I think the weak point will be the seam that joins your walls. That should be taped inside and out, but may still need some reinforcement to prevent buckling under snow or wind load.
Calculating your angles will all be based on 360ºs, so the sum of the angles in any plane of the structure will need to add up to 360. I've only built a hexayurt, but the principle applies to any structure. So for example, if you build a rectangular box, each corner angle = 90º and 4 x90 = 360. For the hexayurt you have two corners where the wall meets the ground @ 90 and two corners where the roof meets the walls @ 60º, so that equals 90 + 90 + 60 + 60 = 300. So the roof peak will be 360 - 300 = 60º. For structural integrity all of these intersections should be beveled, and the bevel cut on each panel where it intersects with another will be half of the intersection, in this case 30º. I cut my bevels with a skil saw because the blade can be angled at 30º. A hexagon will have angles of 60º where the wall panels meet (360 / 6 = 60º). An octagon will have angles of 45º where the wall panels meet (360/ 8 = 45), so your bevel cuts will be half of 45, or 22.5. I built a model out of 3/4" plywood scrap that I sized down to 1' = 1" proportions. This will help you a lot in checking your math before committing to cutting the foam panels. Just cut the plywood and assemble with masking tape. Better to discover any errors in the model stage than to find out later when you're joining panels. Phil On Jan 3, 9:29 pm, kenwinston caine <[email protected]> wrote: > I'm wanting to toss up a quick experimental building to test its > ability to withstand winter snowload and winter-spring winds. > > This is BASED ON the Hexayurt but is not a hex, rather an octo. And > that's where I need help. > > I will be using 4'x8'x2" foam panels. Walls will be eight feet tall > and eight feet wide. Eight of them connected in an octagon. > > Roof panels will be cut diagonally from 8 foam panels of 4'x12'x2". > (Specially fabricated.) (Or, alternately of 4'x16'x2" panels. See > final question below.) > > My questions: > > 1. What angles will I need to cut at the corners of each wall so they > butt together perfectly? > 2. What angles will I need to cut along the lengths of the roof > diagonals so they fit together properly? > 3. What angle will I need to cut along the width of the roof panels > where they butt together with the tops of the walls so they fit flush? > > Since this is a tension structure, I need to get those angles right. > Can someone who really understands this math tell me what those angles > should be? > > Final question: Will 12-foot-long roof panels give me a greater than > 30-degree angle roof pitch when I have a 64-feet-diameter structure? > If not, what would the pitch be if I use16-foot-long panels? And, if > I do that, what angles would I need to cut on their outside edges so > they all fit flush together properly and fit flush against the tops of > the walls? > > Very grateful for the help. > > Hoping to put this up within two weeks if we continue to have 50- > degree days. Need the math calculations ASAP so can pick up the right > quantity of materials and begin cutting. > > Best, > kwc -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hexayurt?hl=en.
