6 Tips for Installing Fiberglass Insulation in Your Walls

Fiberglass insulation is widely used to regulate temperature and sound in homes. It consists of fine strands of glass. The material is excellent for heating, cooling, and sound entrapment. The non-combustible and non-absorbent properties of fiberglass make it a cost-effective and practical solution for residential insulation purposes. When you insulate with fiberglass, you can enjoy a quieter and cleaner home.

Unlike blow-in insulation usually used for attics, fiberglass batts are used for insulating walls. This padding consists of long, panel-like forms that you fit into the studs or frames on your walls.

To insulate with fiberglass more efficiently, try out these tips.

1. Use the Right Tools

Fortunately, properly insulating your walls doesn’t require highly specialized tools. A utility knife, putty knife, straightedge, staple gun, and tape measure are sufficient instruments to get the job done. Be sure to have plenty of sharp blades for the utility knife on hand because they enable you to cut more accurately. Plus, using a dull blade puts you at a greater risk for cutting yourself on accident.

2. Understand Batt Measurements

Purchase batts that will give you the desired efficacy in insulation. This is called the “R-value.” A higher R-value requires thicker insulation, while a lower R-value uses thinner insulation.

If your wall frames measure 2X4, purchase batts that are 3.5-inches thick and have an R-11 or R-13 value. For 2X6 frames, it is best to use batts that are 4.5-inches thick with an R-19 value. Generally, interior walls use batts with an R-11 to R-13 value, while exterior walls use batts with an R-19 to R-21 value.

3. Fit the Space

The key to effective wall insulation with fiberglass is firm placement. However, do not compress the insulation, as doing so lowers efficiency. Instead, leave a 1/2-inch allowance for length and width when you cut the batts to ensure there is a tight fit.

Also be sure to fit the batts in snugly at the edges and corners. When the batts fit tightly in the stud cavities, it eliminates voids and gaps, enhancing insulation.

4. Electric Cables and Pipes

It is best to encapsulate electrical cables and boxes. You need to split the batt into two pieces from top to bottom so that it fits around electrical cables. Place one half behind the cable and the other half on top of the cable.

Be careful not to cut through the wires, as you could cause a fire or hurt yourself. If you do not split the batts to cover electric cables at the back and front, you’ll end up with voids in your insulation. When you encounter electrical boxes, trim the insulation so that it goes around the box with a snug fit. The same principle should be applied if you encounter plumbing pipes in the wall.

5. Windows and Doors

Do not overlook insulation of windows and doors as you insulate your walls. Cut thin strips of insulation and fill the gaps between the frame and opening of the window or door. However, do not pack in the insulation too tightly, as doing so will lower efficiency and may bulge the frame. Fill in the gap snugly.

6. Vapor Barrier

It is a good idea to install a vapor retarder for unfaced insulation (insulation that does not have kraft paper as a vapor barrier). This blocks water vapor from escaping in the room through the insulated walls. The vapor retarder may consist of some polythene sheeting that you drape over the walls once you’ve installed the fiberglass.

Allow an overlap of 1 foot. Staple the sheeting to the frames and cut to fit securely along the wall surface.