Attic Truss Bottom Chord

Change the bottom chord depth to match your floor structure depth for floor 2.

Attic truss bottom chord.

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. Those trusses were engineered with a heavy critical dependency on the bottom chords which are in tension. On the general panel of the roof truss specification dialog. 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.

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. A triangle is the simplest form of a truss and the bottom chord is the base piece. Truss capacity is listed by pounds per square foot based on the following load rating criteria. Check the box beside force truss rebuild.

Check the box beside attic truss. The horizontal beam of the triangle of a bottom chord is used in this simple triangle truss construction. 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.

In this case 11 7 8 will be used. The bottom chord therefore carries combined stress of both tension and bending of the truss. The roof system is basically a hinge now. The bottom chord is increased and loaded for live loads similar to floor systems in residential spaces.