Purlin construction and mounting system for flat roof structures

A purlin mounting system for use in a flat roof structure comprising:

• a purlin formed from a single metal strip with a plurality of longitudinal bends defining a first flat mounting wall portion, a first upright wall portion extending upwardly from an edge of the first flat mounting wall portion, a first perpendicularly outwardly extending mounting shelf attached to an upper end of the first upright wall portion, a second flat mounting wall portion, a second upright wall portion extending upwardly from an edge of the second flat mounting wall portion parallel to and in abutting engagement with the first upright wall portion, a second perpendicularly outwardly extending mounting shelf attached to an upper end of the second upright wall portion and extending in an opposed direction to the first perpendicularly outwardly extending mounting shelf, and a third upright wall portion extending from and perpendicular to the first mounting shelf and the second mounting shelf;
• and
• the first flat mounting wall portion and the second flat mounting wall portion cooperating to form a flat mounting wall for mounting the purlin on a roof beam, the first upright wall portion and the second upright wall portion being spaced apart adjacent the first flat mounting wall portion and the second flat mounting wall portion defining a vertical mounting channel extending from a lower surface of the flat mounting wall a distance less than the distance of the first and second mounting shelves from the flat mounting wall.

A method of fabricating a purlin for use in a flat roof structure comprising the steps of:

• providing an elongated strip of sheet metal;
• forming the strip into a purlin by bending the strip along a longitudinal direction into a plurality of integral longitudinal elements including a first flat mounting wall portion, a first upright wall portion extending upwardly from an edge of the first flat mounting wall portion, a first perpendicularly outwardly extending mounting shelf attached to an upper end of the first upright wall portion, a second flat mounting wall portion, a second upright wall portion extending upwardly from an edge of the second flat mounting wall portion parallel to and in abutting engagement with the first upright wall portion, a second perpendicularly outwardly extending mounting shelf attached to an upper end of the second upright wall portion and extending in an opposed direction to the first perpendicularly outwardly extending mounting shelf, and a third upright wall portion extending from and perpendicular to the first mounting shelf and the second mounting shelf;
• the steps of forming the first flat mounting wall portion and the second flat mounting wall portion including positioning the first flat mounting wall portion and the second flat mounting wall portion to form a flat mounting wall for mounting the purlin on a roof beam;
• and
• the steps of forming the first upright wall portion and the second upright wall portion including spacing the first upright wall portion and the second upright wall portion apart adjacent the first flat mounting wall portion and the second flat mounting wall portion to define a vertical mounting channel extending from a lower surface of the flat mounting wall a distance less than the distance of the first and second mounting shelves from the flat mounting wall.