROUGH cedar dowels on the inside in various places.

    Not knocking anyone or their plans, I think this is all a very good thing, just tossing out a bit of what I’ve learned over the years.

    Thanks for your time and by all means have fun with your projects and awesome to share this with the young ones, it is great education about a creature that’s so often misunderstood!

    Reply
    • Don

      Don’t overthink it. I built a bat house out of OSB. 24″ long, 18″ wide and 6″ deep with four panels inside made of rough surfaced soffit plywood. Works wonderfully and has for ten years. Hundreds of bats in it all summer here in North Idaho. Finished it with wood stain.

      Reply
    • Customer Service

      Hi Robin. >From the article:
      “The access holes allow the bats to move from one chamber to another and regulate their temperature. During the day, the chamber closest to the outside where the sun is hitting will be the hottest. On a cloudy day, that might just be the perfect place for the bats. On a hot midsummer day with full sun, the bats will want to retreat to a deeper chamber where the temperature is a little lower.”
      Thanks
      Paul-WWGOA

      Reply
  7. James campbell

    using chicken wire inside so bats have a place to hold onto seems like a good idea

    Reply
  8. Jim

    The title says ” How to build a bat house ” I didn’t see any dimensions, did it miss a page ???? Also, roughing the inside with sand paper is not good for the bats, they will not have enough gripping power. Great project for the young lady.

    Reply
    • Customer Service

      Hi Jim. Thank you for the suggestion on sanding. To download the plans, click on the button that is displayed near the beginning of the article that says “Download the Modified Plan Here”. This should have everything that you need.
      Thanks, Paul-WWGOA

      Reply
  9. Gabriel Cline

    I am a boy scout who is planning to make bat houses. How do I get a plan of this bat house for my project. Thanks.

    Reply
    • Customer Service

      Hi Gabriel. In order to download this plan you need to be a premium member and log in with your username and password. If you have any questions please contact customer service at 1-855-253-0822.
      Sincerely,
      Jean-WWGOA Video Membership

      Reply
  10. Kevin B

    You wont get any bats in that bat house because you failed to either cut grooves or attach mesh to the inside for the bats to hang onto. Even if bats found your box, they wouldn’t be able to get inside of it.

    Reply
    • Keith Phipps

      Bats really don’t need rough surfaces to cling to. They can be seen hanging on the side of houses, barns, and even smooth rocks, such as in a cave. Rough cut lumber May be used but I wouldn’t mess with wire. Try to keep it as close to their natural habitat as possible.

      Reply
    • David A Fischer

      For all those criticizing the plans, this plan was not developed by the author but by a group of leading bat researchers. The plans are entirely sound! Also, please, please don’t put chicken wire in the bat house! Every bat organization that has plans for bat houses will tell you this isn’t good. Even if it’s costed it will deteriorate over time and become potentially harmful to the bat’s.

      Reply
  11. KingJ

    ​After attending a lecture on local bats (micro-bats to be precise) by biologist & bat specialist Dr Lisa Cawthen at a local wildlife sanctuary (in southern Tasmania, where I live) I am making my first bat box. Dr Cawthen told us not to use any glues or paints because they are toxic to the bats.

    Reply
  12. tom

    Two questions. Th above shown boathouse build, how many bats will it hold. And how much mess will they create, if I attach this to my house

    Reply
    • Customer Service

      Hi Tom. I’m not sure how many bats the house will hold, but you’re right to think about the possible mess below wherever you choose to hang the house. I wouldn’t hang it over a sidewalk, but I would be ok with hanging it over a flower bed, or similar.

      Reply
  13. Michael D'Amico

    I am trying to build the “Single-Chamber” Bat House that is on the batcon.org website and want to add PVC coated, 1″ cell chicken wire to the inside surface of the landing area. They sell this coated wire in 25 foot rolls at Home Depot. I plan on attaching the wire to the painted wood with staples at the very ends of the wire (so there won’t be any sharp edges). Has anyone ever tried something like this before? I think the chicken wire like material will be a good anchoring place for the bats.

    Reply
    • Customer Service

      Hi, Michael. I haven’t tried this before, but I believe that your logic is sound.

      Reply
      • Cornelius

        I live in South Africa and was once told to place an old carper inside and on the landing so the bats could hold on to it, too it helps with temperature control

        Reply
    • Murray

      A safer less harmfull material for them to latch on to, and less expensive is to use non-metal window screen which would be softer on their feet. You can even use discarded screen from a repair shop that would be destened for the dump anyway. Just wash it before using.

      Reply
  14. Rodger Stroop

    Love bats,
    Have built a couple bat houses,
    Really like your plan’s for this one
    Thank you so much for sharing , I will too

    Reply