This is Astrofoil 'TUFF STUFF'  so called because it is strong inought to take a 300mm (1ft) thicik reinforced concrete floor slab over it, you can walk on it with hobnial boots without permanetnly compressing the air bubbles.  it is TUFF, STRONG and last the life of the building!

It is lined with foil on one side ( the upper side) and comes  in two versions, single layer air bubble and double layer air bubble.

* Astrofoil Tuff Stuff * for use under concrete floors 20 m2 - Now 40% off Reflective Foil Bubble Insulation for underneath concrete floors including heated floors, £78.00

Astrofoil Tuff-Stuff, Reflective Foil bubble insulation for underfloor heating. 40m2 Reflective foil bubble insulation, extra strong for use underneath concrete floors, especially designed for use with underfloor heating systems. 40m2 roll 1.2m wide. Single bubble and double bubble versions available £120.00