Shell roof is basically the modification of a pitched roof and covers large areas of the building. Moreover, shell roof is three-dimensional structures consisting of thin membrane slabs, curved in one or more directions which transfer the loads on points of support, i.e. columns, beams, walls etc. Shell roofs are built with several materials such as in situ reinforced concrete, timber, steel sheets, ceramics, glass, plastics, hard board, lattice and composite structure etc.
In shell roof construction, the slope of the roof and the curve of the arc must be carefully designed so that the building remains stable. Shell roof is not suitable where the roof is required to be at different levels, as the entire structure of the roof must be built at a single level. In shell roof construction, lighting and ventilation arrangement are also difficult to install.