R-values for walls represent the sum of cavity insulation plus insulated sheathing if any. If the insulation has a facing or vapor retarder it should face inward see Exterior Wall Insulation. A Chart Showing R Values By Zone And Area Of Home Dallas Zone 3 Types Of Insulation Insulation R Value Blown In Insulation The basement walls need to be insulated to a minimum value of R-10 for continuous insulation such as foam plastic insulation or R-13 for framing cavity insulation based on the component requirements of Table N11021 Insulation and fenestration requirements by component. Insulation for basement walls r value . See the Department of Energys DOE ranges for recommended levels of insulation below. R-15 CodeBord FoundationBasement Walls. Best R Value Insulation For Basement Walls. Ours cost about 20 a roll and covered almost a 4 x 8 space. If you plan to finish the. For unfinished concrete walls there are several options. OtherThere are other forms of insulation...