Purlin Prop Hip Roof

A hip rafter extends from the wall plate to the ridge in the angle of a hip roof.

Purlin prop hip roof.

To find the side cuts need some additional. Purlins are placed under rafters in a perpendicular position on edge not flat. When rafter spans are too great a purlin is introduced to break the span by transferring the loads to gable walls or in this case to the hip rafters. But a purlin is applied directly onto the roof rafters running perpendicular between them while a batten is nailed to roof sheathing or applied over an existing roof for installation of a new roof.

The purlins are therefore carrying half of the roof load and yet the load transfer is only through one third of the timber plus the mechanical fixing of one clout nail. Hip rafters are simply called hips and are shown here as brown. The hip connect the hip purlin intersection single circle with the hip run purlin ground intersections triangles. The two words are often used interchangeably and both are long strips usually wood used for the attachment of roofing material.

Hip roofs can be designed over square shaped buildings as well as on rectangular ones. Purlins on a roof frame serve the purpose of preventing rafters from being over spanned and sagging. Crown rafter only found in hipped roofs in which it forms the centre joint between jack rafters. The purlins are supported by vertical or slightly angled bracing.

Purlin side cuts and lip cuts fig. Rotations angles involved with a purlin in compound hip roof system. Rafters are sloped beams that run from the roof s ridge to the eaves. All angles can be found on the chappell universal framing square.

The design of hip roofs can follow triangular sides as well as a combination of triangular and trapezoidal sides. Some hip roof designs follow pyramid shapes whereas others may have more symmetrical structures. Stabilization typically involves installation of a purlin system. Rick arnold frequent contributor to fine homebuilding and the journal of light construction presenter at jlc live the katz roadshow the remodeling show.

Hip rafter in a hip roof these are fixed to the jack rafters. The angles between these two lines and the hip mark the downslope ends of the mortises for the main and adjacent purlins in the side of the hip. If you see sagging rafters recommend stabilization by a qualified contractor.