Rafter Calculation Techniques

Rick Arnold demonstrates how to cut and install a hip roof, focusing on common, hip, and jack rafters. The tutorial covers calculating rafter dimensions, marking, cutting, and installation. Key steps include determining the run and pitch, using a framing square, and ensuring accurate cuts for a perfect fit. The video emphasizes understanding roof elements for professional application.

What are the three main components of a hip roof?

• King rafter, valley rafter, common rafter

• Hip rafter, jack rafters, king rafter

• Common rafter, ridge board, jack rafters

• Hip rafter, valley rafter, ridge board

Tags

CCSS.8.G.B.7

What two measurements are needed to calculate the common rafter length?

• Height and width

• Run and pitch

• Depth and slope

• Length and angle

Tags

CCSS.8.G.B.8

How is the run of a common rafter adjusted when a ridge is used?

• Divide by half

• Multiply by two

• Add one inch

• Subtract three-quarters of an inch

What tool is used to transfer rafter calculations onto the rafter stock?

• Protractor

• Level

• Measuring tape

• Framing square

What is the purpose of the bird's mouth cut on a rafter?

• To allow the rafter to sit on the top plate

• To provide a decorative finish

• To reduce the weight of the rafter

• To increase the length of the rafter

Why is the hip rafter typically larger than the common rafters?

• To provide additional support

• To match the aesthetic of the roof

• To reduce material costs

• To simplify installation

What adjustment is made to the framing square for marking hip rafters?

• Change the pitch from 5 inches to 7 inches

• Change the run from 10 inches to 15 inches

• Change the pitch from 6 inches to 8 inches

• Change the run from 12 inches to 17 inches

What is the purpose of the hip drop adjustment?

• To decrease the weight of the rafter

• To increase the length of the rafter

• To ensure the top of the rafter aligns with the roof

• To provide a decorative finish

How are jack rafters different from common rafters?

• They are shorter and connect to the hip rafter

• They are used only for decorative purposes

• They are the same length but have a different angle

• They are longer and connect to the ridge board

Why is it important to create mirror image jack rafters?

• To ensure symmetry on both sides of the hip rafter

• To enhance the aesthetic appeal

• To reduce material waste

• To simplify the cutting process