Can You Use Spray Foam Insulation As A Cavity Wall Filler?

Using spray foam as cavity wall insulation

Spray foam is a versatile insulation and sealing material that’s made up of two chemicals: polyol resin and isocyanate. When combined, these chemicals produce a foam that expands to over 100 times its original size and seals even the smallest gaps and cracks in an instant.

For this reason, spray foam is widely used to insulate residential and commercial buildings. Interested homeowners typically ask: Can you use spray foam insulation as cavity wall filler?

The answer is a resounding yes! You can use spray foam insulation to effectively seal floors, roofs, door frames, and walls, including your home’s cavity walls. In doing so, not only will you make your home a more comfortable one, but you’ll also lower your energy bills and carbon emissions.

Let’s take a closer look at how spray foam insulation works and how long it usually lasts. We’ll also explore more reasons why spray foam is an excellent choice for your home, your pockets, and the environment.

How Does Spray Foam Insulation Work?

Spray foam insulation works exactly how it sounds—a specialised spray gun is used to apply the liquid foam onto a surface. Before spraying, the chemicals are usually stored in separate tanks. Gas pressure transports the chemicals to the tip of the spray gun, where they combine.

The resulting liquid foam contains little pockets or bubbles, commonly called “cells,” that expand to fill the available space, including all the tiny nooks and crannies between your walls.

When the foam hardens and cures, it creates a solid and long-lasting layer of insulation that prevents heat loss, keeping your home warmer in the winter and cooler during summer. The foam also acts as an airtight seal that prevents air, pollutants, and moisture from entering.

Installing Spray Foam Insulation on Your Cavity Wall

The process of filling cavity walls with spray foam insulation may vary from one installer to another. Still, it often begins with preparing the cavity by removing dust, rubble, moisture, and other contaminants.

The installers will then drill small entry holes into the exterior of your walls. The holes follow a pre-set pattern, usually diamond-shaped, to ensure the even and continuous distribution of insulation between the walls.

The spray gun or pump injects the liquid foam into the cavities between the walls. As the foam expands, it rises and fills the cavity, including gaps, crevices, and irregular spaces. The end result is a solid, durable, and airtight layer that’s resistant to heat transfer.

The final steps involve restoring the cavity walls by filling up the entry holes and repainting the affected areas.

How Long Does Spray Foam Insulation Last in Your Cavity Wall?

Spray foam insulation has an estimated lifespan of 80 to 100 years, and it’s expected to last as long as your home or building. 

Most spray foam manufacturers offer up to 25 years of product warranty. Similarly, the Cavity Insulation Guarantee Agency (CIGA) provides guarantees for up to 25 years for cavity wall insulation that’s fitted by its registered installers in the UK.

Spray foam is among the easiest types of cavity wall insulation to maintain. Once installed, it’ll remain effective throughout the life of your home without requiring regular maintenance. As a result, you’ll be able to recover the initial cost of your insulation in a matter of years.

Benefits of Using Spray Foam Insulation as Cavity Wall Filler

Spray foam insulation has been around in the UK for over 30 years and is a top choice for homeowners and builders alike. Here are some key reasons why spray foam is worth considering for your cavity wall:

1. Consistent Warmth and Comfort

In a typical British home, around 35 to 45% of heat loss results from poor wall insulation. Other major sources of heat loss include windows, floors, and uninsulated roofs. Having well-insulated cavity walls will keep your home warm and comfortable, greatly enhancing your quality of life.

2. Lower Costs and Carbon Emissions

Since spray foam works so well at insulating your home, you won’t have to turn the heat on as frequently to regulate indoor temperature. This translates to high energy savings, lower heating bills, and a much smaller carbon footprint. It’s a win-win situation for everyone.

3. Soundproofing

Spray foam doesn’t just provide thermal insulation. It also adds acoustic insulation to your walls. It dampens the loud sounds that flow through your home, significantly reducing noise and creating a quieter and calmer environment.

4. Structural Strength

Did you know that installing spray foam insulation will improve the stability and strength of your cavity wall? Filling the cavity helps to reinforce the walls, making them more firm and sturdy.

Additionally, closed-cell spray foam insulation is considered a flood-resistant material, as it can withstand direct contact with floodwaters for an extended time. Some types of spray foam are also fire retardant, which means they can slow down the spread of fire.

5. Coverage and Durability

Spray foam insulation completely seals all cracks and crevices in your cavity wall, ensuring seamless insulation. Since there’s no opportunity for moisture to get in, the risk of mould and condensation decreases as well. 

Plus, spray foam is built to last for decades without sagging, settling, or compressing over time. Its longevity allows you to recover your investment through energy savings without having to worry about recurring repairs and upkeep.

Enjoy the Benefits of Spray Foam Insulation in Your Home

Installing spray foam insulation is an effective way of preventing heat loss and enhancing the energy efficiency of your home while reducing energy bills in the long run. However, it’s a complex process that requires planning, protective equipment, and proper techniques to be successful.

If you’re looking for a qualified and experienced installer to add spray foam insulation to your cavity walls, Insulation Advisor has exactly what you need. We’ll connect you with the best insulation contractors in your area and provide you with expert advice every step of the way.

To get started, click here to get your free insulation quote today.

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