Can the roof be waterproof in such hot weather?

If the cement surface is complete, you can use Digou super-permeable waterproof guard to waterproof it (if it is not complete, you can use Digou Meifengbao to repair it completely).

If the gap between tiles is complete, you can use the trench stone tile waterproof guard to make it waterproof (if it is not complete, the trench butyl porcelain glue can be completely filled).