Built-in nest space in an outbuilding Instructions for building a narrow Barn Owl nesting or roosting box that doesn’t take up too much room in an un-heated outbuilding or large shed. First make a 130 x 250mm hole that is visible from open countryside. Make the hole as high as possible. The wooden beam below the hole is not needed – it just happened to be there. We wanted to minimise how far the box projected into the interior space of the building… …So we chose the minimum front-to-back size = 400mm, and width 1000mm. Fitting the top. Depth from the bottom of the hole to the bottom of the box is important = 500mm. Fitting the first side. Fitting the second side. Covering small gaps at the top (not essential). We used 12mm softwood FSC plywood and 25x50mm battens. Fitting the floor (1000 mm wide x 400mm front-to-back). Covering any small gaps at the bottom is important. Ready for the back to be fitted. This is the inside of the back… … which incorporates a large inspection panel/door close to the bottom. The three little boxes below are for small hole-nesting birds like House Sparrows. Fitting the back (1000mm wide x 800mm high). A 10mm peep hole is drilled in each side 200mm above floor level. For ease of clearing out, always make the inspection panel/door large. Please don’t call us unless you really need to… … all the information you need is on our website. Good luck(!) and remember… … the creation of good foraging habitat is even more important.