Friday, 2 December 2016

Belfry cabinets without screws

We have recently looked at a belfry in Suffolk where there is no way of attaching nestboxes directly to the church fabric. Normally one can either screw the boxes to wooden louvre frames, or by screws into joints between masonry blocks. Screws into the masonry would require a faculty.

The church in question has flint and lime mortar walls, so it would not be sensible to attempt screws into the walls, even if permission was granted. The louvres do not have a frame adequate for supporting nest boxes. 

So, if this project goes ahead we plan to use a system that was first used in Holy Trinity, Haddenham over 10 years ago. Holy Trinity is on a hill and has slate louvre blades 350mm apart.

The church architect has kindly provided a PDF of this installation, which was approved by the DAC.
Download the PDF to see detail
We thought it worth publishing this now, as there will be many belfries suitable for swift boxes with this particular challenge.

The key idea is that the sides of the openings (the reveals) are lined with 25mm WBP plywood which is braced with 20mm diameter galvanised threaded steel rods fitted with locking nuts and pressure plates. Then the boxes are screwed to the plywood.

Any tapering or unevenness of the reveals can be filled with suitable softwood wedges.

The picture left shows the particular belfry we are considering and some outline computer models of what we might do:

Click on image to enlarge

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