Guides
Purlin and girt spacing
For LYSAGHT TRIMDEK 1015 roofing sheet at 0.47 mm total coated thickness, Tata BlueScope Steel's own installation guide allows a roof purlin up to 1600 mm apart on an internal span and a wall girt up to 1900 mm apart, tested to Wind Zone 3 under IS 875.3. A different sheet, a different thickness or a different wind zone moves every one of those numbers, so the spacing that actually governs your shed comes out of a structural design done for that roof, not off a chart on a website.
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Jay Shree Infra sells colour-coated roofing sheet and GC sheet across the counter in Saharsa and out into Supaul and Madhepura, in Tata Durashine, Jindal and Kamdhenu. Every one of those sheets sits on a purlin across the roof and a girt up the wall, and how far apart those supports can stand is answered below with the figures makers actually publish, not a guess. Not every size is in every brand on a given day.
Every published spacing figure carries three riders nobody drops: the sheet's own thickness, the wind zone the shed sits in, and whether the purlin in question sits at the open end of a run or is held on both sides by its neighbours. Tata BlueScope's own LYSAGHT TRIMDEK guide prints six different numbers for one sheet profile because of exactly that, and its own footnote asks a buyer to check with its Building Products office before adopting any of them for a design. The table below is what these sources actually publish, not one figure smoothed into an average.
The numbers
LYSAGHT's own numbers for a purlin and a girt
Maximum centre to centre spacing for a roof purlin and a wall girt, by sheet thickness and span position, as each source publishes it.
Scroll the table sideways to see every column
| Published by | Purlin or girt | Span position | Sheet thicknessmm | Maximum spacingmm, centre to centre |
|---|---|---|---|---|
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | Single span | 0.47 | 1090 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | Single span | 0.50 | 1300 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | End span | 0.47 | 1280 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | End span | 0.50 | 1400 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | Internal span | 0.47 | 1600 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Roof purlin | Internal span | 0.50 | 1800 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | Single span | 0.47 | 1780 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | Single span | 0.50 | 1900 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | End span | 0.47 | 1600 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | End span | 0.50 | 1800 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | Internal span | 0.47 | 1900 |
| LYSAGHT TRIMDEK 1015, Tata BlueScope Steel | Wall girt | Internal span | 0.50 | 2300 |
| Everest Hi-Tech corrugated sheet (fibre cement) | Roof purlin | not named | 6 | 1400 |
LYSAGHT TRIMDEK 1015 is one sheet profile from Tata BlueScope Steel, tested at two total coated thicknesses, 0.47 mm and 0.50 mm. A single span carries no neighbour, an end span has one, and an internal span is held on both sides, which is why the same sheet gets three different numbers. The wind pressure behind all six figures is Zone 3 under IS 875.3, for a building up to 10 metres high, and the source itself says spacings may vary for a particular project. Everest's Hi-Tech figure is for a 6 mm fibre cement sheet, a different material measured on a different thickness scale entirely, and is not the number a steel sheet on this rack should be ordered against.
Read the span position before the number. An internal span, held on both sides, takes a purlin about 500 mm further out than a single span on the same sheet at the same thickness, and that gap is the single biggest swing in the whole table, decided entirely by where the support sits and not by the sheet.
Thickness moves the number too, by around 200 mm at internal span between 0.47 mm and 0.50 mm total coated thickness. Our own colour-coated stock runs 0.35, 0.45 and 0.47 mm, so 0.47 mm lands exactly on the thinner published column and 0.45 mm sits close to but not on the thicker one, which is the reason confirming the exact thickness on the sheet you are buying matters more than reading a chart.
The two members
Purlin holds the roof, girt holds the wall
A purlin runs across the rafters and takes the roof sheet's screws. A girt does the same job standing on a wall, running between the columns and taking the wall sheet. Both are cold-formed steel, usually a C or a Z profile, and the only real difference between them is which face of the shed they end up fixed to.
The purlins and girts kept here are cut to a shed's own drawing, sizes and thickness settled against that span, not sold off a fixed size list. Where a job wants the exact profile a spacing chart is tested on, LYSAGHT is the published reference behind the figures above; where it does not, a cold-formed C or Z section to the required depth and thickness does the same job.
The limit
The structural design decides, not a chart
Tata BlueScope's own article on choosing a purlin says the design turns on the bay spacing, the strength and deflection that follow from it, and that cold formed design codes must be used to get there. No published table, from any maker, stands in for that calculation. What a table can honestly do is show what a maker has tested and published for one sheet, at one thickness, in one wind zone, which is exactly what the numbers above are, and exactly why LYSAGHT's own guide asks a buyer to check with its Building Products office before adopting them for a design.
