A lot of homeowners look at the cost of a residential roof replacement estimate and think “how long is this going to take?” and chalk the entire cost up to labor. They deduct the amount of materials they found at their local hardware store (which isn’t the same materials your roofing contractor will be using anyway) and they assume what’s left is just labor. This misunderstanding is why people opt to do a DIY roof replacement or work with a neighbor if they’ve offered.
Labor is still a vital part of the cost but it isn’t the entire thing. Labor covers the employees or subcontractors your roofing company employees, and this factors in not only the total number of hours but experience, benefits provided to employees, and more. Just like your salary is determined by many factors, so are the salaries of the roofing contractors, which is then divided up amongst many jobs.
A residential roof replacement cost helps cover the labor, the employee benefits, and compensates them for their experience, the risk of the job, and more. This is also why labor costs may vary from job to job, depending on the difficulty, the risk, and more. Remember that a crew will come out and spend an entire day extracting your old roof and adding a new one, which isn’t easy, and you’d much prefer to pay an experienced team than cut corners and risk an improper job with more issues down the line.