Installing Fiberglass Batt Insulation

For homebuilding pros and amateurs alike, installing fiberglass batt insulation probably sounds like a piece of cake (in relation to electrical wiring or plumbing, that is.) However, not taking the application seriously may sabotage the effectiveness of your home's insulation. Installing fiberglass batt insulation requires a very careful approach to ensuring a consistent installation without gaps or compression.

If we think of a home's insulation like a coat in winter, we can see how gaps will sacrifice overall comfort. A hole in your coat where cold air can get in and warm air can get out won't keep you comfortable, just like gaps in insulation will cause a room to be less comfortable. And when we get too cold, most of us will simply crank up the furnace, which uses more energy. The same goes for adjusting the air conditioner in summer. To help keep energy bills in check and be comfortable, it's critical to ensure there aren't any gaps in the insulation.

By paying close attention to just a few techniques, even a beginner can install batt insulation properly. Follow these steps:

1. Determine the size of batt and R-value needed for the wall.
2. Cut slits in the batt so that it fits snugly around any obstructions in the wall, like plumbing pipes and electrical wires. When insulation is stuffed into a cavity that has obstructions, gaps are created behind the pipes or wiring and can reduce the R-value of the insulation.
3. Batt insulation is available unfaced or with a facing already attached. The facing material is generally a vapor retarder that helps resist the movement of moisture vapor to cold surfaces where it can condense. In hot, humid climates (like the Gulf Coast), vapor retarders may not be needed. Check local building practices and/or building codes. If you're using unfaced batts, simply press the batt into the cavity. Make sure that the batt completely fills the cavity but don't shove it in. Compressing fiberblass batts will reduce its R-value.
4. If you're using faced batts, stable the lip of the flanges to the face of the wall stud every 8 to 12 inches from the top down. Pull the flange down as you do so, to eliminate any gaps. The kraft facing should face the warm side of the wall and should be flush with the stud so that there aren't any penetrations.
5. Make sure staples are hammered flush with the stud. This will eliminate bumps at the studs and will help ensure the drywall application is smooth.