The builder insulated the upper 4ft of the basement wall with a pink batt style insulation which is held to the wall with a vapor barrier.
Vapor barrier concrete basement walls.
The vapor barrier is sealed to the concrete wall at the bottom with some sort of seal and nailed directly to the concrete.
Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls.
If you have a framed wall that is adjacent to a concrete foundation wall where the vapor barrier is next to the drywall in front of the studs the fiberglass insulation gets wet and becomes a breeding ground for mold.
The construction of the wall for instance is vital to the use of a vapor barrier.
1 on the interior wall between the heated and unheated portion of the basement i would not use with a vapor barrier.
A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed.
When the mold grows it will spread to.
Not to be confused with a vapor barrier which is placed on the warm side of the wall just in front of the insulation and behind the drywall a moisture barrier goes against the basement wall.
The main concerns are condensation and drying potential.
Also be sure to use treated lumber for the bottom plate on the wall framing.