A hand tool has a plurality of similarly or identically shaped rollers aligned end-to-end along an axle such that the outer surface of each respective roller moves about an axis define by the axle. The hand tool may be a roofing roller tool that enables an impermeable vapor membrane or sheet to be applied to a vertical wall extending upwardly from an outer perimeter of a roof. The tool may be manipulated by an elongated pole handle coupled to a roller head or roller head frame.

A hand tool has a plurality of similarly or identically shaped rollers aligned end-to-end along an axle such that the outer surface of each respective roller moves about an axis define by the axle. The hand tool may be a roofing roller tool that enables an impermeable vapor membrane or sheet to be applied to a vertical wall extending upwardly from an outer perimeter of a roof. The tool may be manipulated by an elongated pole handle coupled to a roller head or roller head frame.

An amorphous structure layer is formed on a surface layer of a bonded portion of each of side brackets. A bottomed hole layer including a plurality of bottomed holes is formed on a surface layer of the amorphous structure layer. Each of the bottomed holes has a reverse-tapered shape, which has, between an opening portion and a bottom portion of each of the bottomed holes, a bulged portion having a larger inner circumference than the opening portion. An adhesive is injected into the bottomed holes. An outer circumferential surface of the bonded portion of each of the side brackets and an inner circumferential surface of an end portion of a center beam face toward each other with the adhesive interposed therebetween.

An amorphous structure layer is formed on a surface layer of a bonded portion of each of side brackets. A bottomed hole layer including a plurality of bottomed holes is formed on a surface layer of the amorphous structure layer. Each of the bottomed holes has a reverse-tapered shape, which has, between an opening portion and a bottom portion of each of the bottomed holes, a bulged portion having a larger inner circumference than the opening portion. An adhesive is injected into the bottomed holes. An outer circumferential surface of the bonded portion of each of the side brackets and an inner circumferential surface of an end portion of a center beam face toward each other with the adhesive interposed therebetween.