A shed built without a formal drawing is still built to a span, whatever decided it, and that span is the number a phone call actually needs. Bring the drawing if there is one; bring the span, the sheet thickness and the roof pitch if there is not.
At this counter
Cut to the drawing, loaded with the sheet
Jay Shree Infra keeps colour-coated roofing sheet in Tata Durashine, Jindal and Kamdhenu, at 0.35, 0.45 and 0.47 mm, alongside GC sheet, and purlins and girts cut to a shed's own span go out on the same load. Tell us the span, the sheet thickness and which wind zone the site sits in, and we cut and punch to that. Choosing between a colour-coated sheet and a plain GC sheet first: that comparison is the page for it.
Everest is on the rack too, for the fibre cement roofing a shed sometimes wants over steel. Its own published purlin spacing sits in the table above for exactly that reason: a different material, a different chart, and a different call before you order it. See the full range at Shed, Godown & Roofing.
Sources
Two makers' own charts, and the article behind them
The published spacing table, the article explaining what actually sets a purlin's design, and one more maker's own figure for a different roofing material.
- LYSAGHT TRIMDEK 1015 Design and Installation Guide, with the Maximum Support Spacings table and its wind pressure basisTata BlueScope Steel / Tata Steel Colors
- Choosing the correct Purlin for Roof framing, on span, strength, deflection and cold formed design codesTata Steel Colors
- Hi-Tech corrugated roofing sheet, with its own maximum purlin spacing figureEverest Industries
Questions
Purlin aur girt spacing ke sawal
Purlin kitni duri par lagti hai?
It depends on the sheet's thickness, the span position and the wind zone the shed sits in. Tata BlueScope's own LYSAGHT chart runs from 1090 mm on a single span at 0.47 mm total coated thickness up to 1800 mm on an internal span at 0.50 mm. A different sheet or a different wind zone moves every one of those numbers, so the shed's own structural design decides it, not a chart on a website.
Girt aur purlin me kya fark hai?
A purlin runs across the roof and carries the roof sheet. A girt runs up the wall and carries the wall sheet. Both are the same kind of cold-formed steel section, usually C or Z shaped, fixed on a different face of the same shed.
0.47 mm chadra par purlin kitni door rakhein?
LYSAGHT TRIMDEK 1015 at 0.47 mm total coated thickness publishes 1090 mm on a single span, 1280 mm on an end span and 1600 mm on an internal span, tested to Wind Zone 3. That is one sheet profile's own tested figure, not a rule for every 0.47 mm sheet on the market, so confirm the figure for the exact sheet on your order.
Kya purlin spacing sab jagah ek jaisi hoti hai?
No. The same LYSAGHT sheet gets a wider spacing under a lighter wind zone or a lighter roof load, and a tighter spacing where the wind pressure is higher. That is why a published chart always names its own wind zone and building height, and why the number for your shed is a design question, not a look up.
Girt ki spacing purlin se zyada kyun hai?
Because a wall carries only wind pressure, while a roof carries wind pressure and foot traffic together during maintenance. LYSAGHT's own table reflects that split directly: at 0.47 mm, wall girts run to 1900 mm on an internal span against 1600 mm for a roof purlin at the same thickness and span position.
Before you order
What to confirm before a purlin and girt order
Each one moves the spacing number in the table above by itself.
Purlin ya girt kis span par lag rahi hai, single, end ya internal?
That one word changes the maximum spacing by several hundred millimetres on the same sheet at the same thickness.
Sheet ka total coated thickness kya hai?
0.47 mm and 0.50 mm sit on two different rows of every published chart; the sheet in your hand decides which row applies.
Site ka wind zone aur building height kya hai?
Every published spacing figure is tested against a stated wind zone and height. A different site changes the number even when the sheet does not.
Kya koi drawing hai, ya sirf span aur pitch batana hai?
A drawing settles the cutting and punching outright. Without one, the span, the sheet thickness and the roof pitch do the same job over the phone.
Colour-coated sheet chahiye ya GC sheet?
The sheet decides which thickness options are even on the table, and thickness is one of the three numbers that sets the spacing.
Contact
The span, and the sheet going on it
No published chart replaces a structural design done for your shed. Tell us the sheet, the thickness and the span on +91 6202 967 218, and the purlin and girt go out cut and punched to that.
Shop hours: All 7 days, 9:30 AM to 6:00 PM