IT'S TIME TO FIRE PROOF YOUR HOUSE:
USE ONLY INCOMBUSTIBLE MATERIALS
IT'S TIME TO LEAVE THE "WOOD AGE" OR ANY OTHER COMBUSTIBLE BUILDING MATERIAL (PERIOD)
The exterior of a home should not only be incombustible but also offer protection to the occupants for a minimum of 4 hours, when a fire is burning outside. Basically it shouldn't let the temperature rise in the interior to a level that you should determine [not the rating people], regardless what fire is burning outside; even if it is a gasoline tanker that just crashed against the house. That number must be customized to the occupants needs, as for some this number will be lower than others, depending how you support heat. This are the requirements you should have when designing your home. Short of a volcano, a meteor, or other higher force event, your home will be there to protect you and your family.
To resist a wild fire (brush fire) is not only easy, but it should be the minimum code for building a house; it is ridiculous how most of you supposedly intelligent people let even a SMALL fire steal what you worked for all your life.
Most so called fire ratings are a starting point, but trust and verify those ratings; tests should be made to the chosen materials. Remember that wood doors are fire rated. If it burns slow, it's OK! (THE JOKE IS ON YOU).
In all cases, an air chamber, 1 to 2 inches of air space between exterior and interior wall, must be used to stop the heat from rising in the interior to unacceptable levels. Air circulating between walls has to be forced and go through a cooling system that could be a thermal mass and have a backup battery for power outages or generator outage.
On the interior of the house all walls should be incombustible. Drywall is not incombustible and even if it could be used inside the house, in the garage it shouldn't be used at all. The garage ceiling needs metal or other 4 hour rated material suspended from the ceiling to allow an air chamber to protect the floor above. Possibly a sprinkler system and even a forced air chamber must be used and tests must be made to the system and materials used to make sure they perform as desired (a 4 hour rating is heavy fire directly on it for 4 hours), a situation that no car fire should be able to provide for such long period.
If a car was to catch fire in our garages nothing besides smoked walls will occur; one could even be home and not even notice it, if not for the alarms, as the doors from the garage to the house are air tight.
We always provide protection for at least 2x the worst case scenario.
In a really hot fire even cement based products or steel will suffer local damage. (YES WE KNOW THAT ALL MATERIALS WILL MELT AT SOME POINT SO PLEASE DON'T BOTHER, WE ARE TALKING ABOUT BRUSH FIRES, HOUSE FIRES, AND GASOLINE FIRES) but in most cases those will be mostly cosmetic damage and should never render the house inhabitable, but because some smoke penetration should always be expected regardless of how well the house is sealed, all houses should carry an air breathing system and a safe room/basement to achieve the best protection.
Remember YOU SHOULD NEVER have to leave your house because of a fire or weather related event.