![]() This is a very good way of getting an overhang. A secondary rafter is affixed to the primary ones at a slightly shallower angle and fastened to the end of the tie beam, extending below it a ways. The primary rafters are seated into the tie. Put the tie beams on top of the plate and extend them out past it maybe a foot. ![]() Or bring the kingpost all the way to the tie beam.Īn effective way to get an overhang is to rearrange the whole assembly. That is, keep the collar beam up there but add a kingpost between the rafters that pulls up on it. ![]() If it is too wide for this to work, you can add a raised kingpost. If the building isn't too wide, you can just tie the rafter pairs with a collar beam located about the top third point. If you WANT to use a dragon beam, use the seated rafter roof. The purpose of a rafter seat is to support the rafters. Re: Simple Dragon Beam/Corner Tie Questionįirst, the purpose of a true ridge beam is to hang the rafters. It would be nice to know the size and proportions of the structure, the framing of the walls, etc. It is difficult to give any specific recommendations based on what you've given. specifically looking at some forms of roof framing outside of the standard American truss and purlin framing conventions. Right now I'm working on a small bit on roof framing. If you choose a standing roof, with seated rafters, the dragon is not strictly necessary either, it is one of many solutions to this part of the frame. If you choose the ridge beam assembly with hung rafters, the dragon doesn't serve any purpose and is unnecessary. If your rafters are seated firmly into the plate, there are better approaches to use than a structural ridge (namely purlins located at about the top third point) If you have a ridge beam and seated rafters, you actually introduce competing forces into the roof structure that really complicate the engineering. I you have a ridge beam, your rafters are best arranged hung over the ridge and projected OVER the plate, not seated into it. This is an oft misunderstood aspect of ridge beam roof. The use of a ridge necessitates interior supports of some kind. Here's another bit of info that might change some minds about whether to use a dragon beam at all: that 8x4 hip rafter is going to be supported at the top by a hefty ridge beam, which will reduce the thrust at the plate which the Dragon and Cross is designed to mitigate, right?Ĭoncerning the use of a dragon in conjunction with a structural ridge:Īs said, the ridge needs direct support, either posted directly to the foundation or posted to the roof cross beam which is in turn supported to the foundation. I'm still interested in hearing as many opinions as there are out there, so keep them coming! But realizing that my intuition, where building big things out of wood is concerned, was about as reliable as my intuition concerning other things about which I know squat, I decided it would be a good idea to ask the guys who know (that would be y'all). It seemed intuitively correct that keeping the hip, dragon, and cross normal to each other was optimal for what the assembly was designed to do. That's the way that I originally designed the joint after Jim advised that a dragon-and-cross might be appropriate for a tall-ish hip roof. I'm glad to see that option 3 is the favorite so far. I'm relieved that everyone's answer wasn't "why would anyone do that in the first place?" Here's pictures to illustrate (all images are looking straight down on top of the joint): If you could follow all that crap, you're a genius. ![]() 1) Does one leave the cross at 45 degrees to the plate /tie and the dragon at 90 degrees to the cross, such that the hip rafter and dragon are in different planes? 2) Or does one adjust the angle of the dragon to match the angle of the hip rafter (so that the dragon and rafter are in the same plane) while leaving the cross at 45 to the plate/tie? 3) Or does one adjust the dragon to match the angle of the hip rafter while also adjusting the cross so that the dragon-and-cross are at right angles, but the cross is not at 45 to the plate/tie? Which brings me to the quandry I'm currently in I'm left with 3 options for constructing the dragon-and-cross. I, feeling the need to make my project as difficult as possible, want to use dragon beams on a square frame whose hip rafters don't meet at the peak, which means that the bottom end of those rafters will come into the corners at something other than 45 degrees. This makes it easy to create the cross at 45 degrees to the plate and tie, and the dragon at 90 degrees to the cross, putting the hip in the same plane as the dragon. ![]() I've seen several references to dragon beams and dragon-and-cross assemblies now, but they've all been cases in which the rafter is coming into the assembly at a 45 degree angle essentially, the building is square and the 4 corner hip rafters meet in the roof center. ![]()
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