I have only experience from KH and Bethelbuilds so cannot say if it was different in Assembly hall buildings, guess not. I am absolutelly not skilled in construction thing, but I had been following one nice brother earlier in hallbuilds helping with one specific area of construction. So I had experience in that and was always accepted as part of the group doing that part of construction as I could do the simpler jobs for them and they could concentrate on more important things.
There wasn't sufficient amount of work for whole time so I had lots of idle time in hall builds, there were small ad-hoc things that I was then invited from coffeetable. But I must say that in general people were in good mood in hall builds, not least for food and coffee service. Then the rules changed that you had to be in good standing and approved by local elders, that was end of it to me. On the other hand my lifesituation wouldn't let me do lots of building anyway.
But it was very different in Bethel build, most of the people there were real professionals in their area, and to be honest, not very humble in many cases. I was temporary unskilled helper there and boy those pro's could curse and look badly if you missed something they knew by heart. It was much easier to do lonely things like giving directions to cranes. What I really couldn't understand was the amount of time that was lost for changing gears for food and back. There was arrangement made for lazy types that they were served food outside the premises and they did not have to change. I needed some rest so I did the whole showering/clothing thing couple extra times each day, most of us did. I admit that I also wanted to feel the atmosphere in dining room during those weeks I worked there.
CP