New Roundhouse: Preparation
The timber frame is comprised of 60 individual parts, ranging from heavy to very heavy. It is built from Larch thinnings, kindly donated to us by Coed Hills Rural Arts Space, and left in their original shape. We thought we'd leave the timber 'in the round' to avoid milling costs, but what we didn't realise was how complicated working with round timber really is.12 posts, 12 floor beams, 12 wall beams, and 24 webs (diagonal bracings to stop the structure from twisting under it's own weight), all had to be jointed together in the correct place and angle. This involves a distressing amount of trigonometry, and general number crunching, which is quite hard considering there isn't a flat, even surface (other than those you make) anywhere. Therefore any measurements to be taken have to be well thought out, in case you forget to account for the degree of curve or taper. The only solution seems to be a keen eye, and a willingness to trust your judgement. Every joint consisted of a mortise and tenon, the mortise being marked and cut first. Each end was drilled out with a 2 1/2 inch hand auger, and the sides were cut by 'nose-diving' a chainsaw.
We then trimmed the tops of the posts to the required height (allowing room for post to rafter joints), with a gentle rise towards both doors. The wood most commonly used for making wattle hurdles is hazel because it grows straight and quickly when properly coppiced and it takes bending very well. We had to use whatever coppice was available which was primarily a mixture of hazel and birch. An important point to remember is to layer the wattle evenly around the whole wall, and do not wattle in sections, for this will seriously weaken the structure.