An accurate study of the roof should be done and several important matters must be considered:
The supporting structure (frame) must hold the weight of the tile (it could be heavier for the new roof tiles.) Overloading due to snow should be considered in weight parameters.
Depending on the tile you choose, a minimum slope pitch should be considered.
The location also should de considered fallowing the rules and recommendations for local weather conditions.
The type of insulation should be adapted as per nowadays requirements. Roof ventilation is mandatory according to the latest regulations.
The length of the roof slope should not exceed the horizontal imposed by the installation rules for the new product to be installed. We recommend you to contact a specialized company in roof coverings. As manufacturer, we can suggest you a few options according to your needs.