Swift boxes in an 18th century brick wall

Helen Copperthwaite of Millgate, Aylsham, Norfolk lives in an 18th century maltings, with walls 1.5 bricks thick. (~350mm). At least that's what we thought when we started. She was keen to have Swifts nesting in her gable - so being something new, we decided to have a go at it.

Helen kindly laid on a cherry picker, as it may not have been sensible to work all day on ladders at that height.

Our idea was to remove a header and stretcher from the outer wall, then drill out any brick remaining in the middle producing a cavity 350mm long and 85mm high leaving a half brick between the nesting place and the room inside.

We would then cut a 40mm wide piece off the outer stretcher, replace the header with a Cambridge System half brick entrance piece and we would end up with a very nice internal nest space 350mm x 185mm x 85mm.

Where the wall was 1.5 bricks thick this went very well according to plan:

Stretcher, header and bricks in centre of wall removed

Nest concave inserted - bedded down in mortar

Bill Murrells pointing up the inserted components

Sliced stretcher and entrance piece mortared in.
The mortar will dry to a good match with the old mortar

However, unknown to us, in some parts of the wall, the inner bricks had been removed and replaced by studs (timber) and insulation, so we had a wall  only 1-brick thick (~225mm). However, in the places that we broke through to the insulation there was always a stud against the wall. So we screwed a rectangular piece of plywood to the stud, completely blocking any access to the insulation, leaving a nest space 350mm x 175mm x 85mm, similar to the space above. We think this is a viable solution to any wall that is just 1 brick thick.

The final result was 5 new nest places:

5 new internal boxes embedded in the wall.

To demonstrate the principle of how we fitted boxes in the 1-brick thick parts of the wall, these illustrations might help.

Outside view

Inside view

[UPDATE June 2020 : 3 of the 5 nest chambers are occupied by breeding Swifts!]