In publicising this idea, it is in the spirit of encouraging people to do experiments, rather than an idea that should be rolled out extensively, not yet anyway. The idea came out of the success of the air brick liner Swift bricks at St Neots.
|Swift brick with 2 fostered Swifts. Photo Judith Wakelam|
It thus occupies a space of length 1 brick and height 2 courses of brick. We wondered about a brick of height 1 brick - would this be acceptable to Swifts?
So, we built some prototypes out of 5mm thick fibre cement board. These have internal dimensions: width 150mm x length 225mm x height 75mm.
|Swift exploring a Swift brick. Photo Clarke Brunt|
For the experiments, we have not knocked bricks out of any walls yet, but we have installed them under eaves with a simple wooden harness.
The width of these boxes could extend across the cavity, which, in modern houses, may be as much as 100mm, allowing a box width of 200mm. Also the length could be extended to 1.5 bricks ~330mm long. This would fit well in a Flemish bond.
|4 fostered Swift chicks in a Swift brick|
For anyone who would like to have a go at this, please get in touch.
Postscript 2016: 2 of the boxes on one house were occupied by Swifts! The other 4 boxes have been occupied by House Sparrows.