The Vibro-Curb from Thybar Corp.provides mounting for rooftop HVAC units and has integral, vibration-dampening spring isolators that are easily accessed. Roofing may be completed at a later date without disturbing the unit. Minimum 90 percent isolation efficiency is achieved with the isolators, which are custom-sized and -spaced to accommodate the rooftop unit’s weight and center of gravity. A 2- by 4-inch wood nailer is provided for attaching roofing felts. The flexible 9-inch counterflashing provides a weather seal.