Abstract: A method of reinforcing or retrofitting building roof structures against hurricane-force winds which does not require removal of part or all of the roof. The improved method includes directing a thin stream of a liquid polymer foam adhesive under pressure upwardly along the intersections of the rafters or support members and the roof panels, preferably on both sides of the support members. The foam adhesive then creams and foams, forming polymer foam adhesive gussets which firmly adhere to the adjacent surfaces of the support members and roof panels. This method increases the pull-off strength of a roof about seven fold and is able to withstand hurricane-force winds.