 Paxton's roofing system incorporated his elegant solution to the problem of draining the building's vast roof area.Like the Chatsworth Lily House (but unlike its later incarnation at Sydenham) most of the roof of the original Hyde Park structure had a horizontal profile, so heavy rain posed a potentially serious safety hazard.Because normal cast glass is brittle and has low tensile strength, there was a risk that the weight of any excess water build-up on the roof might have caused panes to shatter, showering shards of glass onto the patrons, ruining the valuable exhibits beneath, and weakening the structure.