25mm/28mm high density foam

[fastolfrus]

Not sure what the stuff is called, but I picked up a few offcuts of very high density blue foam at a wargames show a couple of years ago.

Absolutely great for so many uses, but where (in the UK) can I get more?

If I must buy it online what's it called?

[Sinewgrab]

Insulation foam is what it is mostly used for here in the US.

[Flinty]

I think (in the UK) the blue foam is XPS and tends to be used for flooring, so the cheapest source is the supplier/builders merchant. Google XPS floor insulation and you can find quite a few suppliers of pink as well as blue 1200mm x 600mm boards.

Worth noting that floor insulation is frequently thinner (5-10mm) and therefore cheaper than the thicker cavity wall boards, and you can source floor insulation that has higher compressive strengths - slightly less damage from dings, dents and elbows. Probably worth a trip to your local Wickes/Jewsons/Travis Perkins to see what they have and its what you want.

You can buy blue 'craft foam' from this lot, as well as a wide range of other types - https://www.panelsystems.co.uk.
Excellent service and pre-cut into possibly more useful sizes (as opposed to a 1.2m x 2.4m sheet) but obviously the craft version is more expensive than straight insulation. 

Word of warning, I personally found it almost impossible to cut large sheets at home and end up with flush edges; boxing them in with wood would take me ages and cost a lot more than I planned, so I ened up with enough hills and cliffs to make the Himalayas - not quite what I set out to do.....

 

[fastolfrus]

Thank you