by Mark F » Mon 19 Jun, 2017 9:04 pm
I have purchased approximately 3mm ccf from Clarke Rubber in the past. Use it in winter as a floor in my tent and have made a couple of cozies for my pot with it. Will have drag it out and weigh it. Given that a Cascades Designs RidgeRest with reflective face 15mm thick has an R of 2.8, 2.6 without the reflective facing, and weighs 540 grams 3mm ccf will add a little but not much.
Note that the underlay mentioned in a post above says "LOW thermal resistance" which means little insulating effect and "ideal for use with underfloor heating" - it lets the heat (cold) through. Cold is just heat passing in the opposite direction.
"Perfection is attained not when there is nothing more to add, but when there is nothing more to remove".