Lapped Purlin Run
A run of steel zed purlins lapped continuously over the roof frames, bolted to cleats at every support and braced by bridging rods between the lines. Bays along the run and the bay span, Lap share of the span, Rafter length and the largest line spacing, Purlin depth and thickness, Cleat width and bridging rows
Details
Category: Roof Framing › Steel Purlins › Lapped Purlin Runs
By Huu Khanh Nguyen · Updated November 4, 2026
Parameters
| Name | Default | Unit |
|---|---|---|
| Bays | 6 | |
| Bay Span | 6000 | mm |
| Lap Share Of Span | 0.15 | |
| Rafter Length | 3600 | mm |
| Largest Line Spacing | 1200 | mm |
| Purlin Depth | 152 | mm |
| Purlin Thickness | 1.9 | mm |
| Cleat Width | 75 | mm |
| Bridging Rows | 2 | |
| Finish | white | |
| Run Length | bayCount * span + cleatWidth | mm |
| Height | cleatGap + depth | mm |
| Line Intervals | Math.ceil(rafterLength / maximumSpacing) | |
| Line Spacing | rafterLength / lineIntervals | mm |
| Cleat Gap | depth <= 250 ? 10 : 20 | mm |