Finishing a drywall seam — tape plus three coats feathered wider

Finish a tapered seam by bedding paper tape in a first compound coat, then a fill coat and a finish coat each feathered wider and sanded flush — a 3-coat Level 4 finish (GA-216). Plan ~280 sq ft of compound per gallon per coat (USG); tape ≈ each sheet’s perimeter.

What this diagram shows

A cross-section of a tapered drywall seam being finished to a Level 4 finish. The two factory-tapered edges form a recess centered over a stud. Paper tape is bedded in a first coat of joint compound, then a fill coat and a finish coat are each applied wider and feathered out, and sanded flush. This three-coat Level 4 finish follows GA-216. Joint compound covers about 280 square feet per gallon per coat per USG, and tape runs roughly the perimeter of every sheet. A butt joint has no recess, so it crowns and must be feathered 16 to 24 inches wide.