Jack Rafters Hip Roof

Rafter is called for only when framing a hip roof but a valley rafter is needed on both hip and gable roofs whenever roof planes intersect.

Jack rafters hip roof.

The first step is to enter the length of the longest jack rafter. Know that the basic skeleton for the roof has to be erected before any jack rafters can be installed. Depending on the size of the roof most hip roofs will have 4 6 short jack rafters that are spaced out every 20 inches 51 cm between the hip rafters and the king common rafters. All the complicated trigonometry calculations are done for you and there s loads more in there too like diminishing jack measurements and hip rafter lengths and angles as well.

The 7 12 pitch hip roof is framed with 2x6 common and jack rafters on 16 inch centers and with 2x8 hips and ridge. When you create a hip roof in a timber frame there are different types of rafters used. They must must be on the same level. Select the following information by using the drop downs to enter values in feet and inches.

If more are needed then simply start over by entering the last measurement in the longest jack rafter field. A jack rafter is a shortened com mon rafter that may be framed to a hip rafter a valley rafter or both. The hip roof framing calculator returns the value of the main rafter the side rafter the length of the hip the height of the knee wall and the lengths of the jack rafters. I use it with an adjustable stanley quick square and can cut the whole roof on the ground take all the timbers up and assemble the lot in one go.

Use the hip roof calculator for an easier way to get started. Thus there are hip jack rafters and valley jack rafters. The hip rafters in purple form the roofline and extend from the plate to the ridge. Since the jack rafters are at an angle to the hip rafter some compound cutting is required to create their housing into the hip rafter.

Span for the main rafters measure from outside of wall to outside of wall. The jack rafters in turquoise connect from the plate in red to the hip rafter and are of different lengths depending on where on the slope they are placed. Measure the distance between the angled hip rafter and the top of the wall at 20 in 51 cm increments and cut jack rafters to fit.