I`m afraid this page is still under development
There is some information on Cloddiau in the articles section.
Cloddiau. Stonechat, July 1996. A basic look at cloddiau, mainly differing patterns.
Masterclass - Cloddiau. July 1996,The basics of Clawdd construction
Controversy of the cloddiau. Natural Stone Specialist, January 2002
Was the pattern used on 20 miles of new clawdd along the A55 the right one? There are also some photos of cloddiau I have built in the work section