Most shingle roofs can be completed in a single day, however there are many factors involved such as size of the roof, number of hips, valleys, penetrations, steepness, and so on. Single-ply roofs typically take more than a day if greater than 20 squares in size (2,000 sq ft) Coating systems typically take more than one day due to it being applied in multiple coatings each of which must dry prior to the next one being applied.