How Do Attic Trusses Work

All trusses in a roof structure are designed for the worst possible combination of dead live and wind loads.

How do attic trusses work. Trusses like all structures are devices for transferring loads from where you don t want them to where you do. The individual truss members are designed to restrain the corresponding forces i e tension or compression or a combination of bending with either the tension or compression force. The roof rises 4 inches in height for every 12 inches it runs horizontally. While almost all trusses are made in a factory and trucked in site built trusses also are a possibility.

Trusses are typically set into place one at a time either by hand or with the help of a crane but in some cases some trusses can be assembled on the ground and lifted into place as a single sub assembly. These trusses went up in about four hours. Because attic trusses require specific conditions to be met before they can be created we ll begin by drawing a simple structure that meets those requirements. Do you need a crane to set attic trusses.

Select build wall straight exterior wallfrom the menu then click and drag to draw a rectangular structure. The narrow one that is 16 inches long is the tongue. An attic truss is a support feature found in many home or building attics. They are on 24 inch centers.

The trusses are tied to the walls with small metal plates. Attic conversions are now possible by replacing the truss rafters with a shaped trusses or horizontal beams which in return create additional space. Yes you ll need a crane because a typical attic truss weighs well over 100 pounds. It s safer to use a crane for all involved.

While pitch and slope are used interchangeably they are not the same span also known as gable width this is based on the total footprint of the house and refers to the distance between two exterior. Select file new planfrom the menu to open a new blank plan. Pitch this is the incline of the roof expressed as a fraction. A roof truss takes the weight of the roof and the snow on the roof if you live in that kind of climate and transfers it out into the load bearing walls of your house.

The rooms in the attic trusses depend on the length of the truss and the pitch or steepness of the roof. This structure will basically hold up the roof of the home or building and help the roof resist lateral stresses from wind snow loads and debris. The trusses are fist stacked on top of the walls either by hand or with a crane. The longer the truss and the steeper the roof pitch the larger the room.

Note that a framing square has two legs.