The cushioning preform comprises two layers of foam material, e.g. polyethylene foam, laminated together in a laterally offset relation to one another, with or without a polyethylene film therebetween. Each of the foam layers is of rectangular cross-section has a surface section of greater density than the remaining section thereof. Rolls of the preform may be unrolled into a flattened condition on a substrate, such as a concrete floor, with a stepped edge of each unrolled preform overlaid by an adjacent unrolled preform and adhered thereto by a glue on the stepped edge.