Rooms over Garage
Will your new house have a bedroom above the garage?
If so you should check what the builder specifies in the way of Insulation between the garage and the room floor.
Although regulations quite often specify insulation on external walls they usually don’t consider above the garage.
Why this matters
In winter garages can get very cold, particularly if the garage door is left open.
In summer the garage can get very hot. . . more so if the garage door faces west and absorbs the afternoon sun..
This means that in both summer and winter the lack of insulation can make the room uncomfortable!
What You Can Do
Make sure you discuss with the builder the option of putting insulation in the garage roof before the ceiling is installed.
Doing it then is going to be much cheaper than trying to do it later.
Already built? . . . perhaps you could add Insualtion to the garage door.