I think that fits the bill! In fact I just looked at my hot water tank and the pad that it is sitting on has plenty to spare. Thanks, Camille

hi you could try glass fibre ceiling insulation itworks very well it is used a lot here for lagging home hot water cylinders and does not hold moisture.i dont know about over there but it comes in different thickness,s here

The heater core came with some sort of padding around the perimeter to keep it in place. 1 piece is still usable but the rest needs to be replaced. Any idea of what they used. Or something that does not hold moisture? Thanks again. You have all been SO helpful. Camille