Properly speaking, the term "hammer beam truss" is an oxymoron. To truss means to tie up, so a truss system will tie opposing plates. Old English hammer beam roofs were in the form of a timber braced arch, not a truss. The reductive design of the current American fashion has tranformed the hammer beam roof system into a queen post truss arrangement with the tie cord severed and removed in the center creating a definitely not a truss structure.
