With that silver bubble wrap stuff? Be careful. I use it at work and it will keep blood products at 98.6 for a insane amount of time in a 70 degree room with no loss of temp. ( box consists of a cardboard box, a layer of plastic bubble wrap, layer of the silver stuff ) So we got the wise idea to line the lunch cooler with it. Stops heat loss, should stop heat gain right? nope nope nope
turns out the stuff is a radiant barrier.. NOT an insulation, in that sense its only R- 1 ( the same as 1 inch of wood).It ref to be effective it has to have a air gap between the thing you are trying to " insulate" and itself. so stacking it to fill a gap in the floor isnt going to help much. heat and cold transfer across it wonderfully Its works much better according to the manufacturer in Hot climates, then in cold where its a waste of money as insulation. It does so very nicely quilted in between fabric to make a " thermal" curtain.
In any case it's too late, I've already installed it in the trailer floor. I will give a report, later this summer, about how it handled cold summer nights in Alberta. If our butts freeze, we will know the reason why. 
atleast its filling a dead air space? the floor on mine isnt insulated at all. I plan on a layer of rubber carpet padding ( r -5) and some indoor outdoor carpet ( r-3). Its replaceable, cleanable. and down here? its cheep. 
If you think about it , sheets are finely woven and very strong , made to endure repeated washing , drying , pulling, stretching , kicking ... and “other things” 
Since we all know so much about Foams in general now , seems like we could come up with a good mattress .. That wouldn’t require a substantial “investment" , yet provide Comfort and support ... gotta’ sleep well for the next day’s adventures eh !!! 
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