Cement Fibre Roofing Sheet

Introduction

Cement fibre roofing sheets are manufactured employing completely indigenous technology, plant and machinery. The physical characteristics of cement fibre roofing sheets such as thermal insulation, fire resistance, water absorption and water permeability are favourable compared with AC & CGI sheets. Apart from utilisation of agricultural wastes, the manufacture of these sheets in large quantities will reduce the consumption of timber in the construction of houses. These sheets can be used for temporary and semi-permanent structures. Coir waste, wood wool or Sisal fibre can be profitably utilised in combination with cement as a binder for production of corrugated or plain roofing sheets. Shearing waste (baby fibre) and coconut pith also account for a large amount of agro industrial waste. Unlike other cellulosic materials, fibre is free from water soluble polyphenols and makes a strong board with ordinary portland cement as binder. This property of the fibre and pith has been utilised in making corrugated roofing sheets. Wood wool used largely as packing material is obtained from soft wood such as 'fir', 'chir', 'kail', 'deodar' which yields good quality fibre of suitable length and width. Sisal fibre is an other suitable fibre available from Sisal plant and is being extensively used in other developing countries like Africa for making board and roofing sheets. For making corrugated sheets, weighed quantity of the fibre is soaked in water for sometime which is mixed with pressed quantity of cement thoroughly. The cement coated mixed stuff is uniformly spread on the drag mould and is pressed by hydraulic press. The wedged mould assembly is then rolled out of the press and is cured for 3-4 hours in the curing yard. Water proofing paint is applied on top side of the sheets after demoulding.

List if Machinery/ Equipment: Moulds
Hydraulic Press (20 T.Cap.)
Roller Tracks
Shipping Device
Gantry Cranes
Power Trimming Device

Uses : Used in Construction for roofing

Advantages:

• Coir fibre/wood wool corrugated sheets require 30 percent less cement as compared to asbestos cement sheet.
  
• The sheets are light and can be carried over hilly and rough roads without any breakage.
  
• The sheets are strong and possess good bending strength. A man can safely walk over them.
  
• The sheets possess good thermal insulation and are expected to provide greater comfort in tropics as compared to AC/CGI sheets.
  
• Their preparation needs neither heavy machinery nor high capital investment. The sheets are 50 percent cheaper than AC/CGI sheets.
  
• These can be laid on roof like AC/CGI sheets.
  
• The roofs made do not require any further finishing or waterproofing treatment.
  
• These are fire-resistant.

Economic Data

Fiscal Incentives : 100 per cent excise duty exemption on finished goods.
Fixed capital - Rs. 34,60,000
Working capital - Rs. 7,18,000
Break even point - 53.70%

Production Capacity: 30,000 sheets/annum of size 2mx1mx7mm.

Inputs Required:
Raw Materials: Cement, coir waste/sisal fibre/wood wool, additive

Transfer Forms: Negotiable

Main Application: Construction/Mining/Transport

Source: Technology Bureau for Small Enterprises
APCTT Building, Qutub Institutional Area
P.O. Box – 4575
New Delhi – 110016, India