I have a 10 year old modular home with a poured concrete foundation that has been insulated with exterior foam insulation below grade and foam insulation with plastic sheeting below the 4" concrete floor. the basement is dry and reasonably comfortable year round
I want to create a basement apartment with steel studs and would like to knw what additional insulation I should use?
If I use blown insulation shoud it be blown on before or after I frame and would 1-1/2" studs be suitable?
Don't put batt or blown in insulation against the concrete walls or floor. No moisture barrier on the inside; you already have a moisture barrier on the outside. (The plastic sheet under the floor is a moisture barrier.)
Typical insulation requirement for the below ground portions of walls is R-13 which may have been satisfied with the foam already in place. Check your local building code (may be the standard International Building COde).
Tornado victims: Do not rush to rebuild. Take your time and look for and get a good contractor. Or consider selling the property and moving to a home that is ready to live in.