During the installation of AC sheets, a proper procedure ensures accuracy and goes a long way in making the roof long lasting and strong.
1. Do not stack more than 150 sheets, one over the other. If possible, do not expose to sunlight
2. To lift, hold the sheets only in the places marked ‘L’
3. Improper storage of sheets may result in damage of the sheets. The damage will be noticed only after installation
4. Always store sheets on three even level supports. Sheets of varying length should be stacked separately.
5. Always carry the sheets lengthwise, not width wise. If sheets have to be stored for long, keep them indoors.
6. The distance between two purlins should not be more than 1.40 meters for roofing and 1.70 meters for side cladding. Clamp with a purlin at the end of each sheet
7. Do not make holes in the sheet by punching, always drill holes. The drilled hole should be 3mm bigger than the bolt. Use a Bitumen washer to seal holes
8. The hole should be drilled at least 2.95 mm away from the edge of the sheet. Initially tighten nut bolts with the hand only. After 13-14 sheets are installed, only then should all the nut bolts be tightened together
9. Tighten the nut in such a way that the bitumen – washer can seal the space between the bolt and the hole. Do not tighten the bolt too much, otherwise the sheet will crack. Use a spanner to tighten nut finally.
10. For a secure fitting, wherever four sheets have to be joined, the corners should be mitred. The cut corners should be 150 mm in length and 44 mm in breadth. Use a saw to cut corners. Do not use a cutter.
11. Put bolts only in crowns, not in valleys.
12. The bolt should pass through the second and the last sheet.
13. Use a cat ladder for working on the roof.
14. The outlet of the gutter line should not more than 15 meters away.
15. The length of the free overhang should more than 300 mm.
PROCEDURE OF MITRING:
- For the bottom row A, the first sheet should be cut ; DDG.– Cut in the upper left corner.
- For the second and middle rows B cut the bottom right corner of the first sheet.
- E–upper left-hand corners and bottom right hand corners to be cut.
- H–cut only upper left corner of the last sheet.
- For the upper row cut bottom right corners of C, F and F. Fix I without any cut.