Abstract: This invention generally relates to an integrated photovoltaic roof assembly for constructing a building integrated photovoltaic system commonly known as BIPV. The invention enables the photovoltaic panels to serve as a water proof envelop of a building while generating electricity from the sun. The photovoltaic roof assembly consists of a plurality of solar panels fitted to a lattice mounting structure comprises of perpendicularly interconnected profiles with flushed surfaces and built-in gutters. There are few components required and no restriction on the gradient of the roof. Neither skilled labor nor special tool such as welding is required for installing the integrated photovoltaic roof assembly.