Looking at the Plywood Grade and Span Ratings Stamps is confusing. I beg your pardon could you clear this up?
You’re building an economical home
Use 6 ply 3/4″ AC T & G plywood
Using 3/4″ T & G Norboard it has no holding power for nails for both hardwood floors and underlayment used under linoleum.
Use a bare minimum of 4 ply 1/2″ CDX plywood
Using 1/2 Norboard the way that it is formulated it will not allow moisture to leave the stud cavity. When the winter comes the moisture then freezes to the sheathing and in the spring it starts the mold process.
Use a bare minimum of 4 ply 1/2 CDX plywood for standard shingles.
Use 5 ply 5/8 CDX plywood for laminate shingles and/or cedar. shakes
Again using 1/2 Norboard it has no holding power for roofing nails.
You’re building high-end home use the following:
For flooring; Use 2 layers of 6 ply 3/4″ AC T & G plywood
For Wall sheathing; 5 ply 5/8 CDX plywood
For roof sheathing; 5 ply 5/8 CDX plywood for wood, laminate shingles,or steel roofing
6 ply 3/4 CDX plywood for a slate roof