Q: I own a house that was built in the 1930's which has one floor of living space, a basement, and an open attic with gable vents. It has roughly 4-6 inches of blown fiberglass insulation. It has no roof vents, vapor barrier, or soffit vents. I wanted to increase the insulation in the attic. Would I use blown cellulose or fiberglass batts, and need to remove the existing insulation and add a vapor barrier? Do I need to install plastic or styrofoam joist vents without having roof vents?

A: I doubt that removing the existing insulation and installing a vapor barrier would be cost effective in terms of the money you would save in heating and cooling costs.

If you have enough gable venting (i.e. approximately one square foot for every 1,000 square feet of attic floor square footage) you could just install blown cellulose or fiberglass insulation over your existing insulation, as long as you are sure it is not asbestos. (If in doubt about asbestos, consult with an insulation contractor for advice.) Blown insulation generally covers better in an existing house and is more economical - just be sure you get quotes by R-value - not in inches, as that will vary among many different products.

Also, be sure your quotes include the minimum depth in inches and number of bags to be used match the manufacturers specifications. Then relax and enjoy a warmer and/or cooler residence with fewer temperature fluctuations.

Please visit us as http://servicemagic.com and become a member (it's free). Let us help you find the ideal service provider to install new insulation for you.

Good luck!
Kathy Maynard