Tuesday, 10 May 2016

Internal Swift boxes in a difficult situation

We have had external Swift boxes on our 17th century house since 2004, with 9 pairs in 2015. Being a listed building, the scope for internal boxes is limited, with just one possible location at the top of a gable end which was built about 50 years ago to replace what was a wooden dairy. 

by Dick Newell

There is no possibility of access to the roof space behind the gable. However a test hole showed that there was a cavity 100mm wide behind Dutch bricks 110mm wide. So, I reckoned we could fit a nest box spanning the cavity and 8cm of the outer wall, giving a floor area of 18cm by 25cm - big enough for a Swift box.

The wall is constructed of nicely selected reclaimed bricks of many textures and colours, so the challenge was how to produce forged brick entrance pieces which look the same.

I eventually took the plunge and we removed one brick from high up in the gable and cast a whole brick insert, 3cm thick out of white cement. A nest box was assembled in the cavity, ship-in-bottle fashion, out of cement fibre-board and glue. This is another variant of the Cambridge Swift Box System.

The internal length of the nesting chamber is 30cm in the cavity and 25cm in the outer wall. The head room is 14cm in the cavity and 7cm in the outer wall.

The first box we deemed a success, so 2 more bricks were removed and 2 more inserts were used, one made of a mixture of white and grey cement and the other the same, coated in crushed red-brick .

The 3 inserts looked a little different from the bricks around them, but with a judicious use of a used tea bag, coffee spread with a finger, and cement powder dotted liberally over the surface, a very good match was achieved.

If the Swifts like these first 3 nest boxes, then there is scope for at least another 2 boxes.

Much of the credit for this goes to Bill Murrells and his remarkable brick laying skills.
Old Beach Farm, Landbeach with 3 internal nestboxes at the top of the near gable
Close up of 3 entrances with forged bricks coloured to match the existing brickwork.
Note the tweeter below the alarm box
3 cast brick entrance inserts.
Components of the fibre-board box before assembly in the wall.
The overall internal length in the cavity is 30cm.
The first nest box completed, and the second brick removed ready for assembling the nest box.
The colour of the first box was a little too white, but tea bags and coffee toned it down.
UPDATE July 21st 2016 - the first Swift occupies one of the boxes.  The wire leads to a small tweeter poked in through the entrance:


#inserts
#Cambridge

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