GNP Construction is Southampton, NY 11968 leading roofing and siding contractor. We are a family-owned and operated business for 30+ years that cares about providing quality service. As Southampton, NY’s leading Roofing and Siding Contractor your Satisfaction is our Guarantee. We use top-of-the-line products from leading manufacturers: Alside, Owens Corning, Andersen Windows, and Slocomb. We have completed thousands of roofing, siding, and window contractor services here on Long Island and many have been in the town of Southampton, NY.