dont use the fire retardant issue on roof ...... sales gimmick ... by the time the fire goes up the roof .. there's go the whole house ...

the heat maybe unbearable to ppl on attic ... but the heat will not cause fire ... thermodynamics is always in motion ... the heat is dispersed by the atmosphere



i do not recommend Rockwool .... it's also used for hydroponics ... this maybe a joke ... but if your roof leaks .. and the water seeps in the rockwool ... some plant might grow on it .... since that's where organic vegies came from

use the Cellulose ... besides not growing plants ... it has the best fire retardant functionality (if you like fire retardant)


remember to have air duct + aluminium roof ventilation to help disperse the heat in rooms ... without air ducts ... the air take the easiest path from the small gaps in the roof ... and wont take up the heat from the rooms ... basically reducing it benefits from 100% to mere 10% (unless for fully sealed roof .. but there's no such roof except factories)