My parents are in the process of adding a sun room to the back of their house. Big N was helping Grandpa last Wednesday. In fact, I think he was such a big help that he really got Grandpa's project going.
Before my son helped
After both kids helped
Big N was busy measuring and hammering for Grandpa. It sounds like both kids help to get a lot of work done on the addition in the two days they were out.
It's not like I would exaggerate the abilities of a 2 and 4 year old.