so tonight i ripped the old carpet out getting ready to lay new carpet in this weekend question is the old underlayment looks like house carpet underlayment i should rip up the that pos underlayment???, i bought the fullunderlayment kit from cj ponys when i ordered the carpet

 

My current view on carpet.
Paint clean metal floor w/ epoxy primer.
I like epoxy primer because it does not trap moisture and easy to touchup.
Use sound deadining if you must; it will trap moisture.
Can use sound deadining on hump and thick floor mats.
I prefer breathable underlayment in low areas.
Pull carpet and inspect metal floor every few years.
Touchup epoxy primer as required.
I have to dye my carpet often.
Wish I knew type of carpet that does not fade; like new cars have.

 

Why not just post this question in your other thread instead of starting a new one?

If you have new underlayment, I would replace it.