Hip roof – How to design an edge rafter?

How to design an edge rafter?

Stage I . Marking the vertical cut and saddle cut for a roof with a slope of = 1/4 (14° or 25% or 0,25)

– you should find the height for each 30 cm length of the run of the edge rafter. Because for everyone 30 cm section of the run of the usual rafter is 1/4 x 600 cm = 600/4 cm = 150 cm : 10 (episodes after 30 cm) = 15 cm, and therefore the height for each 42,5 cm, the length of the run of the edge rafter will be 15 cm. Place the roof angle with points 15 i 42,5 on the upper edge of the edge rafter and mark the vertical cut at point A; The – – – we measure the length of the edge rafter and using the same points of the angle bar (15 i 42,5) we mark the saddle cut at point B.

Step IIFinding the size of the gable eaves
The run of the eaves of the edge rafter is equal to the diagonal run of the ordinary roof rafters.

Etap III.

Determining the recess of the rafters for 42,5 cm of the edge rafter projection

– we use the same points on the angle bar (15 i 42,5) to designate a vertical cut, by inverting the square;

– we cut the corners of the edge rafter at an angle of 45 °, finally finishing the cuts.

We do not cut off the rafter settlement until the fourth stage is completed.

Stage IV.

Adjusting the rafters in the place where they are mounted on the cap

– we measure from the vertical cut backwards 25 mm at an angle of 90 'and we draw a line parallel to it (this line will be the cut line);

– we measure back diagonally 25 mm from the corner of the cap and cut off the corner;

– the size of the cut off will be equal to the amount added to the vertical cut of the edge rafter seating.

Stage V-a.

Shortening of the edge rafter at the top (at the ridge) for double zipper cutout

Stage V-b.

We cut the corner at an angle of 45′, to make a double cut on the zipper