[HowieE]

Originally Posted by rlindberg

I'll pull the insulated that's in there out and put new in since I'll have a nice access hole...

There is no way you can install effective insulation through an access hole. Insulation has to COMPLETELY COVER any effective surface. Any void around the edge is just the same as no insulation at all. To replace the under belly insulation you need to remove the belly skin and work from the bottom. Now that said it would be impossible to install fiber glass insulation from the bottom since you have no way to support it in place. The factory lays the insulation in from the top and uses the frame members to support it. To reinsulate from the bottom you would almost be limited to spray on material. The proble,m there is any water that finds it way to the floor will be trapped there and rot the floor.