Continuous purlin over many bays
Lapped Z purlins act as one continuous member over the rafters, carrying the roof sheeting from end to end of the building.
Purlins & Sag Rods
Z Purlin
Z Purlin is a lipped Z section for roofs and walls of steel buildings. Because one Z nests into the next, purlins can be lapped or sleeved over each rafter and run continuous across several bays. Specify depth, flange, thickness, steel grade, finish and the quantity you need.
At a glance
Z Purlin at a glance.
The flanges let one Z sit inside the next
The two flanges point in opposite directions, so the end of one purlin slides inside the next over a rafter and the lap is bolted through.
4 to 14 in deep, 10G to 16G
4–14 in (100–350 mm) deep, 2.75–3 in (60–90 mm) flanges, 3/4 in (20 mm) lips, 10G–16G (1.3–3.15 mm), in ASTM A653, S350GD / S450GD or G450 grades, plain, galvanized (G90 / Z275 / Z350) or red oxide primed.
Lap over the rafter and bolt through
Each purlin is bolted to a cleat on the rafter. At an internal rafter the next purlin is nested over the end of the last for the lap length the design sets, and the two are bolted together through their webs. The sheeting is fixed to the top flanges and sag rods keep the lines straight.
Common applications
Where it is used.
Multi-bay roofs
Long warehouses and factories run lapped Z purlins over many rafters. The laps make the line continuous over the internal supports.
Wall girts
Z sections are also used as girts on long walls. Lapped over the columns, they carry the cladding in one line.
Agricultural buildings
Farm sheds and stores use Z purlins for their long, repeated bays. Galvanized sections suit open-sided buildings.
Questions answered
Common questions.
What else is a Z purlin called?
In the United States it is also called a Z section.
Why are Z purlins lapped over the rafters?
A Z section nests inside the next one, so two purlins can overlap over a rafter and be bolted through their webs. The lapped line acts as one continuous member over the internal rafters. GV supplies Z purlins 4 to 14 in (100 to 350 mm) deep in 10G to 16G (1.3 to 3.15 mm) steel.
Part of the roof and wall systems
Z Purlin forms the continuous lapped runs, with C Purlin at eaves and openings and Sag Rods keeping the lines straight.
Explore cold-formed systems ↗Z Purlin specifications
Z Purlin configuration
ParameterUS / PrimaryMetric / Additional
Height (H)4-14 in100-350 mm
Flange (B)2.75-3 in60-90 mm
Lip (C)3/4 in20 mm
Thickness (T)10G-16G1.3-3.15 mm
SteelASTM A653, S350GD / S450GD, G450ASTM A653, S350GD / S450GD, G450
FinishPlain, galvanized (G90 / Z275 / Z350), red oxide primerPlain, galvanized (G90 / Z275 / Z350), red oxide primer
Cold-Formed Profiles & Sections
Related components
Purlins & Sag Rods
C Purlin
Height (H): 3-14 in / 75-300 mm · Flange (B): 2.35-3 in / 60-75 mm
Specifications
Purlins & Sag Rods
Sag Rods
Diameter: 1/2, 5/8 in / 12, 16 mm · Length: 3-10 ft / 900 mm-3 m
Specifications
Strut Channels & Accessories
Universal Strut Channel / ‘C’ Strut Channel
Thickness: 12G 13G 14G 16G / 2.5 mm 2.3 mm 2.0 mm 1.5 mm · Size: 13/16" x 1-5/8" 1-5/8" x 1-5/8" 2-7/16" x 1-5/8" 3-1/4" x 1-5/8" / 21 mm x 41 mm 41 mm x 41 mm 61 mm x 41 mm 81 mm x 41 mm
Specifications