Using Trusses And Rafter Ties In Attic

The role of the horizontal beam is to tie the truss together and carry the load that would otherwise be sustained by the support and vertical timber also known as the king post.

Using trusses and rafter ties in attic.

Your home site is easily accessed. In a nutshell trusses are right for most projects. In homes with flat ceilings and an attic space the bottoms of opposing rafters should be fastened together with ceiling joists which form rafter ties when rafters have been installed perpendicular to the ceiling joists rafter ties typically rest on top of the ceiling joists. Best uses for trusses vs.

Since l is the half width of the roof the load should be w not w 2 and there are other serious things wrong with this. Firstly the tributory width d should be 3d as only every third rafter is tied. Determining which truss or rafter is the girder may require a trip into the attic. In most homes the ceiling joists also serve as the rafter ties.

Installation is the same for trusses as for rafters see above. Rafter ties are always required unless the roof has a structural self supporting ridge or is built using engineered trusses. You don t prefer finished attic space. Also the un tied rafters push on the wall plates which span between the tied rafter ends bringing in 2 3 of the load on the tie and adding to the bending in the tied rafters.

Attic conversions are now possible by replacing the truss rafters with a shaped trusses or horizontal beams which in return create additional space. For hip roofs the code specifies that hip and girder rafters or trusses be connected to exterior wall plates. Instead of attaching the tie to the rafter you will be attaching it to the bottom chord of the truss. Hurricane ties offer a strong connection that will provide you with the strongest resistance against uplift.

The girder which by definition supports the inboard end of other framing members can be anywhere from 3 to 11 feet back from the corner. In this how it works article managing editor debra judge silber explains the role of collar and rafter ties in the framing of a roof collar ties are necessary to prevent separation of the roof at the ridge due to wind uplift. Rafters are a better choice for specialty projects.