Hammer-beam roof

I had created one of these structures using Sketchup and mistakenly called it a truss or support. I learned recently that these structures in an open timber roof are called "hammer beam" type roofs. For any would be castle-builder a "great-hall" is probably on the wish list to be built as part of the structure, and having a hammer beam type roof over the room is probably part of the design. Thanks to modern construction techniques one could probably build a roof in such a manner that the components of a hammer beam type roof would not be structural. Try designing a hammer beam type roof and telling the building code department that it's going to hold your roof up. I think you might run into some trouble there unless you're a structural engineer, and even then I'm sure there'd be resistance.

Just my opinion, but I think the better route using modern materials to accomplish a hammer beam type roof in your modern castle would be to use a steel ridge beam supported on either end of the room by steel supports. This allows for a very strong structure holding the roof peak up with no worry about sagging. The hammer beam roof trusses could be constructed of lighter wood and/or hollow glued-up components (like a hollow square table leg) and affixed to the roof and walls. It would still likely require stronger roof rafters as the hammer beams would likely be partially suspended from them and thus incur additional expense in the roofing materials, but it would seem to be cheaper than having heavy, solid beams engineered to support the real thing.

The picture is from Buffalo Architecture, more info on hammer beam roofs there, as well as Wikipedia.

(EDIT:Updated links due to changed web address)

Contact from across the pond...

A visitor to the site from Europe stopped by and made a very good point, and something that I should've posted about a while back: The use of steel in construction. When building with ICF, CMUs or even slipform methods, we all think of the need for using steel reinforcement such as re-bar. There are a lot more uses for steel in modern construction though. There are steel framing components, steel floor joists, and even steel ridge beams. The steel ridge beam is pretty fresh in my memory; a friend of mine built his own house in New Hampshire. He needed a roof ridge beam (the part that holds up the crest or peak of the roof that can run the span of the building) that would take a load of around 55 pounds per square foot due to the snow load requirements needed to meet local code. Most ridge beams aren't terribly long, due to load bearing walls below they can be supported at various points along the span and not need to be engineered to a large size, or of a length that would have difficulty supporting the aforementioned weight. Basically, the longer the span, the thicker and stronger the beam must be to support any weight it must bear. His span went the full length of the building with no support except at the ends. He spent weeks on the phone trying to find a company that could supply an engineered wooden beam that would meet the specifications he needed, the closest any company came was over $3000 for a beam that could only support only 53 pounds per square foot. Finally, someone clued him in to the fact that he could use a steel ridge beam. Sure enough, he found a company that within one week was able to engineer and manufacture a steel ridge beam and supports, pre-drilled and delivered, for $1300. The reason this may be beneficial to castle builders may wish to support a long roof span without support beams interrupting the space below, and steel may be a way to make that happen. The visitor also suggested that the steel could be covered with a wood veneer to hide it if it is exposed to view, also an excellent point.

Thanks Mark, good luck with your castle!

(Examples I found on the web: the photo shows what appears to be a 4"x14" wooden ridge beam, the other photo is a steel ridge beam.)