Development of Alternative Roofing System by Using Ferrocement Channels

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The cost of construction is rising day by day due to increasing cost of basic building materials such as steel, sand, cement, brick, timber and labour. The cost of construction using conventional building materials and construction techniques in not economical particularly for low income groups of population as well as middle income groups. Therefore there is a need to develop a cost effective construction technique either by up-gradation of conventional technique or by applying new technique. This paper includes the construction process and compares construction cost of ferrocement roofing channel system with conventional roofing system. This roofing system is designed as a segmental element, which is very easy to cast, cure and then manually erect over the bearing walls. The strength and rigidity are developed through the shape of this roofing system and it is cost effective. Hence it is ideally suited for prefabricated construction particularly for low cost housing.

Introduction

Ferrocement is a form of reinforced concrete that differs from conventional reinforced concrete primarily by the manner in which the reinforcing elements are dispersed and arranged. It consists of closely spaced, multiple layers of mesh or fine rods completely embedded in cement mortar. A composite material is formed that behaves differently from conventional reinforced concrete in strength, deformation, and potential applications, and thus is classified as a separate and distinct material. Unlike conventional concrete, ferrocement reinforcement can be assembled into its final desired shape and the mortar can be plastered directly in place without the use of a formwork.

Welded mesh, mild steel angles or bars are used for forming skeleton, while chicken mesh, square mesh or expanded metal are used as mesh reinforcement. Mortar mix may be 1:1.5 to 1:3 by volume. With ferrocement it is possible to fabricate a variety of structural elements, may be used in foundations, walls, floors, roofs, shells etc. they are thin walled, light weight, durable and have high degree of impermeability. Applications of ferrocement is in all fields of civil construction, including water and soil retaining structures, building components, space structures of large size, bridge components, water tanks, domes, dams, boats, conduits etc.