01/24/2026
I run into this often, so here’s a PSA for ensuring your insulation is properly installed.
The paper on insulation is not to help you staple it to the joists or studs. It serves a very important purpose. The paper is called a V***R BARRIER.
The v***r barrier is always to be installed against the living space. In the case of a crawlspace or unfinished basement, the v***r barrier should be against the floor above, and the raw insulation facing outward towards the basement/crawlspace.
A quick explanation…. The living space above has conditioned air. Whether it’s heat in the winter or cooling in the summer, it’s conditioned air compared to a cooler darker basement year round. This creates CONDENSATION between the main level floor and the basement area. Insulation helps the efficiency of the home by protecting that conditioned space from the non conditioned air in the basement, helping you maintain desired temperatures
The v***r barrier properly installed against the flooring or living space protects the insulation from that CONDENSATION and keeps it dry so it can do its job of insulating the floor.
Installed improperly, and the insulation is now a SPONGE to the condensation. Absorbing it and holding it, reducing its ability to insulate and creating a perfect environment for MOLD growth.