Complex sentence: Waterhouse avoided using a Polychrome scheme as seen in High Victorian Gothic buildings such as St Pancras railway station believing it to be impractical as Manchester's industrial atmosphere would quickly ruin the effect and decided a uniform stone exterior was the better solution.
Split into simpler sentences: Waterhouse avoided using a polychromy scheme for the exterior, as seen in High Victorian Gothic buildings such as St Pancras railway station. He believed it to be impractical as the industrial atmosphere in Manchester would quickly ruin the effect and decided a uniform stone exterior was the better solution.