WHIRLYGIG is a method of manhole riser installation that is lightweight, size accurate, installs in minutes. Simply place a WHIRLYGIG form on the manhole cone, trim the form to height/grade in a single pass with our Radial Arm Trimmer, place the manhole casting, check for accuracy and pour redi-mix. Product is made from quality monolithic thermoplastic form impervious to adverse environments and in combination with a concrete collar produces a “set it and forget it” solution.
