Vapor barriers work to prevent humidity and moisture from sifting through the environment to the insulation. Depending on the building code legislation in each state, and depending on the weather of each individual location, a vapor barrier might not be necessary for your building.

However, climates that are cold (or where it snows) and climates that are very wet (a lot of rain each season) will benefit from having a vapor barrier installer with the insulation.

What should you know?

On no shortage of occasions, our sales team has dealt with clients that are extremely confused after reading for hours without end about the different vapor barriers and the types of vapor retardants that are available for them in the market.

The first thing to clarify is that the term “vapor barriers” is the same as “vapor retardants” and, for some insulation specialists, the term “vapor diffusion retarders” is the same thing. Therefore, when you read any of these terms on the many websites that speak about them, do not feel overwhelmed or frightened because of them. They are all speaking about the same thing.

Putting it in a simpler manner, “vapor barrier” is the old term, and “vapor retardant” is the new term.

There are many materials that can carry out this function. Damage from water condensation can cause serious damage to any building structure and can even cause a thorough and well carried out insulation work useless as moisture sifts in through the wall and dampens the insulation material.

When there are no vapor retardant materials, there is nothing that prevents water from reaching walls, ceilings, attics, crawlspaces, or roofs. This causes that the resulting condensations become potentially severe and, in consequence, it will cause the building materials to rot or mold to grow.

In a natural process, vapor diffuses moisture into and through wall structures, which ends in the condensation on cool surfaces, this is a water vapor drive. Every human activity produces vapor; even though each activity produces a different amount of it. It will also release the vapor that you produce moving and enjoying your home indoors; then it will clash against the walls. However, condensation in the wall will be less during the hot months of the year in opposition to the colder ones.

So what exactly are vapor barriers?

Vapor barriers have a permeability that has several levels. This is the reason why they are referred to as “vapor retardants”. Vapor retardants or vapor barriers should, like anything else in your home, be checked for integrity and performance and replaced when there is an evident problem or the performance is less than acceptable.

Vapor retardant materials are categorized as:

  • Impermeable

Among these, you can find asphalt-backed kraft paper, elastomeric coating, vapor-retarding paint, oil-based paints, vinyl wall coverings, extruded polystyrene, plywood.

  • Semi-permeable

Here you can find polystyrene fiber-faced isocyanurate, heavy asphalt impregnated building papers and some latex-based paints.

  • Permeable.

Here you will be able to find painted gypsum boards and plaster unfaced fiberglass insulation, cellulose insulation, unpainted stucco, cement sheathings, spun-bonded polyolefin as well as some polymer-based exterior air barrier films

These vapor barriers are usually available in the market as either coatings or membranes. Membranes are flexible and thin, yet since they are so, they often need, -and sometimes include, thicker sheet materials that are named “”structural” vapor diffusion retarders”

Coatings on their own are like their name states, wet and are usually applied with a brush.

So do they work with any insulation?

The most popular insulation material is fiberglass. This is well-deserved fame since it is one of the most effective and popular materials today. Financially friendly and effective, it is also easy to install for both the contractor as well as the homeowner who likes to tackle weekend projects.

This type of insulation has two weaknesses:

  • It has an open structure
    It has Low density

These vulnerabilities are more dangerous when we add water vapor to the mix. Fiberglass insulation without a vapor barrier is prone to aid and assist in the formation or rot-promoting condensation, causing serious problems in the building structure, whether it is in the attic, rooms, or basement. This is the main cause why using vapor barriers is a construction mandate in building code specifications in certain states and locations.

The risk of rot-promoting condensation is a serious concern for homeowners. Even with the use of vapor barriers, this is a risk that should be calculated and weighed when installing them. In consequence, it is important that vapor barriers are installed in a continuous layer.

Installing the vapor barrier in a continuous layer means that it should NOT have cuts, holes, perforations, or any other disruption. Of course, installing a whole room in one single layer is not only very difficult, in most cases, but it’s also rather impossible.

Therefore, what is done is to “connect” or pair over one sheet on top of the other at strategic points. Some contractors prefer the corners as these already have sustentation, so it’s is easier to have the vapor barrier solidly fixed.

When installing a vapor insulation barrier, it will be important to adhere it to the studs where the insulation has been adjusted and then cover those puncture holes with proper taping or another form of sealant.

The best tactic against moisture problems also must include a tactic for sealing gaps, cracks, holes, and window sills, and door thresholds.

Customer Question

Are Vapor barriers, Vapor Retardants, and Vapor liners the same thing?

Yes, they are. Depending on the provider, vapor retardants and vapor liners are the way they refer to the films that are used to cover the insulation in its whole. However, there seems to be a concession as a potential “difference”: Vapor retardant barriers are “breathable” which means that -some air can flow through them; while vapor barrier liners are “not breathable” and as such, there is no airflow between them

But there is no truly “unbreathable” barrier in the market, they will all allow -some, at least. Still, they should be a part of a moisture control strategy at your home or business. Vapor retardants/barriers/barrier liners reduce the rate at which vapor can move through the material.

Such ability, as we have mentioned, is measured in units known as “perms”, which we have already covered in this same article.

Before you start with the insulation installation in your home, you need to check the building code in your location. According to the weather in your location, a vapor barrier might not be required.

Still, you might want to try and use the benefit of having a vapor barrier installed in your insulation. Reach out for assistance. Our paper-faced products might be the perfect solution for what you are looking for.

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