Pipistrelles in bat box

Build a bat box

Activity time:
More than 2 hours
Difficulty level:
Hard
Suitable for:
Balcony/roof, Small garden, Large garden, Medium garden
To help:
Bats

Putting up a bat box gives these night-time creatures somewhere safe to roost, raise their pups and sleep during the day.

Bats are having a tough time finding food to eat, and many of their natural roosting places are being damaged and destroyed.

 

You'll want to keep an eye out for common pipistrelles - they are one of our smallest bats, weighing the same as 10 paperclips and are small enough to fit in a matchbox!

 

You can build and put up a bat box whenever you like,  but we've suggested winter when there are lots of cold, rainy days to fill!

 

If you don't have time or the right tools to make a bat box, why not buy one - or several. Research shows that you're more likely get bats roosting if you have several boxes up near each other.

 

Are you doing this activity as part of your personal plan? Either take a look at your progress or create your own easy-to-follow personal plan to help you give nature a home where you live.

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What you will need

  • Ready-made bat box, or 
  • Untreated rough-sawn wood 15cm wide x 1.1m long x 1.5cm thick or more
  • Ladder
  • Drill
  • Screws
  • Saw
  • Nails
Batbox in garden

Burford bat box and bat attractor seeds

Bat box which provides great insulation, featuring two different-sized chambers and a special native wildflower seed mix to attract insects for bats.

Buy now

Step-by-step guide

How to cut the pieces of rough-sawn, untreated wood for your bat box. It is formed of a back plate, two sides, a front, base and roof. The entrance gap is between the back and base of the box.  Back: 330 mm by 150 mm. 50 mm from the top, cut a groove right across that’s 3 mm deep and 28 mm wide. This piece must have a roughened surface so that the bats can grip. Two sides: 150 mm wide, with one side 200 mm high and the opposite side 140 mm high. . This means that the roof will slope down towards the front. Front: 150 mm by 140 mm. Base: 150 mm by 90 mm. Roof: 150 mm by 200 mm. Nail or screw the side, back, front and base together to make a draught-proof finish. Make sure there is a slit 15 to 20 mm wide between the base of the box and the back, to allow the bats in and out. Press the roof into the top groove in the back plate for a tight fit. Screw the lid down to prevent people looking into the box and disturbing the bats.

  1. The basic principles of a bat box. They should:
    • be made from untreated wood, ie wood which has not been pressure-treated with chemicals. Bats are sensitive to smells and preservative chemicals may be harmful to them
    • be made from rough-sawn wood (rather than smooth, planed wood)
    • have good, tight joints  bats hate a draught
    • have a narrow slit at the back of the box, with a rough piece of wood leading up to it that they can clamber up.
    • The very best bat box is one with two or more internal compartments, and one that is as large as possible  a deep cavern makes bats feel really safe, and keeps the air temperature more constant.

  2. Make sure you have the right wood. To make your own bat box, get hold of some untreated, rough-sawn wood.That can be easier said than done! You will probably need to go to a sawyard rather than a timber merchant, as you’re  unlikely to find it at a DIY store.

    Make sure you look for the Forest Stewardship Council (FSC) logo. 

    If your wood feels too smooth, roughen it by dragging the teeth of a saw across the surface  this helps bats get a good grip as they clamber around their new home.

  3. Building your bat box. You'll need a sheet of timber 15cm wide by at least 1.1m long, as thick as possible to keep the bats insulated from too much cold and heat inside (ideally 1.5cm or more).

    Note: the dimensions shown are for 20mm thick wood. If your wood is different to that, the dimensions of the Base should be 150mm by 130mm minus 2 x thickness of the wood, eg if the wood is 18mm thick, the base should be 150mm x 94mm.

    Mark the wood with a pencil, according to the diagram, and then cut it in to the sections.

    Nail all the pieces together as shown in the diagram, making the joints as airtight as possible.
  4. Choose your location. You could put it under the eaves of your house or, if you have a large garden, on the trunk of a mature tree. Ideally, look for a spot that is at least 3m (10 feet) from the ground, sheltered from strong winds and exposed to the sun for part of the day. Position your box so it faces between south-west and south-east. Make sure there is a clear flight line in.
  5. Now put your bat box up. Drill holes at the top and bottom of the box's backing plate and fix the bat box to the wall with screws or plugs. If you’re fixing it to a tree, you can use adjustable ties so you don’t cause any damage to the tree. If you don't have these, use timberscrew bolts.
  6. All bats and their homes are protected by law so it’s important you don’t disturb them. Watch and enjoy from a distance. If you don’t see any bats going in or out, look out for their black droppings underneath the entrance. They’re little dry pellets that crumble to dust. The most likely new residents will be pipistrelles - there are two very similar species which are widespread in villages and towns.

Building a bat box

Find out how to build the best home for bats with this easy video guide.

Build a Bat Box/ Saw/Chisel/Hammer/Secure/Fix/Bat Perfect

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