Vapor Barrier For Attic Cieling And Florida

For example installing a radiant barrier in an attic that already has high levels of insulation r 30 or above would result in much lower energy savings than in an attic insulated at a low level r 11 or less.

Vapor barrier for attic cieling and florida.

Whether or not you need a vapor retarder hinges on three main factors your climate your home and the location of the wall you re insulating. Whether using loose fill or batts put the vapor barrier closest to the warm side of your installation where hot moist air would get in facing the house s interior in cold climates beneath floor insulation and the attic s interior in hot climates on top of floor insulation. During the energy crisis of the 1970s a prevailing belief took root where it was thought that tightly sealing walls and ceilings with a vapor barrier was essential to blocking heat transference and reducing energy costs it was soon determined however that unless the seal was absolute moisture that did get into sealed walls could create serious structural problems and health issues such as. Rosemary june 5 2015 at 3 03 pm.

The amount of thermal insulation affects the potential radiant barrier energy savings. Except for very cold regions and in isolated cases where there is high humidity in the house during the winter attic vapor barriers aren t required provided the attic is sufficiently ventilated as a rule of thumb one square ft. Some regions don t require a vapor barrier. Fbc section 1203 2 newer studies newer ashrae studies have found that the practice of attic ventilation to be detrimental to structures in warm humid climates.

To know if you need a vapor retarder ask yourself a few basic questions. This acts as a barrier to keep heated moist air from rising up into the attic during cold weather. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. On the other hand an air barrier a properly detailed air tight drywall ceiling for example in the absence of a vapor barrier can be effective since it stops the flow of vapor laden air.

A vapor barrier in an attic assembly in a severely cold climate with the absence of an air barrier will likely be ineffective. Of vent opening is needed for every 150 square ft.