**Best Way to Replace Insulation Under a Mid-90s Double-Wide**

I’m updating a mid-1990s double-wide and have finally reached the underbelly insulation. At this point most of it is gone due to years of plumbing leaks, repairs, and small animals getting in.

Originally it appears the home used the typical manufactured-home setup: a large fiberglass “blanket” held up by the belly wrap fabric, with the HVAC ductwork running inside that enclosed belly cavity.

However, the HVAC system was replaced several years ago and the installer removed the original trunk line and installed a hanging main trunk below the home instead. (In hindsight I think this was a mistake, but it’s already done.) Because of that, the ductwork is no longer inside the belly cavity.

So now I’m trying to decide the best way to re-insulate the floor.

### My main questions

1. **Should I reinstall a full insulation blanket like the original design**, supported by the belly wrap?

2. **Or should I insulate between the joists** (batts or mineral wool) and then reinstall/replace the belly wrap to hold everything up?

### Materials I'm considering

* Rockwool/mineral wool batts (current preference)

* Fiberglass batts (faced or unfaced — opinions seem split)

* Possibly recreating the original fiberglass blanket system

### Moisture considerations

Moisture is my biggest concern.

* The crawlspace is **not encapsulated** and likely will not be professionally encapsulated.

* There **is underpinning**, which is currently uninsulated but may be insulated later.

* I **could lay ground plastic myself** to reduce moisture but probably won’t be doing a full sealed encapsulation system.

Given those conditions, I’m unsure whether **faced insulation, unfaced insulation, or mineral wool** is the better option.

### Insulation depth / R-value

I haven’t opened the belly wrap yet because it’s still cold out, so I don’t know the exact joist depth. Based on typical manufactured homes from that era, I’m guessing the joists might support around **R-19 batts**, but that’s just an estimate.

If reinstalling insulation between joists is the better route:

* Is **R-19 appropriate**, or is there a better target R-value for this application?

* Are there reasons **not** to go higher in a manufactured home floor system?

### Other context

* Original belly wrap will likely need replacement.

* Past plumbing leaks are fixed.

* Animal entry points are being addressed.

I’m mainly trying to balance **moisture control, durability, and ease of installation** while avoiding mistakes that could cause mold or trapped moisture later.

I live in East TN. Jan-Feb are the coldest months ranging from 10-39 degrees the majority of the time with a few days or a week in the single digits. Summers can hit high humid 90's for July-August.

Any advice from people who have redone mobile/manufactured home underbelly insulation would be appreciated.

I have tried to provide what information I though might be needed. I realize I probably missed some and am happy to make up for my short falls.