The answer to this question is, it depends. There are a number of factors in your roofing project including the size of your roof, type of roof materials to be used, time of year to maximize daylight and labor time, number of people in the roofing crew doing the work, and local building code requirements such as mid-roof inspections, adding decking, or additional nailing requirements for high-wind locations.
The average residential roof size in the US is about 1,700 square feet or 17 squares. All roofers use “squares” to measure and estimate roofs. A square is equal to 100 square feet of roofing surface. Most residential roofing projects of this size can be completed within 1-2 days but can easily extend by several days based on the above variables.