None of my people can get master building . They've been buldind for three days and always status bar stops increasing at certain limit. I've tried with many different people. They just die before getting Master

Yeah builders are so frustrating. You have to keep on them all the time and constantly pull them back to stay on the job. I think that the bar will not increase if it says that they are "examining" a hut - they have to "fix" it. It can be done though, keep on keeping on!
Good luck

There are other ways to improve building skills. Check out this post, but beware, it is a spoiler!.