Need advice on insulating floor before putting new plywood down

WE are remodeling one of our mobile homes, it is a 1980 12x65. We removed the dividers and kitchen cabinets so we could replace the floor in the kitchen and living room. What we have now is a 12x27’ open room with the presswood floor completely removed. The underbelly only had a 5 places that had been cut by the PO when plumbing repairs were done and we repaired them as well as ran new plumbing lines while the floor was open. For the most part over half of the insulation is in tact. We have several rolls of R19 paper backed insulation in our storage unit. Would that be ok to use? If so, which side would you face the paper to? When moving around some of the old insulation, it appears that there was a paper backing facing the underbelly material that is now stuck to the underbelly material. Would it be better to buy unfaced insulation and just fill in the missing and low areas or can we use what we have on hand? The underbelly is the material is not the board like material, it is the tarp like material that drapes under the entire home.

As the unit had a roach problem after the last tenants lived in it for a year, we are also planning on spraying before putting down the new plywood. Any advice on that would be appreciated too.

Thanks Anna

After having replaced an entire underbelly and insulation I have reached the conclusion that I will never do it again.

ln my case there was no paper backing in the factory insulation. But if there is for yours I don’t see why using what you have on hand in the same configuration would be an issue.

As long as the pad sheds water away from the home you should not have problems.

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Thanks for the help Jhuston. Another thought was to check with HD and see if their bags of blown insulation can be spread by hand to fill in low areas. WE did find signs of perhaps opossums living in the insulation a few years ago but all the signs were old. They created a super highway down the middle of the underbelly insulation. That is where I thought the rolls would work best and then the blown in scattered to fill in low spots. The city condemned 3 empty mobile homes behind out property two years ago and last year the bank foreclosed on two other areas a block away and demolished 15 other units, all of the animals ran to ours. We started had an aggressive campaign to eliminate the critters and have had little problem in the pas few months.

Assuming the insulation is to keep out cold as opposed to insulate for air conditioning.
You best option is the green Roxul insulation in the floor. In like most insulation that becomes permanently useless if it gets wet the Roxul allows water to pass through and dries to retain it’s full insulation value.
Rodents do not like the Roxul glass content.
The vapour barrier should always be on the warm side of the insulation. Paper back insulation has next to no vapour barrier unless each adjoining seam is glued, calked or taped. Plastic is the best choice for vapour barrier and all seams and openings must be closed with tuck tape.