Underlayment to use with hardwood #green
Wondering what the opinion is on an underlayment for a hardwood floor. From what i understand the main reason for an underlayment would be to have Vapor retarder (not barrier!) to slow the water vapor (if any) from passing thru the hardwood to fast which could possobly cause cupping and other issuies. Please add or correct if i am wrong. Stackup: slab > 6mil poly > 1" polyiso rigid foam > 5/8 advantec. I think the advantec has a perm rating of 1-2 The question is do i need one? I was planning on using aquarbar "B" but the concern is the asphalt, are ther alternitives that are greener? should i be conerned with installing a petrolium product in my living enviroment? I know it is used alot for this but i don't know if there are any health risks.