New track - under astro turf materials

[mikeyscott]

For the various astro turf tracks round the UK what did you use as a base underneath the astro turf?

Anti weed membrane?
A small layer of scalpings which have then been compacted?

Got a track to redo and lay new astro on, but of course we want a smoother track, but sill not touring car smooth. As so people will know TORCH is currently excessively bumpy.

This is at TORCH, so if people want to help then please do so