Complex sentence: A simple timber frame made of straight vertical and horizontal pieces with a common rafter roof without purlins, the term box frame is not well defined and has been used for any kind of framing other than cruck framing.
Split into simpler sentences: A simple timber frame made of straight vertical and horizontal pieces with a common rafter roof without purlins. The term box frame is not well defined and has been used for any kind of framing other than cruck framing.