Using Trusses And Rafter Ties In Attic

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.

Using trusses and rafter ties in attic.

Best uses for trusses vs. Attic conversions are now possible by replacing the truss rafters with a shaped trusses or horizontal beams which in return create additional space. Firstly the tributory width d should be 3d as only every third rafter is tied. Scissor trusses will provide enough steepness for any vaulted ceilings in the plan consult your architect to determine that.

In most homes the ceiling joists also serve as the rafter ties. Rafter ties are always required unless the roof has a structural self supporting ridge or is built using engineered trusses. 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. Collar ties may take up space in the attic of your home but they are there for a reason.

A lack of rafter ties is a serious structural issue in a conventionally framed roof. Your home site is easily accessed. 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. Installation is the same for trusses as for rafters see above.

Instead of attaching the tie to the rafter you will be attaching it to the bottom chord of the truss. For hip roofs the code specifies that hip and girder rafters or trusses be connected to exterior wall plates. Hurricane ties offer a strong connection that will provide you with the strongest resistance against uplift. 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.

Rafters are a better choice for specialty projects. In a nutshell trusses are right for most projects. You don t prefer finished attic space.