In southern parts of the country where they don't need to deal with snow loads, it's acceptable to use 3/8-- roof sheathing, which means it's also acceptable to use 1-- roofing nails on asphalt shingles. A 1-- nail will fully penetrate through 3/8-- roof sheathing, but it won't fully penetrate 1/2-- sheathing.Jul 17, 2012read more >>