Insulating existing wheel house floor

[JSK76]

Got a great deal on an Empire heater with thermostat and it's a bit smaller then what I was running so I decided to insulate the floor to help it out. What's the best way to fasten it to the floor? I have a steel frame and I will be insulating about 12, 2'x3' sections. I will be jacking the house up and going in from underneath. I was thinking of glueing the foam in with PL 400 and maybe under sizing the foam 1/4" all around then using greatsuff spray foam around the gap. The frame is 3" high and I'm thinking of using 1" foam do I use foil backed foam to help slush and ice not stick or is non foil fine? I do block the frame but I keep envisioning me cranking up my house to move it and seeing all the foam stuck to the snow and slush. Not even sure if ice will stick to foam??

[BigDogRob]

I don't know if you are going this route because it is cheaper, but if you don't want to spray foam the whole floor then I would sandwich the foam with another same sized chunck of marine grade plywood just to ensure strength and stability I would be careful on just shooting foam on the outside edges due to the difference in open cell and closed cell foam! Open cell will soak up water and we all know that when water freezes it expands with great strength...thus it could blow the foam pieces right off the floor or break them into chunks, and losing the insulation factor.

Just my thoughts on it... I know my cousin had his floor sprayed for under $200. To me well worth the price!