Investigating Potential of Bio-Fiber Based Roofing

With the climatic conditions changing towards hotter, effective roof insulation methods are essential to maintain comfortable built environmental temperature. Roof insulation can be over deck or under deck. Conventionally Lime terracing, Stone slabs, Thatch roof and GI sheets are being used as roofing materials in low-cost houses. Although they provide a good and long-lasting roofing system, they perform poorly in insulation properties. To improve thermal insulation properties of these roofing system, biomass-soil can be a potential low-cost alternative. Biomass is being used as over deck thermal insulation in roofing system since long. Although it uses locally available material, cheaper, easy to apply, and being exposed to the environment in over deck system, its life is very short. It needs frequent maintenance and replacement. To improve the life of this insulation material, biomass fibers introduced in lime soil matrix casted as panels for under deck insulation can be a potential alternative. Present study discusses potential of bio-fiber based low-cost roofing system. Bamboo waste in continuous and discrete fiber form, and coir fibers have been used as reinforcement. Lime-soil mix is used as a matrix. Four different compositions of lime-soil mixed with bamboo waste of 22%, 26%, 30%, 34%, 38% of mass of total dry material have been designed. For experimental investigation panels of 300 mm x 300 mm size with and without surface treatment have been casted and physical (density, sorptivity and water absorption) mechanical (breaking load and MOR), thermal (thermal conductivity) properties and cost were calculated. The results were compared with commercially available fiber board. MOR and thermal conductivity of the panels were found satisfactory when compared to commercially available board whereas water absorption was found to be more. Thus, the developed panels are suitable to be used as under deck insulation in the conventional roofing system.