Roof Rafter And Ceiling Joist Framing Section

The following is excerpted from the international code council icc s international building code section on ceiling joist and rafter connections.

Roof rafter and ceiling joist framing section. A joist is a horizontal structural member used in framing to span an open space often between beams that subsequently transfer loads to vertical members. R802 1 5 8 exposure to weather. There are several variables to consider when determining the proper rafter size. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

Section r802 wood roof framing. Joists are the parallel horizontal beams that run across an open space joining opposite walls in a building to support both the ceiling below and the floor above. The framing details required in section r802 apply to roofs having a minimum slope of three units vertical in 12 units horizontal. When incorporated into a floor framing system joists serve to provide stiffness to the subfloor sheathing allowing it to function as a horizontal diaphragm.

In a rafter roof all of these components are required to provide. Roof ceiling framing rafter joists exterior wall nailed to rafter ceiling joists parallel to rafters 2006 irc r802 3 1 in the 2006 edition of the irc the subject of rafter joist connection has been simplified. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. The diagram above depicts the cross section of a typical prescriptive roof consisting of the rafters a ridge board ceiling joists and collar ties.

Additionally be sure to adhere to the specific fastening requirements in the 2018 irc table r802 5 2 for the rafter to rafter tie ceiling joist connections. California residential code matrix adoption table chapter 8 roof ceiling construction. R802 3 1 ceiling joist and rafter connections. R802 3 1 ceiling joist and rafter connections.

27 c and for roof framing. Joists are traditionally made from timber. The roof framing modification factors shall take into consideration the climatological location. This sizing guide for roof rafters will help determine what you need for your small project.

Not shown are the hip and valley rafters needed to tie the roof together where the rafters are framed at an angle to each other. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. The general requirement is for all joist to be connected to rafters at the top of the wall. For example in a roof structure where the ridge height is 9 feet above the top of the support walls the maximum height that a rafter tie can be raised is 3 feet 3 9 1 3.