DIY Multi-Chamber Bat House
Step-by-step guide made from Expedition Northwoods's YouTube video.
Build a multi-chamber wooden bat house to provide a safe habitat for local bat populations. This project uses simple pine boards and features multiple internal slats with grooves to give bats plenty of roosting space.
- Difficulty: intermediate
- Finished size: Approximately 36 inches tall by 12 inches wide.
Safety
- Always use caution and appropriate safety gear, such as safety glasses, when operating power saws.
- Be extremely careful when working on a ladder, especially while lifting and securing the heavy bat house. Ensure the ladder is on stable, level ground.
Must know before you build
- Upgrade to cedar or weather-resistant wood for 10+ year lifespan; pine lasts only a couple.
- No table saw? Score interior slats with a utility knife or attach plastic mesh for bat grip.
- Pre-start nails in side panels; use a scrap spacer for consistent slat gaps during assembly.
- Mount under an eave or near existing bat houses for shelter and increased occupation chances.
- Stagger internal slat heights to provide varied roosting options, appealing to more bats.
Tools
- Miter saw
- Table saw (RYOBI, 10 inch blade)
- Hammer
- Tape measure
- Pencil
- Ladder
Materials
- Pine boards
- Plywood (Weather-treated)
- Nails
Step by step
Step 1: Cut the Frame and Slats
Cut the side panels and all the internal slats to their various lengths using a miter saw.
- Review Side Panels. Review the two 36-inch side panels that have already been cut. These will form the main vertical sides of the bat house.
- Plan Slat Lengths. Plan the lengths for the internal slats. You can stagger the lengths to provide different roosting heights for the bats.
- Cut Internal Slats. Using a miter saw, cut the pine boards into slats of varying lengths (e.g., 34", 30", 28", 26"). The exact lengths aren't critical as long as they are staggered.
- Tip: Staggering the height of the internal slats provides different roosting options for the bats.
Step 2: Cut Gripping Grooves (Kerfing)
Use a table saw to cut shallow horizontal grooves (kerfs) across all internal slats and the back panel to provide a gripping surface for the bats.
- Set Up the Table Saw. Adjust the table saw blade to a very shallow height, just enough to create a small groove for the bats to grip.
- Cut Grooves on Slats and Panels. Run each internal slat, as well as the front and back panels, through the table saw multiple times. Space the grooves roughly an inch apart to create a ladder-like texture on both sides of the boards.
- Tip: Cut grooves on both sides of each internal slat so bats can roost on either side.
- Watch out: Set the table saw blade to a very shallow depth, just enough to create a groove without cutting through the board.
- Tip: Space the grooves about an inch apart. Exact measurements aren't critical, just aim for a consistent, rough texture.
Step 3: Assemble the Box
Nail the back panel to one side, then attach the internal slats, spacing them about an inch apart. Finish by nailing on the second side and the front panel.
- Attach Back Panel to First Side. Lay one side panel down and nail the back panel to it, ensuring it's flush along the back edge.
- Install Internal Slats. Nail the internal slats one by one inside the frame. Use a scrap piece of wood that is 1 to 1 3/4 inches wide as a spacer to maintain consistent gaps between each slat.
- Attach Second Side Panel. Carefully place the second side panel on top of the slats and nail it down, securing it to the end of each slat and the back panel.
- Attach Front Panel. Flip the assembly over and nail the front panel in place. This panel is shorter than the back panel to create a ventilation gap at the top.
- Tip: Use a scrap piece of wood as a spacer to ensure the gap between slats is consistent.
- Tip: Start the nails in the side panel before placing it on the slats to make assembly easier.
Step 4: Attach the Roof
Cut and nail a piece of weather-treated plywood to the top of the box to serve as a roof, creating an overhang to protect the entrance from rain.
- Select and Position Roof Material. Choose a piece of weather-treated plywood for the roof. Position it on top of the box with an overhang on the front and sides.
- Nail the Roof in Place. Secure the roof to the top of the side, front, and back panels with nails.
- Tip: Using weather-treated plywood for the roof adds extra protection.
Step 5: Install the Bat House
After reviewing the completed bat house, install it high on a barn or pole, ideally near an existing bat colony and under an eave for protection.
- Prepare for Installation. Review the finished bat house. The video discusses placement strategy, choosing a spot on the barn near an existing, smaller bat house to encourage occupation.
- Mount the Bat House. Use a ladder to position the bat house high on the wall, under the eave for protection from the rain and sun. Secure it firmly to the barn wall with several nails.
- Tip: Placing the new bat house near an existing, populated one increases the chances of it being occupied.
- Tip: Mounting the house under an eave provides extra shelter from rain and sun.
- Watch out: Be careful when working on a ladder, especially while handling a large object like the bat house.