TATA Shaktee GC Sheet
Over the years, TATA Steel has altered the landscape of the roofing industry in India. The company has been a pioneer in the field of manufacturing superior quality TATA Shaktee Galvanised Corrugated (GC) sheets.
Manufactured with world-class technological expertise, these GC sheets are stronger and longer lasting than any other ordinary GC sheets. TATA Shaktee GC Sheets are not only made of virgin steel processed at TATA Steel's state-of-the-art Cold Rolling Mill but also have uniform Zinc coating on them, which gives them the required strength in fighting the weather and to last longest.
Depth and Pitch of the GC
|Class||Depth of the GC||Pitch of the GC|
|A||17.7 mm||75 mm|
|B||12.5 mm||75 mm|
|Thickness (mm)||Length||Width (mm)|
|0.30||1830 mm (6 ft)||910|
|0.35||2140 mm (7 ft)||1220|
|0.40||2440 mm (8 ft)||-|
|0.45||2745 mm (9 ft)||-|
|0.50||3050 mm (10 ft)||-|
|0.55||3660 mm (12 ft)>||-|
|0.60||4270 mm (14 ft)||-|
|0.63||4880 mm (16 ft)||-|
|TYPE OF COATING||Galvanised (Zinc) Spangled|
|COATING WEIGHT||120 gsm (gram per square metre), Class 8 (as per BIS)
(For tailor made products Zinc coating, may vary between 60-600 gsm)
|Length||+ 15 mm, - 0||+ 15 mm, - 0|
|Width - Before corrugation||+ 10 mm, - 0 mm||+ 10 mm, - 0 mm|
|Width - After corrugation||± 25 mm||±15 mm|
|Thickness||± .05 mm||± .03 mm|
|Diagonal Difference||Should not differ more than 20 mm||Should not differ more than 20 mm|
|Depth of Corrugation||± 2.5 mm||± 2.5 mm|
|Pitch of Corrugation||± 5 mm||± 5 mm|
End Lap of sheet
|Roof Slope||For Roof Cladding||For Wall Cladding|
|1 in 3 (18º)||150 mm||100 mm|
|1 in 4 (14º)||200 mm||100 mm|
Side Lap of sheet
|For Roof Cladding||1½ Corrugations|
|For Wall Cladding||1 Corrugation|
|End Overhang (X)||300 Mm|
|Side Overhang (Y)||100 Mm|
Usage of recommended accessories leads to enhanced life of Roofs and Walls. Poor and substandard quality of accessories may adversely affect the superior quality of cladding sheets leading to reduced life. Accessories and the cladding material should have similar life expectancies as that of the main structure and hence criteria for selecting the accessories such as Fasteners, Gutters and Flashings must be based on the design life of the structure.
Researches executed on causes of steel building failures worldwide indicate that almost 80% of failures start from the fasteners. Since fasteners, used on cladding and structure together, constitute roughly 6-8% of the entire project cost, several builders have the tendency to neglect this vital aspect of their project.
Fasteners used on steel Roof and Wall Cladding must be of good quality and properly galvanized conforming to IS:730 standards. This will go a long way in providing a weather proof and long lasting roof. Different components of good quality fastener are depicted below in Figure-8.
There are various kinds of hooks and screws available in the market depending upon the material and type of purlins on which sheets need to be fixed (Figure-9). G.I. Hook Bolt should be used for fixing sheets to angle Iron purlins. G.I. Crank Bolt should be used for fixing sheets to channels or rectangular/square tubes purlins. G.I. Coach screw (square head) should be used for fixing sheets to wooden purlins only.
Typical Fasteners for Cladding
Types of Hooks/Screws
The rubber washer should be 25 mm in diameter and 3 mm thick with 6 mm bore to suit 8 mm diameter bolts. This bond between rubber washer and bolt ensures water proof sealing.
The G.I. flat washer is 25 mm in diameter (if it is a round washer) and 1.60 mm thick with central hole to suit 8 mm diameter fixing bolt or screw.
The sheets are fastened to purlins (in case of Roof Cladding) or side girts (in case of Wall Cladding) by minimum 8 mm diameter hook bolts at a maximum pitch of 375 mm.
Life comparison of fasteners used with rubber and bitumen washers
Usage of recommended fasteners enhances sheet life.
Usage of poor quality fasteners lead to rusting that begins at the joints and spreads to the sheet reducing sheet life.