Expanding Foam Can Be Used as Insulation, Here's How


Can Expanding Foam Be Used As Insulation?

Yes, expanding foam can be used as insulation. Expanding foam can be defined as a two-component mixture composed of two materials that react when mixed. This causes the foam to expand and harden, providing an insulating material.


Expanding foam insulation can be applied to any surface that needs to be reinforced to prevent draughts and enhance structural integrity. Expanding foam became a valuable form of insulation due to its thermal properties and resistance to heat flow, otherwise known as R-value. The higher the R-value, the more effective the insulation.

The history

It was first invented in 1937 by a man named Otto Bayer, developed for initial applications of shoe soles and cushions, and later used as building insulation in 1979.

As expanding foam grew in popularity, new methods arose that simplified the installation process. Expanding foam was poured into crevices and onto materials, which, for upright applications, proved tricky. Spray foam insulation is a form of expanding foam that can be sprayed onto any surface at any angle, and at a much faster rate.

expanding foam insulation sprayed in loft

Types of expanding foam

Spray foam insulation is available in a wide range of densities and cell structure; open cell spray foam is low density whilst higher density foams are referred to as closed cell spray foam. This allows buildings, warehouses, boats and more to be insulated at the R-value most suitable to their needs.

The image below clearly illustrates the air bubbles within each variant of spray foam insulation.

Open cell section with more bubbles than closed cell section

How it works

Once spray foam is installed into an area, the material expands and hardens. The expansion creates many little air bubbles within the material and fills all corners and gaps, ensuring that there is an airtight seal.

Air is a good insulator for heat but can transfer heat through convection. These air pockets alone are not the reason why spray foam is so effective. Spray foam is effective because of the thin walls between each air bubble which makes it difficult for convection to occur. This material allows heat to get trapped in the air bubbles and not escape further.

Among the insulation properties of spray foam, there are other benefits that should not go unnoticed:

  • Sound-proofing
  • Environmentally friendly
  • No R-value lost overtime
  • Air leak prevention
  • Convenient application of the product

The different foams

Expanding foam insulation has been developed by various insulation companies. The two-component mixture has been changed and adapted; Icynene® spray foam insulation is now one of the most popular due to its environmentally friendly properties and effectiveness.

There are other expanding foam solutions on the market, such as polyurethane foam, with their own pros and cons. However, at Mass Foam System we strongly believe Icynene provides the best level of insulation.

Within each spray foam product, there are also the varying types that are mentioned above: open-cell and closed-cell.

DIY expanding foam spray

Spray foam can be but should not be installed by yourself. If you are enquiring about this for money savings, you will certainly do the opposite through a DIY installation. We strongly recommend this because of the related costs involved in a DIY procedure. Using expanding foam spray without the proper equipment or safety measures in place, such as an appropriate ventilation system, can cause the effectiveness of the spray foam to decrease or even cost you more money for repairs to damages involved. Read our full guide on DIY expanding foam spray to learn about the costs and dangers associated.

However, whilst expanding foam can be used as insulation, it should only be applied by a professional. Mass Foam Systems are professional Icynene® contractors offering spray foam insulation all over the UK. Get an instant quote for expanding foam or get in touch to request a brochure – call 0800 246 5051 today!

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People also ask...

  • How Much Does It Cost To Install Spray Foam Insulation?
    To be blunt, spray foam insulation generally costs more than your standard types of insulation such as fiberglass insulation. This is because of the advantages that spray foam has over Fiberglass. Spray foam insulation has options to choose from like open cell spray foam or closed cell spray foam. A perfect example of spray foam insulation would be Icynene spray foam... Spray Foam Insulation Costs
  • Is Icynene® Insulation Toxic?
    Put simply, Icynene® isn’t toxic, and it’s safe to use in domestic properties. Icynene® is 100% water blown and consists of water and isocyanates and is certified as environmentally friendly.  It is important that Icynene® installers are used to ensure the product is fully cured and prevent any health risks during the process. Once cured, the foam poses no danger whatsoever... Icynene Toxicity Guide
  • Should I Use Spray Foam Roof Insulation?
    Yes, as choosing foam insulation can improve the structural stability of your home, prevent drafts and moisture ingress, and ultimately save you money on energy bills. These are just some of the benefits of spray foam roof insulation... Should I Use Spray Foam Guide
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