Chipboard over polystyrene

[TabsTheCat]

Hi

I need to replace half a chipboard floating floor due to water damage which is 18mm chipboard, on a membrene and then floating on 2 layers of extruded polystyrene which sit on the concrete sub floor.

The polystyrene layers are 22mm thick and 33mm thick which allow routing and supporting of water pipes above the concrete. Does anyone know where I can purchase polystyrene with these thicknesses?

I really don't want to lift the whole floor and replace with a different thickness as the other end of the room has kitchen cupboards.

Thanks in advance.