Vapor Barrier On 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.

Vapor barrier on concrete basement walls.

The vapour barrier is more properly called a vapour retarder. Concrete is like a huge sponge which holds water and water vapor for years and years. Most jurisdictions require a 4 mil plastic sheet vapor barrier for basement walls against concrete. That is if the studs are going to touch the concrete wall.

It is designed to stop moisture in the form of vapour that is inside the house from moving into the walls and forming condensation or ice. The construction of the wall for instance is vital to the use of a vapor barrier. As the wall dries the water vapor leaves the concrete and tries to penetrate the insulation and wall. Or you can leave a 4 inch gap between the studs and concrete wall and probably get away with it.

It needs to dry and then stay dryto avoid flooring problems. Vapor barriers are used because while fresh concrete is poured wet it s not supposed to stay that way. Usually that is right behind the drywall. 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 and.

With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing. You should then use fiberglass insulation that has a vapor barrier between the studs with the vapor barrier facing in toward the living space. Of foam against the wall this should not be a problem in your climate. Building codes usually require a vapor barrier 4 mil plastic sheeting on exterior basement walls if the framing is attached to masonry or concrete surfaces or if the wood framing butts up against the outer basement walls.

So there is enough gap for air to flow. 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 insulation and barrier extend right up into the joists where they are heavy duty stapled to the joists and flooring on the main level. Basement insulation vapor barriers the trick with basement insulation jobs is in understanding where water vapor is being stored and where it s moving to.

If you ve ever had a problem with a basement floor or any concrete floor you know the kind of damage that too much moisture can cause.