Framing A Pentagon Roof

Plan first cut rafters then assemble the base.

Framing a pentagon roof.

If the unit of rise in inches is 3 then the cut is the unit of rise and the unit of run 12 inches or 3 12. A hip roof design refers to a roof where the roof sides slope downwards from a middle peak with the rafter ends meeting the exterior walls of the house. The rafters on the roof side of the turret are cut flush with the plate. The slate roof which did its job protecting the building from water actually.

Then the tongue will give the direction of one side of the triangle. 6 159 on the tongue and 10 on the body to draw out the plumb and level cuts of the octagon hip rafter. Each of the four sides of the roof slope downward there are no upright or vertical parts no gables etc on a hip roof. And the line length measurement from the roof peak to the building wall is the hypotenuse.

The slate roof was nailed to a wood sheathing that covered concrete at a 23 degree slope. When flight 77 hit the pentagon on september 11 2001 it dumped jet fuel on the roof that then ignited. Place the square so that 12 inches an the tongue and 20 79 inches on the body are over the line a b. The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle.

Using the chappell master framing square line 1 under 8 12 6159. Line length is the hyptenuse of the triangle whose. Apothem multiplier can be used to find the hip rafter run of the polygon if you know the common rafter run. Then i start building the base.

You would use the pitch of the polygon roof on the tongue of the framing square and the hip run per foot on the blade of the framing square to layout the plumb and level cuts for the polygon hip rafter. 1 8 pitch is given so 24 x 1 8 equals 3 or unit of rise in inches. The rise or height of the roof at its peak is the altitude of the triangle. Figure 2 2 roof framing terms.

After drawing the plan and figuring out the various framing lengths and angles i pick the best stock for one common rafter to use as a pattern for the rest. The run or half the building span is the base of the triangle. In this video jerry cole of in line industries shows how simple it can be by building a 5 sided pentagon frame in less than 10 minutes and cuts it to a perfect size the first time. By reversing the square so that the 12 inches is at a and the 20 79 inches is at b the other side of the triangle may be drawn.