A hip 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. A jack rafter is a shortened com- mon rafter that may be framed to a hip rafter, a valley rafter, or both. Thus, there are hip jack rafters and valley jack rafters.
What is hip and valley roof?
A hip & valley roof is simply a modified or extended hip roof. The shape and pitch of the surfaces are basically the same, however the base shape changes from a simple rectangle to a ‘T’ or ‘L’ shape, on plan.
What is the difference between a hip Jack Rafter and a common rafter?
COMMON RAFTER: A rafter that runs perpendicular (90°) from the wall plate to the roof ridge when looking straight down at the roof. … HIP JACK RAFTER: A rafter that runs from the top of the wall plate to a hip rafter at 90° to the wall plate (see Figures 1, 8 and 14).
What is a valley rafter?
: the rafter running from the wall plate to the ridge and along the valley of a valley roof.
How is hip and valley roof calculated?
Hip and Valley Factor Formula
For a roof slope expressed as “X-in-12” (rise-in-run), the hip and valley factor is determined by finding the square root of ((rise/run)² + 2) for the slope of the adjacent roof sections. Divide the rise by the run (the run is 12). Square the result.
Does a hip roof need ceiling joists?
The sheathing & top plates hold the corners together. The thrust to worry about is at the tails of the common rafters. If you build a square hip roof, you can do it without ceiling joists.
Can a hip roof have different pitches?
For example, in an equal hip roof with an 8 / 12 pitch, the pitch of the hip rafter would be 8 / 17. But here it will be different, since the hip rafter doesn’t lie at 45 degrees to the commons. The pitch of the unequal hip rafter can be expressed in relation to either the main roof or the secondary roof.
Are hip roofs always 45 degrees?
Hip rafters are nailed at a 45 degree angle to the ridge board down to the four outside corners of the building. Also used to nail the top of the jack rafters. Jack rafters are nailed to the hip and slope down to the exterior walls. They have the same seat and tail cut as a common.
What are the 2 main advantages of roof trusses?
Advantages of Roof Trusses
- Engineered system specific for each job versus “hoping” the carpenter has had proper training.
- Reduced lumber waste, theft, and disposal costs.
- Manufactured in a controlled factory environment.
- Faster completion of the shell, allowing the bank draw to be released quicker.
What are the two main types of roof support systems?
Most Common Types of Roof Trusses
- Gable Trusses. A variety of the trusses shown above fit into the common or gable truss category, including the King Post, Queen Post, Howe, and Double Howe trusses. …
- Hip Truss. …
- Scissor Roof Truss. …
- Attic Truss. …
- Mono Truss. …
- North Light Roof Truss. …
- Flat Truss. …
- Gambrel Truss.
How do you calculate rafter length on a hip roof?
Hip rafters should be measured along the top from the long point of the plumb cut. I will often go ahead and make the plumb cuts on the hip rafter so its easier to measure and mark the seat cut and tail cut. To find the amount to add for the tail just add the run of the overhang minus the thickness of the sub fascia.
What are hip and valley rafters?
Hip and valley roof rafters are load bearing roof members that run at an angle – (usually 45 degrees) to the support walls and also run at a pitch. The difference between the two is a hip is at the top of the rafters that hang on it, and a valley is at the bottom of the rafters that hang on it.
What is the purpose of a roof framing plan?
Using I-joists requires the same basic understanding of rafter layout and roof design. Truss roof framing is cov- ered in Section 17.4. The main purpose of a roof is to protect the house in all types of weather with a minimum of maintenance.