← Projects & Plans · Bird & wildlife boxes · No. 03
Bat House
A crevice bat box from one rough-sawn board: three stepped boards, four risers and a roof, nailed together, with two 20 mm gaps bats crawl into from below. Based on the Kent Bat Group design.
What the levels mean
- Difficulty 1 of 51 · First buildHand saw, straight cuts and screws. About 1–2 hours. Fine for complete beginners and supported learners.
- Difficulty 2 of 52 · BeginnerAdds angle cuts and drilling. Some steps need a helper.
- Difficulty 3 of 53 · ImproverBevels, rip cuts and a power saw, with more parts to keep square. About half a day.
- Difficulty 4 of 54 · ConfidentProper joints like halving and mortise, where measuring accuracy matters. About a day.
- Difficulty 5 of 55 · AdvancedFrames and structures, heavy parts, two people and several days.
Drag to look around. Use the chapters along the bottom to jump between stages.
02 · Real photos
Built in a session.
Try making one with waney edge for more rustic look. See the second picture.
03 · Tools & materials
Everything you need.
Gather it all before you start. Tick things off as you go: the ticks stay on this device.
Tools
Materials & cost
| Item | Per build | You need | Buy | Price | Cost |
|---|---|---|---|---|---|
| Rough-sawn untreated softwood board, 1300 mm needed at 240 × 20 mm (sold as 25 × 250 mm × 3 m)Gadero roughsawn Douglas fir 25 × 250 mm × 3 m, collection price, October 2026. One 3 m board makes two bat houses | 0.5 board | £per board | |||
| Galvanised round wire nails 2.65 × 40 mmScrewfix Easyfix 1 kg pack (about 575 nails), October 2026 | 36 nails | £per pack | |||
| Galvanised angle brackets 50 × 50 × 60 mmToolstation BPC heavy-duty 10-pack, October 2026. Wall plugs and screws depend on your wall | 2 brackets | £per pack | |||
| Exterior screws 4 × 30 mm (brackets to bars)Screwfix Exterior-Tite 200-pack, October 2026 | 4 screws | £per pack | |||
| Total | |||||
A rough guide, not a quote. Prices are typical UK examples checked in October 2026, including VAT and before delivery. They change often and vary between merchants, and timber sizes do too, so check before you buy. Reclaimed or offcut timber can bring the cost close to nothing. Tap any price to change it.
Converted from millimetres and rounded to the nearest 1/16″. This plan is drawn for UK metric timber. US lumber sizes differ (a 1×6 is 5½″ × ¾″), so check widths and thicknesses before you cut.
04 · Cut list
Ten parts from one board.
| Part | Name | Size (mm) | Qty | Notes |
|---|---|---|---|---|
| 01 | Back board | 480 × 200 × 20 | 1 | Inside face stays rough |
| 02 | Middle board | 360 × 200 × 20 | 1 | Bottom sits 120 mm up the back |
| 03 | Front board | 240 × 200 × 20 | 1 | Bottom sits 240 mm up the back |
| 04 | Long riser | 360 × 17 × 20 | 2 | Ripped 17 mm wide, on edge: sets the 20 mm crevice |
| 05 | Short riser | 240 × 17 × 20 | 2 | As 04, between middle and front |
| 06 | Back bar | 240 × 20 × 20 | 2 | Stick out 20 mm each side for the brackets |
| 07 | Roof | 240 × 160 × 20 | 1 | Flush at the back, 40 mm over the front |
Converted from millimetres and rounded to the nearest 1/16″. This plan is drawn for UK metric timber. US lumber sizes differ (a 1×6 is 5½″ × ¾″), so check widths and thicknesses before you cut.
05 · Instructions
Seven steps.
- 1
Cut the roof and back bars
Crosscut 160 mm for the roof (07), then two 20 mm back bars (06).
✋ Helper needed - 2
Rip, then cut the boards
Rip the rest of the board at 200 mm. Crosscut 480 mm, 360 mm and 240 mm for the back (01), middle (02) and front (03).
✋ Helper needed - 3
Make the risers
Rip the 360 mm and 240 mm strips down the middle into 17 mm risers (04, 05). 20 × 20 mm batten works too.
✋ Helper needed - 4
Long risers and middle board
Long risers on edge along the back board, tops level. Middle board on top. Three 40 mm nails per joint.
- 5
Short risers and front board
Short risers on the middle board, then the front board. Two 20 mm crevices, open underneath.
- 6
Back bars and roof
Back bars across the top and bottom, 20 mm out each side. Roof flush at the back, 40 mm over the front.
- 7
Hang it high
Brackets to the bar ends. High on a sheltered wall with some sun and a clear flight path. Once it is up, leave it alone: bats are protected by law.
✋ Helper needed
06 · Learning layer
Why one board is enough.
Every length comes off one 1300 mm board, with a 3 mm saw cut between parts.
160 + 20 + 20 + 480 + 360 + 240 = 1280 mmThe parts laid end to end.1280 mm + 5 × 3 mm = 1295 mmFive 3 mm saw cuts between them still fit in 1300 mm, with 5 mm to trim.200 + 3 + 17 + 3 + 17 = 240 mmThe width: one board and two risers side by side.480 − 360 = 360 − 240 = 120 mmEach board stops 120 mm short of the one behind it, so bats can land and climb in.5 × 20 mm + 20 mm + 40 mm = 160 mmFive 20 mm layers, the back bars and a 40 mm overhang make the roof depth.284 400 ÷ 312 000 = 91%Area of the parts over the area of the board.The maths stays in millimetres: it's how the plan was measured and how it's taught.
07 · Plans
Download the plans.
Easy plan
22 pages · one step per pageBig text, pictures, tick boxes, helper badges, tools and shopping list.
Download ↓Quick plan
2 pagesCutting layout to scale, cut list, the build in six pictures and the materials with prices.
Download ↓Make it with me
Sessions · groups · privateBuild it in a session with tools and timber ready to go.
Ask about a session →Keep making
