The quick answer is: 40 - 50 hours per week which typically includes Saturdays.
Your question could also suggest that you are wondering if a construction job could mesh with your current responsibilities or lifestyle.
The good news is that there is a shortage of construction workers today so you could eventually approach the bargaining table with your personal wishlist of more pay and less work.
If you are young, physically able and generally have a curiosity about how things are put together, I am going to recommend that you immerse yourself in construction, pick up a framing hammer and: talk to journeyman workers, find local organizations e.g. carpenter's unions, youtube wood frame construction, google how to run a contracting business and research anything and everything that interests you about the construction industry.
The harsh reality is construction is difficult manual labor, but if you can learn to see the big picture, that you can run your own contracting business one day, or how an engineer designed an earthquake-proof house or how an architect designed a corner window could pivot your interests to engineering or architecture school.
Not only will you learn the important skill sets of building a house, but you will also learn to develop discipline, learn how to deal with others on the jobsite and hopefully learn to be a decent human being. So if you plan to pursue a career in construction, go all in with eyes and ears fully open.
In the end, whatever you decide to do, you will find that your success in a career is usually directly related to the amount of time you choose to spend on it.