Cruck frames use large curved timbers to transfer the weight of the roof directly down to the foot of the posts. Besides being structurally efficient and allowing the wall frames to be lighter, they are also quite beautiful with the arches soaring overhead.
Each pair of cruck blades is usually halved from the same tree, and since the exact curve is undeterminable until they are made, there are usually many decisions about the rest of the timber frame design that have to be made during layout.
In this workshop we will build a small two-bent cruck frame like the one pictured below, first determining how to choose the proper trees in woods and how to halve them to produce the blades. Then, layout will begin, with the curve of the cruck blades determining the "packing pieces" necessary to support the purlins and ridge. Both scribing and square rule layout systems are used.