I want to board my loft up to use as a hobby room. What is the minimum thickness chipboard i should use?
Typical flooring would be the equivalent of 3/4″ tongue and groove plywood as a minimum. You might get by with 5/8″ but I wouldn’t do that. You say you have thick beams but there is more information needed to determine the best subfloor to put. My wife’s attic room had 1/2″ OSB I added another 1/2″ of plywood on top then a laminate floor for the final finish. Here is a site that might be helpful: http://www.toolbase.