Roofing & Shed
GC Sheet (Tina Chadra)
Plain galvanised corrugated sheet for shed, godown and verandah roofs, dealt in from 6 ft to 22 ft with other lengths cut to order.
- Roofing & Shed
- 2 sizes listed
- GI
- 3 brands stocked
- Own delivery, 34 blocks
GC sheet is the plain galvanised corrugated chadra that goes over a shed, a godown or a verandah: steel sheet coated in zinc, with the corrugations rolled into it. Jay Shree Infra deals in it at the Saharsa godown, 0.30 and 0.45 mm thick and 6, 8, 10, 12, 16, 18, 20 and 22 ft long, with other lengths cut to order. Tata Shaktee, SAIL sheet that reaches us billed as Bokaro, and Jindal are the three names this material arrives under here. Roofs across Saharsa, Supaul and Madhepura go up under it, and it leaves on our own vehicles.
Three numbers settle a chadra order and the thickness is only one of them. The length has to cross the frame, the width has to be counted after the side lap is taken out of it, and the zinc carries its own figure in grams per square metre. The same steel without the corrugations is GP, plain galvanised sheet, which sits under steel sheets. Purlins, ridge, screws and the colour sheet beside this one are on the roofing and shed page.
Widths
What Tata publishes across its GC sheet
The two Tata Shaktee width families, in the figures Tata Steel prints for them.
Scroll the table sideways to see every column
| Family | Across the sheet | Published width |
|---|---|---|
| Wide | 13 corrugations | ~910 mm width |
| Wider | 15 corrugations | ~1220 mm width |
Both rows are Tata's own figures for Tata Shaktee, and Tata calls the Wider sheet the only 4 ft wide GC sheet made in India. It also puts the Wide sheet 13 percent over the standard 800 mm sheet, which is where that third width comes from. Take none of the three as a cover width: a corrugated sheet laps into its neighbour at the side, so what lands on the purlins is less than what a tape reads across the sheet, and how much less follows the lap you fix.
Kis kaam me lagta hai
Village godowns and PACS godowns, cattle and poultry sheds, workshop and warehouse roofs, the verandah at the back of a house, and cladding down the open side of a shed. Shed fabricators take it by the load, thekedars by the roof, and a home builder walks in for eight sheets on a cattle shed.
What the sheet sits on decides more than the sheet does. Purlin spacing, screw spacing and wind loading on a project roof are the engineer's or the maker's to approve, and on tender work we say so on the call. Bring the span and the slope to the phone and we will work out which lengths cover that roof with the fewest joins.
The mark galvanised sheet is meant to carry
Galvanised steel sheets, plain and corrugated, are IS 277:2018, and that standard is serial 7 of Schedule 1 of the Steel and Steel Products (Quality Control) Order, 2024, with immediate effect. The entry carries no size and no profile carve out, so the Standard Mark under a BIS licence covers the whole of it. Tata states that its Shaktee sheet is ISI certified under BIS.
Two things travel with a certified load. The mark comes with a licence number in the CM/L form, and BIS's scheme for this standard asks for a test certificate with each consignment, carrying that same mark, the cast or control unit number and the test results, with the coating and its grade in their own columns. On sariya the same Order stops short of the sizes below 8 mm, worked out on the TMT bar page. On galvanised sheet it stops nowhere.
Pin the thickness figure down before you compare
SAIL publishes its GC sheet from 0.5 mm to 1.25 mm and its GP sheet from 0.35 mm. We deal in 0.30 and 0.45 mm, and it is not fixed whether that figure is the bare steel or the total with the zinc on it. One sheet, two ways of measuring it, and the gap between them is small enough to hide inside a quote.
So a figure below a mill's published floor is worth a question at the counter. Ask whose sheet it is and which of the two the number stands on, on both quotes, and only then put them side by side.
Zinc has its own number
Galvanised means zinc, and zinc is sold by mass: grams per square metre of sheet. SAIL publishes its galvanised coating classes at 80, 100, 120, 180, 200, 220, 275, 350, 450, 550 and 600 gsm. Two sheets of the same thickness can sit in different classes, so the thickness alone does not describe a sheet. The class is a column on the mill's test certificate, beside the cast number, and it is a fair thing to ask for on a full load.
Adding to a roof that is already standing
Count the corrugations across one old sheet and measure it before you order. An 800 mm sheet, a 910 mm sheet and a 1220 mm sheet are three different profiles, and BIS's scheme for IS 277 lets a maker supply another profile, depth and pitch of corrugation by agreement with the buyer, as long as the imposed load condition of IS 875 (Part 2) is met. Two sheets of the same width can still refuse to nest. Give us the count and the measurement and we will tell you what sits next to it.
Brands
Names this chadra comes in under
Not every length is in every brand on a given day, so put the length and the thickness beside the brand when you ring.
Each of the three needs a word. Tata's corrugated line is Tata Shaktee, and the widths in the table above are what Tata prints for it. SAIL sheet comes to us billed as Bokaro, which is one of SAIL's own plants, and SAIL's galvanised page puts its GC sheet at 0.5 to 1.25 mm. More than one steel company trades under the Jindal name, so on Jindal sheet we go by the marking and the bill and never by the word alone.
Sources
The widths and the mark behind this sheet
The two mills that publish sizes for this sheet, the order that puts it under the ISI mark, and the BIS scheme behind that mark.
- Tata Shaktee GC sheets, with the corrugation counts and widthsTata Steel
- SAIL's galvanised products page, with GC thickness and the coating classesSAIL
- The quality control order for steel, Schedule 1 as gazettedMinistry of Steel
- BIS scheme of inspection and testing for IS 277:2018, with the marking and consignment certificateBureau of Indian Standards
Questions
Tina chadra ke sawal
Tina chadra par ISI mark hona chahiye?
On galvanised sheet the Order asks for it, and it makes no exception for the corrugated kind. The licence number is written in the CM/L form and a certified consignment comes with a test certificate carrying the same mark. Ask us what came in with the load.
Ek chadra me kitni chaudai kaam ki aati hai?
Less than the width you measure, every time, because the side lap goes into the next sheet. Fix the lap first, then divide the roof by what is left of the sheet. Say the roof width on the call and we will count the sheets with you.
Zinc coating ka gsm bhi puchna padta hai?
Yes, and it is a separate figure from the thickness. SAIL publishes galvanised coating classes from 80 gsm up to 600 gsm, so two sheets of one thickness can carry very different zinc. Tell us the job, a shed roof or cladding or a cattle shed, and we will say what has come in and in which class.
List se alag lambai chahiye to order kaise dein?
Say the finished length in feet, the thickness, how many sheets and where the roof is going up. We deal in 6, 8, 10, 12, 16, 18, 20 and 22 ft, and a length outside that is cut here against whatever the brand has come in at. So the cut length is fixed on the call and before the vehicle is loaded, because a sheet cut short cannot be put back.
Contact
Call with the length, the count and the thickness
Brand, thickness, length, the profile or the width, and how many sheets: that is what goes on the slip at this end. Add the village, because a 22 ft sheet picks the vehicle before the weight does. If the roof is already standing, count the corrugations across one old sheet before you ring, because that count and the width across it are what tell us whether anything here will sit beside it, and both take ten seconds to read off a sheet you can reach.
Shop hours: All 7 days, 9:30 AM to 6:00 PM