Underfloor Spray Foam Insulation: Ultimate Guide

Underfloor spray foam insulation is the latest innovation in home insulation and comes in a variety of thicknesses and layouts to meet different housing needs. With its high R-value per inch, superior thermal resistance, and rapid installation time, spray foam is undoubtedly one of the best home insulation solutions available.

In this blog, we’ll discuss all you need to know about underfloor spray foam insulation.

Underfloor spray foam insulation

What Is Underfloor Spray Foam Insulation?

Underfloor spray polyurethane foam is a type of insulation that is sprayed or pumped into the floor’s opening. It is made up of a polymer that expands when it reaches a higher temperature, creating a comfortable insulating layer.

Spray foam is also commonly used to insulate the gaps between ceiling joists and between the roof deck and the walls of a house. However, underfloor spray insulation is sprayed underneath the floorboards in your home.

Spray foam insulation is an eco-friendly alternative to traditional fibreglass insulation. It doesn’t contain hazardous chemicals or form dust. It’s an ideal option for eco-conscious homeowners looking for an environmentally safe insulation solution.

When you purchase underfloor spray polyurethane foam, you get a polyurea product combined with water and polyurea. This polyurea is a polymer that’s been mixed with liquid polyurea and then sprayed under your floors.

The spray foam will expand and increase in volume. Then, once it’s in those gaps, it is reinforced with a polyurea coating to create a solid structural seal.

Benefits of Underfloor Spray Foam Insulation

  • Very High R-Value: Spray foam insulation has a higher R-value than traditional insulation methods like fibreglass. Higher R-value means it’s more effective in terms of insulating the home. 
  • Very Fast Installation: Underfloor spray foam insulation installation is done quickly and efficiently. It takes only a few hours to install the product thoroughly. 
  • Easy to Maintain: Spray Polyurethane insulation is a non-toxic product that is easy to clean and maintain. 
  • Versatile Application: The product can be used in unoccupied or occupied homes. It can be used in underfloors, roofs and crawl spaces. 
  • Durable: Spray insulation is made of a durable polymer that is resistant to moisture, mildew, and mould.
  • Long lasting: Underfloor foam insulation can be kept forever if looked after well. Even if you do not plan to stay in your current home forever, spray foam insulation is still a worthy investment because when installed properly, it can add to the sale value of your home when it comes time for you to move.
  • Out of sight: With the foam being sprayed under your floorboards, the foam is out of sight and out of mind. As the expanding foam underfloor insulation is under your floorboards, it will keep your floors warm and retain the heat. This effectively provides you with underfloor heating foam insulation.

How Does Underfloor Spray Foam Work?

Spray foam is the same technology that is widely used in commercial settings and industrial applications. A dispensing nozzle is used to apply the foam in a wide spray pattern. This ensures that the foam is applied directly under the floors.

A pump is used to force the foam under the floors. A pressure sensor keeps the pressure inside the cavity constant, preventing foam from seeping up out of the floorboards.

Why Spray Foam is a Better Product?

There are numerous reasons why spray foam is the best way to insulate your home:

  • No Caulking Needed: Spray Polyurethane foam requires no caulk. The foam expands and seals the underfloor by itself. 
  • No Drywall Damage: Spray foam doesn’t damage drywall. It creates a water-tight seal around the drywall, which extends the lifespan of the drywall.
  • No Flashing Required: Spray Polyurethane foam doesn’t require flashing. It expands against the surface, creating a water-tight seal. 
  • Flexible Design: Spray foam insulation can be used in a wide range of residential building designs. 
  • Ability to expand: Spray foam, unlike traditional insulation, has the ability to expand to ensure that there are no gaps under your floors, lofts or in your walls to make sure that no heat escapes from your home, giving you higher energy savings when compared to other types of insulation.

Spray Foam Underfloor Insulation Cost UK

Spray foam insulation can be relatively more expensive than traditional insulation methods, but this is because it is a premium product. There is a high initial cost; however, spray foam insulation will actually save you money in the long run.

This is because it stops your heating from leaking out of your home and consequently can save you up to 50% on your energy savings per month.

Underfloor insulation prevents heat loss through your floorboards, so it may be a good idea to have spray foam installed under your floors to prevent heat loss in the winter. You will notice a significant improvement in your home after installation, particularly if you have wooden floorboards.

In the winter, wooden floorboards can be extremely cold to walk across, but after insulation installation, you will notice that your floorboards will not be as cold to the touch as they once were.

You may be tempted to try some DIY underfloor spray insulation. Still, it is advised that you find an accredited insulation installer, as they are professionally trained in insulation installation and will not make any costly mistakes.

Is Underfloor Spray Foam Insulation Worth It?

Underfloor spray foam insulation is an excellent option for homes looking to save money and reduce their carbon footprint. It’s a fast and reliable way to improve your home’s energy efficiency and keep it comfortable while being environmentally friendly.

However, it’s important to note that while spray foam insulation is a great choice for reducing your energy bills, it is essential to ensure that it’s installed properly.


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