Abstract: A mechanized roof shingle laying system has a plurality of lateral supports which are attached to a roof. Desirably, a plurality of horizontal track sections span the entire roof and engage alignment tabs on the lateral supports. A carriage, ridden by an operator, is movable along the horizontal track sections. Shingles carried by the carriage are laid on the roof along a lip guide of the horizontal track sections and produce an accurate alignment of the shingles. When a row of shingles has been laid in alignment upon the roof and fastened thereto, the horizontal track supports are moved to an adjacently spaced alignment tab of the lateral supports so that another row of shingles can be positioned on the roof. The system provides a high production rate with consistently good accurate alignment of the shingles.