This detail shows the junction between a fairly standard timber framed wall, and a flat roof built from engineered timber joists between primary glulam beams, with a large service void above the ceiling level. By extending the wall construction past the level of the main roof structure, a very thin roof edge is achieved (just the 100mm flashing covering the edge of the roofing material, which in this case is a plastic membrane). The rainscreen cladding is built from vertical timber planks, and whilst normally this would require both horizontal and vertical battens behind, in this case only horizontal ones are needed, as there are gaps between the planks to allow water to drain away (to further promote draining away, the tops of the battens would be slightly sloping). To give a rhythm to the cladding, in this example every so often one of the planks is replaced with a projecting timber fin.
An AutoCAD version of this detail can be downloaded at the end of the article.
Source: Professional Architect's drawings