How Can I Get Insulation Inside The Walls of My Home?

Homes built in the St. Louis area prior to the 1970’s often did not have insulation in the walls. Why? There are many reasons, not the least of which is...we didn’t build houses with wall cavities for the purpose of installing insulation.

One of the big reasons we built homes with wall cavities was to manage moisture. A wall that is composed of two walls with a cavity in between allows for the outer wall to shed water before it reaches the inner wall. For any water that does make it through the outer wall, the cavity between the two walls would provide a place for the water to run off and for water vapor to come and go.

Then somebody got the idea to put insulation inside the cavities in order to stop the flow of heat in and out of the home. That was a great idea most of the time, unless it disrupted the moisture management. But that’s another story.

So how do I get insulation into my uninsulated walls?

While there are several methods, one great way to insulate the wall is to dense-pack the cavity between the inner wall and the outer wall. Dense-packing is a method where insulation is "blown" into the wall under enough pressure that it can’t settle. This is ordinarily done from outside the house, although it can be done from the inside.

For houses with siding, we remove one or more rows of the vinyl siding, drill holes through the sheathing into the spaces between the wall studs, insert a hose, and with the right pressure and technique, pack each cavity with insulation to a density of 3.5 pounds per cubic feet. This density can generally be reached by packing the insulation with a pressure of at least 60 inches of water column. As long as this density is achieved, the insulation inside the wall will not settle over time.

The type of insulation we use most commonly to dense-pack walls is cellulose. In some situations we use fiberglass, especially when dealing with lots of metal. We also look for all types of special circumstances, such as walls that are not sound enough to withstand the pressure, ducts in walls, knob and tube wiring, vermiculite, asbestos, moisture, pocket doors, exterior wall surfaces other than siding, and many others.

Improve home comfort with dense-packed cellulose in your walls

The dense-packed wall will now significantly reduce the flow of heat in and out of the home during both the winter and summer seasons. It will do so by stopping conduction of heat through the wall and by stopping the flow of air up and down the inside of the walls. When done properly, dense-packing walls with insulation can make a home much more comfortable and energy efficient.