Insulating Your Attic

Insulating your attic may or may not save you money.

If there is absolutely no flooring in your attic the first thing you will want to do is lay down some temporary flooring. I recommend a couple pieces of plywood that you can move around with you as you work. Now that you can get around, check to make sure that you have a sealed attic.

Check the chimney and any other roof openings. Check the ceiling below the attic for light box openings, or partitions to ensure no heat is leaking into the attic. Seal with sealant any holes, use weatherstripping around the attic door or insulation behind the attic access panel. The only ventilation you want is through soffit vents on the bottom and gable vents to let heat out through the top. Be sure when installing the insulation that you do not cover these openings.

There are two main types of insulation: Fiberglass or mineral wool batts and insulation rolls: 15” or 23” widths. Both fiberglass and mineral wool batts are fire and moisture resistant. They are available with or without a vapor barrier facing. The facing is made of foil or kraft paper. Some batts are wrapped in plastic for easy handling.

You can also get fiberglass in medium or high-density batts, which offer more insulation as they are thicker than standard rolls or batts.

Loose fill Insulation: Loose fill insulation comes packaged in bags. Loose fill is either blown with a machine or poured from the bag directly into the attic. Blowing in insulation is faster and offers better coverage. You can rent equipment to blow in loose fill, but most people hire an insulation contractor. Loose fill is better than rolls or batts for attics with irregular joist spacing or with many obstructions.

Loose fill is rated by R-value. R-value is the insulations ability to resist heat flow. The optimal R-value is in an old home is R-38, and in a new home is 44 to 50. R-3 is given for every inch of insulation already in your attic. So, if you have say, no insulation right now, then you need an insulation that’s rating adds up to R-38 in an old home and 44 to 50 in a new one. If you already have 4 inches of old insulation then you only need R-26 to make it optimal. If you have more than 6 inches already, then this may not be a cost effective way to save on heat.