Their are two types of layout methods for timber framing; square rule and scribe rule. Scribe rule involves full-scale layout and mating each piece together before marking and cutting, a laborious process but useful for irregular timbers. Square rule assumes a perfectly square timber exists inside every timber, and if we take measurements off of this perfect square, we can cut all of our joinery and then assemble it later and it will fit. No test fitting needed… or very little. We’ll be covering square rule layout in this article.