Insulating an Existing Wall Cavity: A Comprehensive Guide

Are you looking for ways to insulate your existing wall cavity without having to remove the drywall? You're in luck! There are several options available to you, from spray foam and cellulose to injected foam and blown cellulose. In this article, we'll discuss the different types of insulation available, the pros and cons of each, and the best way to insulate your existing wall cavity. The most common way to insulate an existing wall cavity is by cutting holes in the siding and blowing spray foam or cellulose onto the walls from the outside. This method is time consuming, expensive, and can be a disaster if not done correctly.

Fortunately, there are other options available. Both injected foam and blown cellulose can be installed without removing the drywall. Foam injection insulation is similar to the individual cans of foam insulation that can be purchased at a home center, but on a much larger scale and much more efficient. Professional injection-foam installation is best, but some manufacturers offer moderately expensive DIY kits.

Foam insulation is probably the best modernization option to prevent wall damage. The foam injection process creates holes in walls that need to be filled, patched and painted. With a small hole that ranges from ½ to 2 inches, certain types of insulation can be injected directly into a wall cavity. The three main materials used to insulate existing walls are cellulose, open-cell aerosol foam and closed-cell aerosol foam.

Cellulose is made from recycled newsprint and comes in the form of a loose filler that can be blown onto existing walls until it is densely compacted, also known as cellulose in a dense package. We often use cellulose in modernization work because it can be densely packed to provide excellent thermal resistance. New cellulose can be retroactively added to a previously insulated wall that already has cellulose but that has settled over time. Although holes should be less frequent, they are slightly larger, about 2 inches in diameter.

Another benefit of cellulose is that it is normally treated to resist fire, mold and pests. Unfortunately, cellulose cannot be added to a wall that has already been insulated with fiberglass. To add insulation to any exterior wall, holes are drilled between the struts of the existing walls. Then, spray foam, cellulose, or another form of loose filler can be injected to fill the cavities in the wall.

Finally, the holes must be plugged and repainted to match the rest of the wall. Injected foam insulation is another great option for insulating walls without removing the drywall. There are several types of injection foam available, including the RetroFoam product we use. These materials don't require the drywall to be removed from your home. Cementous foam, which is applied like shaving cream but hardens over the days to a meringue consistency, requires a mesh on the studs to contain it. Polyicinene provides approximately R-3.6 per inch of thickness; closed-cell polyurethane, between R-6 and R-7; and cementous foam, R-3.9.Polyicinene can crack existing walls or leak and stain the floor.

Polyurethane is not stable when exposed to UV rays. Both closed-cell polyurethane and cementous foam are not flexible, so as the bolts expand and contract, gaps can open. Most of the United States requires R38 to R60 in attics and R13 to R15 in wall cavities for optimal insulation performance. We share different types of insulation so that you can select what best suits the interior walls of your home. Made of open- or closed-cell polyurethane (a plastic), or of special cement, this insulation is applied in the form of soft foam or foamy liquid, fills all the spaces and then hardens instead. A homeowner who wants to similarly take advantage of a renovation to modernize new or additional insulation has many options: plastics, fiberglass, shredded paper, even pieces of denim and wool in various forms. If the attic (or roof) of a house is already fully insulated, adding insulation to the walls may be the best way to reduce heating and cooling costs.

You can place slats or rolls between or above the ceiling beams, and also place them over any existing loose-fill insulation. This makes it an excellent candidate for insulating existing walls, especially walls where air leaks are known to be present, but it also means that it can leak into unexpected areas. You can also add insulation to existing walls without removing the drywall by cutting holes in the outer cladding. You can mix insulation in your house or you can stick with the same type of insulation that already exists. In a perfect world you could magically place insulation behind closed drywall and be done with it - but reality dictates that you have to cut permanently fixed drywall; remove screws or nails for drywall individually; insert insulation in roll R-13 or higher; hang finish and paint new drywall. You know that installing new insulation will help stabilize your indoor temperature year-round but you're worried about what that might mean for your finished walls. No matter which type of insulation you choose for your existing wall cavity - spray foam or cellulose; injected foam or blown cellulose - you'll enjoy improved energy efficiency as well as improved comfort levels throughout your home.