George is building a fence. He builds his fence at a constant rate of 1/3 section of fence every ½ hour. At this rate, what fraction represents the section of fence George can build per hour?

To build 1 fence section in 1 hour, George needs to build 1 section per 1/2 hour. Since 1/2 of fence section = 2/2 parts of fence section = <<1/2=1/2>>1/2 fence section, building at a constant rate of 1/3 section of fence every ½ hour represents 1/2 of fence section per hour. Answer: \boxed{\frac{1}{2}}.