How Do Attic Trusses Work

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.

How do attic trusses work. 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. While almost all trusses are made in a factory and trucked in site built trusses also are a possibility. Do you need a crane to set attic trusses. The rooms in the attic trusses depend on the length of the truss and the pitch or steepness of the roof.

The longer the truss and the steeper the roof pitch the larger the room. A framing square will create the series of parallel lines and perpendicular lines if you simply slide it along one of the edges of the rafter. It s safer to use a crane for all involved. These trusses went up in about four hours.

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. Attic conversions are now possible by replacing the truss rafters with a shaped trusses or horizontal beams which in return create additional space. The trusses are fist stacked on top of the walls either by hand or with a crane. They are on 24 inch centers.

Note that a framing square has two legs. All trusses in a roof structure are designed for the worst possible combination of dead live and wind loads. 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. 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.

Once the trusses are up the roof is covered in plywood or osb which gives the roof tremendous rigidity. 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. An attic truss is a support feature found in many home or building attics.

Pitch this is the incline of the roof expressed as a fraction. The narrow one that is 16 inches long is the tongue. The trusses are tied to the walls with small metal plates. Yes you ll need a crane because a typical attic truss weighs well over 100 pounds.

Trusses like all structures are devices for transferring loads from where you don t want them to where you do.