To expel the hot air / heat accumulated between the roof and ceiling .....

1. Ceiling exhaust fan to circulate the hot air plus

2. Wind turbine ventilator


For the ceiling exhaust fan, install a timer to operate at regular interval esp from noon onwards.

1. A steep gradient will be better for water flow. However the angle will depends on the length of extension and neighbouring units. An experienced contractor would know and advise.

2. It helps but water leak can come from anywhere especially during heavy thunderstorm. As for thief breaking in, no comment as it also depends how detetmine he is.