Top Seam Welds

The top seam weld is an option for connecting the side laps of adjacent steel deck sheets. The top seam weld is the strongest sidelap connection type and until the PunchLok system  (VSC2) connection, was the only option for high shear diaphragms. Due to the increased installation cost and the time required to install a top seam weld, its use has diminished since the introduction of the PunchLok system.

When sidelaps of the HSB-36 and N-24 roof deck are connected with top seam welds (TSW), the 1-½ in. long weld must engage the top of the inner (male) leg. Minimum E60XX filler metal is required. Clinch the joint before welding to create contact between the male and female laps (See AWS D1.3 or AISI S100 for more info).

Left: Top seam weld installed at a sidelap.
Right:  Side view of top seam weld.
Left: Top seam weld installed at a sidelap. Right: Side view of top seam weld.