Membrane The second guard room has had its floor laid, and Al has been hard at work laying breathable membrane over the roof boards. The two little windows on the south side are constructed in a classic Anglo-Saxon style – arches made from straight pieces. After much deliberation, these red clay tiles were chosen. The pitch of the roof is shallow as required by permitted development (to fit eaves height and other restrictions), and these tiles are both low in profile and rated to be waterproof at this pitch. Battens and counter-battens