Attic Truss Bottom Chord

Truss capacity is listed by pounds per square foot based on the following load rating criteria.

Attic truss bottom chord.

Attic trusses are popular over garages or anywhere people want to increase living or storage space without adding another floor to their structure. Room in attic trusses or more commonly attic trusses allow for living spaces within a truss. Top chord live load snow and other temporary loads top chord dead load roofing materials weight of the truss itself other permanent items attached to the roof bottom chord live load storage or living space and bottom chord dead load. The bottom chord therefore carries combined stress of both tension and bending of the truss.

About the bottom chord. Check the box beside attic truss. Those trusses were engineered with a heavy critical dependency on the bottom chords which are in tension. A triangle is the simplest form of a truss and the bottom chord is the base piece.

Factors that determine the size of the bottom chord include on center spacing dead loads applied to the truss span and if there is any pitch applied to the bottom chord. In this case 11 7 8 will be used. The bottom chord is increased and loaded for live loads similar to floor systems in residential spaces. For traditionally spaced trusses the bottom chord is cut out of 2x4 or 2x6 dimension lumber but can also be cut out of 2x8 2x10 2x12 and even lvl material for roof trusses.

Change the bottom chord depth to match your floor structure depth for floor 2. On the general panel of the roof truss specification dialog. Check the box beside force truss rebuild. Select the roof truss and click the open object edit button.