Painting the roof white will not help during the evening after the sun goes down.
How to insulate roof from sun heat.
First the coating reflects sunlight the moment it hits your roofing surface.
If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters.
The way i see it you have 2 options that will help.
Green roofs may be more expensive than other cool roof options but they come with extra advantages.
If you haven t encountered reflective roof coatings these are coatings you apply to metal and rubber roofsto reduce heat from roof top.
A green roof which is basically a built in rooftop garden can provide a layer of insulation that will help fight solar heat gain.
1 put a rubber coating on the top of the roof rubber is an excellent insulator.
This won t actually protect your roof directly but it will help keep the heat from building up in your roof.
When the sun heats a roof it is primarily the sun s radiant energy that makes the roof hot.
Much of this heat travels by conduction through the roofing materials to the attic side of the roof.
2 add a lower ceiling with insulation material in between the existing roof and new ceiling.
Purchase a roll of radiant roof barrier from a supplier and spread it out along your wall.
While it won t limit your roof s contact with the sun radiant roof barriers can keep heat off of your roof by limiting the space where the heat can go.
This type of insulation is designed to reduce radiant heat gain.
Insulate and irrigate with a green roof.
Staple the sheeting into your joists or studs spreading it out with your hands as you apply it.