Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.
Floor insulation water barrier section.
Vapor barrier goes on the warm in winter side.
When warm moist air from the living space reaches the colder metal of the van walls it condenses into water and gets trapped potentially causing rust and other problems over time.
The best option under a concrete slab is foamular 250 which delivers r 5 per inch of thickness along with 25 psi of compressive strength.
Reflectix and similar reflective radiant barrier products provide almost no insulation under or on top of a concrete slag just r 1 for reflectix.
This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses.
So this is clearly an ineffective solution.
2015 irc iecc air barrier and insulation installation table r402 4 1 1 n1102 4 1 1.
For alternative construction assemblies see section 150 1 c 1a b and c.
To keep this from happening you need to install a vapor barrier between the insulation and your living space so that moisture can t even get to the metal walls.
5 the orientation of the vapor barrier depends on the home s location and climate.
You could put batts too.
In any case the vapor barrier must point to the warm side.
Pipe insulation duct insulation and water heater jackets.
Breaks or joints in the air barrier should be sealed.
Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture.
If you don t want to use number 15 asphalt felt you can use some other approved water resistive barrier wrb.
Insulates ducts that pass through cold attics.
Around objects that store or distribute hot water and indoor air.
Continuous air barrier 2 confirm that construction documents specify a continuous air barrier for the building components associated with the insulation of the exterior floor s.
Up against the floor.
In most parts of the country the vapor barrier should face upward.
The code requirement calling for walls to be covered with number 15 asphalt felt is very odd because every manufacturer of asphalt felt declares unequivocally.
2 u factors can be met by cavity insulation alone or with continuous insulation alone or with both cavity and continuous insulation that results in a u factor.
The code requirement section r703 2 includes a qualification.
1 the u factors r values shown for ceiling wall and raised floor insulation are for wood frame construction with insulation between the framing members.
Usually composed of a thin film such as polyethylene vapor barriers are used to retard or prevent water vapor diffusion into a wall ceiling or floor during the cold winter.
Use insulation hangers wire staves spaced every 12 to 18 inches to hold the floor insulation in place without compressing it more than 1 inch.