Using Trusses And Rafter Ties In Attic

Determining which truss or rafter is the girder may require a trip into the attic.

Using trusses and rafter ties in attic.

Rafters are a better choice for specialty projects. Instead of attaching the tie to the rafter you will be attaching it to the bottom chord of the truss. Firstly the tributory width d should be 3d as only every third rafter is tied. Best uses for trusses vs.

In a nutshell trusses are right for most projects. In most homes the ceiling joists also serve as the rafter ties. Hurricane ties offer a strong connection that will provide you with the strongest resistance against uplift. Rafter ties are always required unless the roof has a structural self supporting ridge or is built using engineered trusses.

For hip roofs the code specifies that hip and girder rafters or trusses be connected to exterior wall plates. Attic conversions are now possible by replacing the truss rafters with a shaped trusses or horizontal beams which in return create additional space. Installation is the same for trusses as for rafters see above. 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.

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. A lack of rafter ties is a serious structural issue in a conventionally framed roof. Collar ties may take up space in the attic of your home but they are there for a reason. 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. 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. Scissor trusses will provide enough steepness for any vaulted ceilings in the plan consult your architect to determine that.