How to Install Insulation on Exterior Walls the Right Way

Insulate your exterior walls with confidence using these helpful tips.

Stapling roll insulation

In exterior walls, kraft-faced fiberglass insulation helps control temperature and humidity inside the structure. It's important to have, no matter what weather conditions you live in, though the way you install it may vary. A well-insulated home keeps everyone comfortable and happy.

Of course, insulation also has a role in interior walls, and should not be dismissed when it comes to the rest of your home. You may want to add it to the walls of your upstairs area to help deaden sound between rooms. Below, we'll help you understand how insulation works and how to install it yourself.

Safety First

man fitting insulation into walls

One of the worst aspects of installing fiberglass insulation is that loose particles can be extremely irritating. Protective clothing is one line of defense: long pants and sleeves, collar and cuffs buttoned. Choose a dust mask specially designed to filter fiberglass particles. Thin leather gloves block irritants while still permitting you to handle tools easily. As soon as you've finished installation, take a shower, using cool water at first to close your pores so the fibers don't penetrate your skin. Wash work clothes in a separate washer load, using hot water and an extended wash cycle.

Another way to avoid discomfort is to select insulation that's designed to minimize itching. One product utilizes curled fibers that are less likely to irritate, and another type sheathes the insulation in a plastic sleeve.

Fiberglass insulation comes sized to fit between studs that are either 16 or 24 inches on center. You can buy it in rolls or in batts that are precut to the length of stud bays. For sound control, the paper facing is not necessary but provides a convenient flap for stapling.

Facing in the Right Direction

man installing panel chamfer

If you are installing fiberglass insulation in outside walls, pay attention to the paper facing. The facing is a vapor retarder, meant to slow the migration of water vapor through the wall. If warm, moist air from inside a house travels through the wall, it will condense when it hits the cold sheathing on the outside. If the sheathing is damp from condensation, it eventually wets the insulation, decreasing its effectiveness. Damp sheathing also is prone to rot. If the outside air is warm and the inside air is cool, the process works in reverse, causing condensation on the drywall. If you live in a climate where you heat in the winter, place the paper facing the inside of the house. If you live where air-conditioning is used more often than heat, face the paper barrier to the outside of the wall.

Add Soundproofing

To add soundproofing, weave a continuous roll of fiberglass insulation between staggered studs, using insulation designed for 2x4 walls. Weave loosely to fill the cavity but tightly enough so you won't have to compress the insulation when you install drywall. When you reach the end of the wall, cut off the insulation. Weave additional lengths of insulation in the same manner on top of each other until the wall is filled.

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