Existing Wall Insulation for Minnesota Homes

Existing wall insulation doesn’t have to mean tearing apart your home. RetroGreen Energy’s injection foam method is the most technologically advanced process available in Minnesota. We can double your R-value in just one day, adding year-round comfort and significant energy savings.

As Minnesota’s exclusive RetroFoam dealer and a top 5 installer nationwide, we’ve completed thousands of existing wall insulation projects throughout St. Cloud, Minneapolis, St. Paul, and the surrounding region.

Why Existing Wall Insulation Matters in Minnesota

Your walls represent the largest surface area of your home’s thermal envelope. According to the U.S. Department of Energy, poorly insulated walls account for up to 35% of heat loss in winter and heat gain in summer.

Many Minnesota homes built before 1980 have walls that are either uninsulated or contain failed insulation that has settled, gotten wet, or was installed incorrectly. Even homes with existing wall insulation often have significant gaps and voids that allow air to move freely through the wall cavity.

Common signs your walls need insulation:

• Exterior walls feel cold to the touch in winter
• Rooms on exterior walls are harder to heat or cool
• You can feel drafts near outlets and switches on exterior walls
• Your energy bills are higher than neighbors with similar homes
• Ice dams form on your roof (often related to wall heat loss)

An energy audit with thermal imaging can reveal exactly where your walls are losing heat and help prioritize improvements.

Benefits of RetroFoam for Existing Wall Insulation

RetroFoam is specifically designed for retrofitting existing buildings. Unlike traditional insulation materials, it offers unique advantages for existing wall insulation projects:

• Complete cavity fill – Flows around wires, pipes, and blocking to fill the entire wall cavity with no gaps or voids
• Air sealing – Seals cracks and gaps as it cures, stopping air infiltration that bypasses traditional insulation
• No settling – Remains in place permanently, unlike cellulose or fiberglass that settles over time
• Non-expanding formula – Won’t bow drywall or damage your home’s structure
• Moisture resistant – Does not absorb water or support mold growth
• Lifetime warranty – RetroFoam is backed by a lifetime warranty on materials

How Our Existing Wall Insulation Process Works

Step 1: Recognizing the Problem

Most existing structures have a wall insulation problem. Old fiberglass batt, horsehair, cellulose, or balsam wool insulation has settled and allows conditioned air to escape into the great outdoors.

At RetroGreen, we examine your home or building to see where this is happening. The good news is that many times the existing wall insulation is loose enough that our RetroFoam can be injected to stabilize and double the performance.

Step 2: RetroFoam Application Process

When installing RetroFoam into your existing walls, we remove a single strip of siding to expose the exterior of the building shell, then drill a small opening into each stud bay. This allows us to inject RetroFoam into the stud cavities without having to tear apart your walls.

Since this foam does not expand, the chemical reaction is much different from the foam many people are familiar with. Those types of foam are petroleum based and are classified as an exothermic reaction that expands and gives off heat. Our RetroFoam insulation is a cold-setting tripolymer foam that does not give off gas, heat, or expand and blow off your sheetrock.

RetroFoam is a game-changing foam insulation material that completely fills wall cavities, adds major thermal resistance, and will not settle like traditional materials like blown-in cellulose or fiberglass. Both of those fibrous materials tend to settle over time which causes performance to decrease. RetroFoam stays completely in place at the top of the wall where you need it.

Once we finish injecting the RetroFoam, we cap the injection holes and reinstall the strip of siding, leaving no visible changes to your structure. You’ll notice the comfort, efficiency, and reduced sound in your house the same day.

Existing Wall Insulation for Any Siding Type

Injection Wall Foam

Panel Siding Injection (when siding can’t be removed)

Steel, Vinyl, Aluminum Siding

Interior Wall Injection Through Sheetrock

Brick, Stucco, and Masonry Walls

RetroFoam existing wall insulation works just as well for brick and stucco walls as it does for homes with vinyl, seamless steel, cement board, or half-log siding. The only difference is that we drill smaller, 5/8″ holes directly into the masonry for RetroFoam injection.

After adding the foam insulation, we fill the holes and repaint them with a custom-matched color. For stucco, we also hand-grind the texture to completely match your exterior wall.

5/8″ Holes Are All We Need

Other existing wall insulation products require much larger holes to install. Our 5/8″ holes are virtually invisible after patching.

What About Old Insulation Already in the Walls?

Many homeowners wonder if they need to remove old insulation before adding RetroFoam. In most cases, the answer is no.

RetroFoam can be injected into wall cavities that already contain fiberglass batts, cellulose, or other loose-fill materials. The foam flows around and through the existing wall insulation, filling gaps and voids while stabilizing material that has settled.

This means you get the benefits of both materials without the cost and disruption of removing what’s already there. Our technicians probe each cavity before injection to assess the existing conditions and adjust the process accordingly.

Complete Your Home’s Insulation

Existing wall insulation works best as part of a whole-home approach. For maximum comfort and energy savings, consider combining wall insulation with:

• Rim joist insulation – Stops heat loss at the foundation level where walls meet the floor system
• Attic insulation – Prevents heat from escaping through the ceiling
• Air sealing – Closes gaps and penetrations throughout the building envelope

An energy audit can help identify which improvements will have the biggest impact on your home.

Existing Wall Insulation FAQs