In addition, a vapor barrier should be installed on the side of the insulation that remains warm in winter, especially if the outdoor temperatures average 40 degrees Fahrenheit or below in the coldest winter months and the relative humidity within the house is a constant 50 percent.
The trick with insulation is not to overinsulate, and that should be controlled by ventilation. The standard developed by the Federal Housing Administration is that attics with a ceiling vapor barrier must be ventilated with at least one square foot of vent area for each 300 square feet of ceiling. (Netting used to prevent pests from entering attic space is included in the equation.)
There are three kinds of vents-soffit, gable, and ridge. To help the process, some homes have turbine ventilators operated by moving air and attic or whole-house fans, which operate on electricity and are triggered by thermostats.
For added protection, ice-and-water shield can be installed at leak-prone areas of roofs. According to roofers, this water shield, which is another form of underlayment, is installed about two feet up from the edge of the roof.
However, W.R. Grace, the first company to manufacture the shield, suggests that certain leak-prone areas, such as the hip or a low-slope roof, require an application deeper than two feet. In addition, Grace recommends that the shield be installed on both sides of a valley, along rake edges, around skylights and chimney bases, and on the ridges.
Related posts:
- House Roofs Outside, on the roof surface, something else is happening, especially...
- Insulation at Your House (3) The facing material on the insulation is generally a vapor...
- Insulation at Your House (4) Whether you should install insulation yourself depends on the structural...
- Insulation at Your House A professional audit should be a detailed room-by-room analysis, including...
- Insulation at Your House (2) R-values are cumulative, so there is no need to remove...
health, home improvement, homeowner, house, roof, tips, ventilation