Once insulation gets wet, it's hard to dry it out. “It will sit there like a sponge, leading to mold problems and rot,” says Tom. Vapor barriers—sheets of plastic or kraft paper—keep water vapor out of the wall cavity, so the insulation stays dry. Not every type of insulation needs a vapor barrier.
After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.
Vapor barriers are not required on both sides of insulation. They only need to be installed on the side of the insulation that faces the exterior. A vapor barrier provides a way to protect the integrity of your home. It keeps moisture out of the wall cavity and protects the insulation from getting wet.
After the insulation is installed, it is necessary to cover it up with a vapor barrier so the glass fibers are not inhaled. The best vapor barrier to use is roll of plastic sheeting. This vapor barrier is easy to install and does an excellent job.
If insulation is disturbed, especially fiberglass insulation, it can cause a slew of health problems. Plastic sheeting protects builders and residents from toxins, fumes, and air particles in dust that could irritate eyes, ears, and lungs.
Experts advise builders against the installation of an interior polyethylene vapor barrier unless they are building in a very cold climate — for example, in the colder regions of Canada and Alaska.
“Without a vapor barrier, concrete will deteriorate much faster through water vapor intrusion which degrades the quality of the concrete over time and can lead to foundation and building failures, like Surfside Condominium Collapse in Miami, Florida,” says vapor barrier plastic sheeting expert and Americover account ...
"Fiberglass insulation should never be left exposed in an occupied area, according to the American Lung Association," says ALA's Godfrey.
The Dangers of Exposed Insulation
Undisturbed fiberglass insulation is safe … but disturbed fiberglass insulation can cause a host of health problems for occupants: Interacting with exposed fiberglass insulation can release glass fiber particles into the air that act as lung, eye, and skin irritants.
It is ok to do this regardless; however, if this insulated wall is an exterior wall, the vapor barrier should be on the warm side of the wall. For an interior wall, it is not necessary, unless there is unusual humidity on one side, in which case the polyethylene should be on the high humidity side.
Fiberglass insulation cannot fight the battle against moisture intrusion alone, however. Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture.
Vapor barrier materials are installed on the warm side of the insulation in a building assembly, as determined by climatic conditions. In warm climates, it will be on the exterior and in cold climates, it will be on the interior.
Now, the questions asked here is that old attic insulation removal necessary? Not necessarily, however, as we mentioned above, old fiberglass attic tends to grow mold and attract insects. If there isn't any water damage or signs of insect or rodent-infestation, you can get by not having attic insulation removal done.
The secondary function is that it stops the infiltration of cold air from coming through the wall cavity into your home. Poly should be used on the warm side of any building surface of which is insulated such as insulated ceilings,walls and floors.
Suggestions for covering exposed insulation include working with an insulation expert to ensure safe, code-compliant results, installing plywood flooring over the floor, installing sheetrock or paneling over the walls and sealing the insulation by stapling a polymembrane sheet on top of it.
If the basement walls are insulated from the outside, a vapor barrier is not required. Otherwise, it can be dangerous as it can trap moisture in moisture-vulnerable areas.
Thermax's™ fire rating allows it to be installed in interior spaces such as basements, attics and crawl spaces without an additional thermal barrier. White Finish Thermax™ offers a finished look without the need for additional covering or paint.
In most situations, touching the material without proper protection will result in a sharp stinging, burning and itching sensation. The good news is that skin irritation caused from touching fiberglass tends to go away, but the bad news is that it can last for days if you continue to wear the same tainted clothes.
Code requires foam, paper-faced, or plastic vapor barrier-covered insulation be further covered with a fire resistant barrier. Wall board is commonly used because it cheap and easy, but for residential work, plywood, OSB, or other similar coverings can be used for added durability (in a garage shop for example).
Tests have shown that these laminated boards can withstand UV ray damage for a reasonably long time. That said, it's still advisable to cover any foam board insulation exposed to the Sun within 30-60 days at the most. On most projects, that's more than enough time to finish the exterior walls.
ECOCELL Blankets can be left exposed or even painted. Unlike other insulation materials, ECOCELL does not have to be covered with gypsum board. Leaving ECOCELL exposed is another reason ECOCELL is the cost effective solution for insulating basements and crawlspaces.
Not all plastic sheeting materials can be considered a vapor barrier for walls and ceilings. Builders using plastic sheeting must meet certain requirements for this application: Standard 6 mil thickness polyethylene plastic sheeting.
Unfaced insulation is great for new construction, remodels, walls, floors, ceilings, basements, attics and crawlspaces. It's best used for interior wall applications that do not face the outside and also in rooms that don't need moisture control, like living rooms, dining rooms and studies.
Interior walls that may need vapor barriers are those surrounding humid areas, such as bathrooms, where moisture can seep through the walls and cause damage. If you have an indoor hot tub or pool, it is critical to surround those areas with proper vapor barriers.
The majority seem to agree that insulated, unheated garages, should be allowed to breathe. If the garage is heated, you will need a vapor barrier, otherwise you will get frost and mold.