Visaka Industries - Fixing Procedure for Asbestos Cement Sheets

	ESTIMATING ROOFING ACCESSORIES
	The covering capacity of the following Roofing Accessories corresponds to the width of the sheets : - All Ridges (number in pairs) - North light curves (in numbers) - Apron pieces (in numbers) - Eaves Filler pieces (in numbers).

	FIXING PROCEDURE :
	Fixing procedure should be followed as per IS 3007/1964 : Code of practice for laying of Asbestos Cement Sheets - Part 1, corrugated sheet:
	1. Before laying of sheets check the purlin spacing and the length of the sheets to ensure that the arrangement of sheets will provide the required end lap (Min. 150 mm as shown in fig 5.) and the specified overhang at eaves (Max. 300 mm and at the ridge (Normally 75 mm).
	2. The sheets to be laid with the smooth side facing the weather.

	3. For left to right fixing, start at eaves with sheet 'A' - (Fig. 1) to the purlin with downward corrugation on left and upward corrugation on right, so that the downward corrugation of the next sheet can site on it.
	4. Next place the sheet 'B' which is mitred at the bottom right hand corner in the manner shown in fig 2.
	5. All other sheets in this slope including ridge sheet 'C' should be fixed similarly.
	6. Start the next tier with sheet 'D' which is mitred at the top left hand cornet. Make sure that the side lap (1/2 corrugation Min.) is correct. Mitring is done as shown in Fig. 3
	7. Continue with sheet 'E' which is mitred at the top left hand corner and bottom right hand corner.
	8. At ridge fix the sheet 'F' which is mitred at the bottom right hand corner.
	9. Fix 'G' & 'H', which are mitred on the top left hand corner.
	10. Fix 'I' without mitring. (whenever four sheets meet at a lap joint the intermediate two sheets are to be mitred).
	11. The bolt should pass through the second and last corrugations, i.e. bolt distance between two successive sheets should be 279.4 mm (Fig 4.)
	12. For 8mm dia Hook blots (conforming to IS 730-1978) - 10 mm dia hole should be drilled (never punched), on the crown of the corrugation.
	13. Bitumen washer, G. I. Washer to be used while fixing the sheet with Hook blots.
	14. Hook bolts should not be tightened too tightly.
	15. Sheets should be fixed with Hook bolts at intermediate purlins also.
	16. Mitring or cutting of sheets should be done with an Ordinary Carpenters saw only.
	17. Always use a cat ladder during installation for safety and better results.

	> FIXING OF VISAKA AS-10 SERRATED ADJUSTABLE RIDGES
	1. Commence from Right hand verge - lay a few inner Rolls R1 : The rolls should sit flush with the whole sheets in a straight line (Fig. 6).
	2. Commence laying R2 (outer rolls) - on the opposite slope and in the same direction of R1, so that the small serrations rest with the side lap of the sheets, ensuring a snug sitting of R2 over the roofing sheets and also staggered jointing between R1 and R2.
	3. The ridge is secured with the same bolt which is used on the roofing sheets at the right purlin.


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