I am thinking about using metal siding on my walls as well. I have 2x4 studs 24 inch spacing. Since I think metal is 3 feet wide, will I have to put nailers on top of studs? If it is better I will but I just priced 1x4 and it is 6 bucks for a 10 foot long board. But again if it is better I will. Of course the metal will run vertically, so I am not sure how that will work.