Hexagon Roof Framing

In this example the octagon segments are 4 ft.

Hexagon roof framing.

Mark and cut an end as shown in diag. Hexagon and octagon roof framing geometry tait chappell told me about the advance timber framing class at fox maple they put on last week where the students built a hexagon 13 5 12 common pitch with two dormers at 22 12 valleys joining into rotated purlin headers. I positioned the cross members to coincide with the plywood roofing pieces. The tangent of 22 5 41421 laying out an octagon using a framing square we would take 12 on the blade and the number to be taken on the tongue is 12 41421 which is 4 97 or nearly 5.

Edited 6 5 2006 9 54 am et by joebartok. If i did this again i would build the roof frame on the ground and lift it into place once all secured together. The central angle for an octagon roof is 45. We have found the value of a which defines a point on the underside of the triangular panel directly under the roof s apex we know that when 2 planks meet at some angle the bevel will be the same right along the edge.

Enter pitch pitch and the plan angle at the eaves 120 for your hexagon and the common rafter span 2 common run in this framing angle calculator. It was difficult to hold all the roof beams in place until i had located them accurately. The structures i have solved to date had backed hips meeting at the center. Some galvanised floor joist hangers came in really handy for attaching the roof to the main body.

First i figure out the framing dimensions with a calculator. Long and combine to create a base width of 9 ft. The unit run for the hip rafters is 13 7 8. So i decided to draw out a similar hexagon plan.

One half of 45 is 22 5. Saw off 10 mm from a side so that it now measures 90mm x 80 mm. This is how i ve worked out the formulae. Start by making a central apex block to make a flat attaching point for every rafter.