G.F. Sprague is Sharon, Ma's replacement window contractor. Whether you have aluminum windows, or vinyl windows, we have the replacement window option for you. All of our work is backed up with a 40 year handiwork warranty. So you have self-confidence with GF Sprague with all your work for replacement windows. G.F. Sprague has been in company since 1969 and has more than 10,000 satisfied consumers.