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Injection Foam Insulation: What Is It? How Does It Work?

If you’ve ever considered updating or even getting new insulation for your home you will have seen the myriad of products on the market. Learn more about foam insulation, what it is, how it works, and how it can save you money.
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If you’ve ever considered updating or even getting new insulation for your home you will have seen the myriad of products on the market. There are many different kinds of insulation fiberglass, cellulose, fiberboard, foam board, spray foam, injection foam, and the list goes on.

At Retrofoam of the Carolina’s we specialize in one area and that is foam insulation. Part of our mission is to make sure homeowners looking for answers can learn from our expertise. Today we’re going to focus on foam, specifically injection foam. What is injection foam? How does it work? What is it made of? Read on for answers to these and other questions you may not have even known you had.

What is Injection Foam?

 The simple answer is it is a non-expanding foam insulation that works as an air barrier and seals cavities (such as the stud cavities in existing walls) against air movement. Unlike conventional insulation materials like loose-fill cellulose, or fiberglass it doesn’t lose shape in the cavity. There is no settling, compression, or sagging over time. When it’s installed the injection foam fills the space including cracks and gaps.

How Does Injection Foam Insulation Work?

When you are using your furnace or air conditioner to heat or cool your home your insulation should keep the house’s temperature consistent without those systems working overtime. When it works properly your home’s comfort is maximized and your energy bills are lower. The heat transfer (conduction) and the airflow (convection)  both affect the comfort and energy efficiency of your home and how well your insulation works it will impact that. Traditional insulation types like fiberglass and cellulose are good at resisting the heat that is transferred through conduction whether that is from the inside out during the winter or outside in during the summer. However, those same insulations allow air movement into and out of your home through gaps in walls, electrical outlets, windows, doors as well as the attic, crawl space, and rim joist. This air leakage, or drafts, contribute critically to a home’s energy loss. Foam insulation works best to reduce this air leakage as it provides both an air seal and heat resistance. As an added benefit injection foam insulation also has sound dampening qualities helping to greatly reduce noises from the outside.

What is Injection Foam Made Of?

Although several companies manufacture injection foam insulation, you may have guessed this time we’re going to focus on Retrofoam brand injection foam. Retrofoam is a three-part resin injection foam and as stated before, it is specifically designed to insulate enclosed cavities. As the resin mixes with a foaming agent and water it transforms into a consistency similar to shaving cream. This foam, when injected into the wall cavities, will fill all nooks and crannies while still making way between wires, pipes, and any other obstacles. It even fills around existing insulation forming an air barrier that helps prevent energy loss and drafts through existing walls.

What is the Process of Installing Injection Foam Insulation?

Without needing to tear out sheetrock, or removing existing insulation injection foam is installed as the name implies by injecting it into walls. In most cases, the exterior walls can be insulated from the outside. Although the process may be slightly different depending on the exterior cladding it’s fairly similar. With vinyl or aluminum siding a band is removed around the house and a hole is drilled in each stud cavity. The foam is then injected into each cavity filling it and creating the air seal previously spoken of. Once the holes are plugged the siding is placed back in position. Brick exteriors are slightly different with smaller holes being drilled through the mortar joints into the stud cavities. After the cavities are filled the holes are refilled with mortar and sealed. If going through the exterior is not an option then the stud cavities can be filled from the interior of the home by drilling through the sheetrock. Although patching and repairing sheetrock after an interior installation is more labor-intensive and time-consuming than the exterior it is still faster and easier than completely tearing out drywall to try and install traditional insulation.

How Does Injection Foam Affect Home Energy Costs?

According to the US Department of Energy, creating a well-sealed envelope – the exterior walls, windows, and doors – combined with the right insulation can make a significant difference in cooling and heating costs. Air that leaks through the home’s envelope is a waste of energy and increases bills and as we’ve stated injection foam creates a great air seal for that building envelope.

Essential Buying Guide For Injection Insulation


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