Vapor Barriers: Clear Vs. Black Plastic

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Moisture affects a home's structure on a daily basis by causing wood to expand and contract with humidity. Home construction designs typically take this moisture factor into consideration by adding multiple wood floor joists that can withstand the movement. Newly installed wood flooring might not resist the moisture expansion and contraction as well as the structural wood. Vapor barriers are a practical choice for moisture control, available in clear and black color schemes.


Moisture Sources

Moisture permeates a home from a variety of sources. Ground water, near and beneath a home, can emanate from the soil because of extended rainy seasons. Surface water can flow beneath a home's foundation and remain trapped. Even moisture within the home, such as from mopping, can affect humidity levels. Many homes have crawlspaces beneath the structure where the floor joists and girders reside. This is a typical area for moisture entrapment. Moisture evaporates upward into the home's flooring, causing damage. Vapor barriers are typically installed over the soil in crawlspaces, preventing the soil's moisture from emanating upward.


Clear Vapor Barriers

Clear vapor barriers are typically constructed of polyethylene. The polyethylene is shaped in thin sheets, commonly sold in a roll form. The majority of vapor barriers are 6 mils (thousandth of an inch) thick, although 8 mil sheets are recommended by various wood flooring manufacturers, according to Wood Floors Online. A drawback to clear vapor barriers is their tendency to sweat. This sweat adds another moisture source to the home, affecting any installed wood flooring negatively.

Black Vapor Barriers

Black vapor barriers are available in rolls, adhering to the same thickness values as the clear vapor barriers. Black barriers are more effective at stopping moisture evaporation, compared with the clear barrier. The dark color impedes the growth of plant seeds that might reside beneath a home's crawlspace. Plants naturally exude moisture into the air, creating more moisture. In addition, any sunlight that enters the crawlspace cannot penetrate the black color, hindering the evaporation process within the soil.



Proper vapor barrier installation will prolong the life of the home's wood and wood flooring. The barrier's moisture control contributes to a more comfortable living interior, reducing the need to run expensive air-conditioners and heaters.



Amy Rodriguez

Writing professionally since 2010, Amy Rodriguez cultivates successful cacti, succulents, bulbs, carnivorous plants and orchids at home. With an electronics degree and more than 10 years of experience, she applies her love of gadgets to the gardening world as she continues her education through college classes and gardening activities.