I have built walls in my basement. I put the walls against the poured wall. I have room for 3 1/2 inch insulation but I'm concerned about any moisture. Should I put in 2 inch insulation so I have a dead air space? I am putting up tongue and groove knotty pine on the walls. Do I need to have a vapor barrier? I have heard yes and no. Any opinions would be helpful.

I have a 26'X32' bungalow with 3 telepost supports spaced 8' apart along the center of the 32' basement length. To eliminate the telepost which is in the middle of the 15' wide basement rec. room I want to place steel channel iron on both sides of the main support beam (beam is four 2'x8' supporting the floor joists). These steel supports would go from the outside cement wall to the second telepost 16' away. Then I would remove the telepost, which is only 8' from the outside wall. This would open up the center of the 15' wide rec. room. The main floor above the telepost I wish to remove is open space with no supporting walls. The roof above this first floor is also supported with a truss rafter running along the 26' length of the house. Will I get a spongy effect when walking on the main floor in the area of the removed telepost? Any advice about this or any other complication would be appreciated.