Bird Boxes

by Andy Slater

I wanted to make a couple of bird boxes to encourage more birds into our garden but in the end I got a bit carried away with the possibilities... and made six!

Aeroplane Bird Box Abstract Bird BoxLog Cabin Bird Box UFO Bird BoxSwiss Chalet Bird Green Man Bird Box

My starting point was a pack of 10mm polystyrol and, because I enjoy a challenge, I thought I'd try to come up with a design that I could make from a single sheet. However, after a visit to the RSPB website it quickly became apparent that it would not be possible to meet their suggested dimensions using just one sheet. So after some fiddling about, I come up with the following design, which used just TWO sheets:

Sheet 1

Begin by dividing the sheet in half across it's width. If you don't know how to do this, click here.

Now mark a point 140mm from one end of the sheet and draw a line across.

The sheet is now divided into 4. The two smaller pieces form the bottom of the box while the larger pieces form the roof.

A 10mm wide strip (the thickness of the polystyrol sheets) needs to be removed from one of the roof pieces for reasons that will become clear at the assembly stage.

Sheet 2

Step one is to check that the corners of the sheet are square. If you don't know how to do this, click here.

Choose a corner as your starting point. We'll call this point A. Measure 185mm along one edge and mark point B. Now measure 185mm along the edge at right angles A-B and mark point C. Join poin B to point C.

If your corner really was square then line A-B should be 262mm long. Thus the centre will be 131mm along. Mark this point and call it point D.

You now need to find point E to create a line A-E which starts at A, passes through D, and is 185mm long.

The kite shape A-B-E-C is the back of the box. Turn the sheet of polystyrol through 180 degrees and repeat the above to mark out the front of the box.

Note that the centre of the hole for the birds to enter the box should be 35mm down from the apex. Mark this on BOTH pieces because although you will only cut a hole in one of them, the mark on the other is shows where you will fix the box to the wall (more on that later).


As you can see, the first sheet is used in it's entirity while there is a spare section of the second sheet. This can be used to make additional parts such as the wings on my aeroplane design and the nose and brow on my green man. In the case of my chalet and log cabin designs I extended one of the kite shaped into this area to make a 'house shaped' front piece. If you do this you will also need to trim the width of the base panels as these will butt up to the face rather than overlapping it.

Cutting Out

I did most of my cutting out with the Hot Wire Foam Factory Scroll table. You could use the hand-held version but it's easier to keep the cuts square (which aids with assembly) using the table. Either way, a useful tip for cutting straight lines is to use modelling pins to pin a strip of wood to the foam and run the hot wire along the edge.

The hole is most easily cut with the Hot Wire Foam Factory Hot Knife because you don't need to mess about disconnecting and reconnecting wires. However you do it, be sure to check the required dimensions on the RSPB website. Different sizes of holes are required to suit different kinds of birds and it's important to note that if the hole is too big, the birds will not use the box.


Assembly is relatively simple, but there are a few places where you can go wrong so do a dry run before you start with the glue. I used Deluxe Materials Foam-2-Foam glue (which allows time to reposition things) and held the pieces together with modelling pins while the glue dried.

Start by putting the back of the box onto a flat surface and attaching the roof pieced as shown in the image below. Note how they overlap at the top.

With the roof in place, flip the box over and insert the front piece. Note that doing this on a flat surface helps to line up all of the edges.

Finally the base pieces are added. Tuck these neatly under the eaves. This will leave a small gap in the right at the bottom of the box. This is intentional and will permit free drainage of any rain that might get into the box.

Depending on what kind of bracket you'll be using to fix the boxes to the wall, you might want to pop one inside before you complete the assembly. I found that the plates that I used would easily slot through the drainage gap in the base of the box when I was ready to hang them.

Detailing & Painting

As already mentioned, the left over polystyrol from sheet two can be used to make extra details. My Aeroplane Bird Box gives a good indication of how much is spare as I used almost all of it for the body and wings. I also made good use of the Hot Wire Foam Factory engraving tool for things such as the leaves on the green man and the 'stones' on the chimney of the log cabin.

I used Miniature Stone Coating to 'paint' the boxes and I found that Jenny Brushes, that have a foam pad instead of bristles, are the ideal tool for its application. Be warned that the surface of polystyrol sheets is very smooth and must be keyed for the paint to get a good hold on it. I discovered this the hard way because the paint began to peel off mine after a couple of months out in the weather. However, it only peeled off the flat surfaces while staying firmly attached to the cut edges, engraved areas, and areas that had been sanded as part of the process of shaping them. A quick rub with some fine sandpaper is all it takes to key the surface and make sure that the paint stays on.


The boxes can be fixed to a wall with a single screw, but a large washer or similar item (I used picture hanging plates), should be used to 'spread the load' and negate any chance of the screw being ripping through the polystyrol. The washer/plate then 'clamps' the box to the wall.

So what did the birds think?

Birds are pretty wary of anything new and I would have been amazingly fortunate to have any birds use them in the first season of their being available. I am pleased to report that although there are no birds using them yet, the boxes have been on the wall through all of the high winds and heavy rain that we had earlier this year.

A final note:

The RSPB website suggest that be boxes should be cleaned out at the end of the season as it helps to keep the boxes free of parasites. Obviously this requires access to the boxes and although I haven't mentioned it before, this issue is easily resolved:

It's easy to get the boxes on and off the wall as the single screw is accessible via the access hole. Once removed, a hole can be cut in the back of the box (the Hot Wire Foam Factory hot knife is ideal), for removal of the contents. This 'panel' can then be put back into place using a few 'tabs' of sticky tape (duct tape is ideal), before rehanging the box.

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© 2018 Andy Slater - All Rights Reserved.