Tim S coughed up some electrons that declared:

Ho hum: While I was looking to see if there was anything cheaper than
Marmox, came across this:

Couple of factual followups, for anyone reading this later from google...

I've just handled a piece of 10mm (ish) "Warmup" under-tile insulation
panel, down at Topps Tiles place. It appears identical to Marmox.

It is *very* robust. The surface is as hard as rock and the softer core foam
(it's foam rather than squidged white stuff like jablite) feels very robust
in the face of tearing or compression. I would have no qualms about using
this to achieve basic insulation under tiles - though I'd go for at least
20mm if practical.


http://www.floorheater.co.uk/

Just had a message back from an old friend in Sweden. This product is really
made by these people: www.floore.se

He says that he's checked and a couple of the big DIY sheds out there are
carrying this product, so we conclude it probably has basic credibility at
least. I'll follow up when i get my mitts on the sample I've been promised.

Cheers

Tim