Is Spray Foam Insulation Safe?

Spray Foam Harm

Spray foam insulation is a popular alternative to traditional forms of insulation, such as rolls, batts, and slabs, made from materials like fibreglass. If you’ve considered installing spray foam on your property, you’re probably wondering about its benefits, drawbacks, how much it costs, and even whether it’s safe. 

We’ve got you covered, with our ultimate guide to spray foam insulation and its safety implications. Let’s dive in. 

What is Spray Foam Insulation?

First thing first, what is spray foam insulation? Spray foam insulation – also known by the name spray polyurethane foam – is a liquid insulation that sets to form a cloud-like, hard foam, which insulates your property. 

Spray foam is most typically found as an insulation material in lofts and cavity walls. It’s extremely effective at improving your home’s thermal efficiency, which means it stays warmer in winter and cooler in the summer. 

The Two Types of Spray Foam Insulation

If you opt to install spray foam insulation, you have two options – open-cell or closed-cell foam. A closed cell, as the name suggests, has a more closed, denser structure. As a result, it’s a much more effective insulator and works well at trapping heat and preventing it from moving through the foam. 

Unfortunately, closed-cell spray foam is equally as effective as not letting water pass through it, which means there’s potential for moisture to build up around the foam, leading to dampness and even mould and mildew. Thanks to its effectiveness at making properties more energy efficient, closed-cell insulation is also particularly expensive. 

In open-cell spray foam, the structure isn’t as dense and the material isn’t as hard once set. As a result, it’s not as effective as trapping heat. It is, however, cheaper, less prone to dampness and mould, and better for soundproofing homes. 

Why Install Spray Foam Insulation?

Here are just some of the reasons homeowners opt to install spray foam insulation. 

Reduce energy bills

Spray foam is an incredibly effective thermal insulator, which means it keeps the temperature of your home more consistent year-round. As a result, you don’t have to use your heating or air conditioning as often, reducing the cost of your energy bills. 

Slash your carbon footprint

Many of us use fossil fuels to provide our homes with an energy supply. Unfortunately, they’re notoriously bad for the environment. The good news is, when your home is more thermally efficient, you don’t have to use as much energy to heat or cool it, therefore reducing your energy usage and slashing your carbon footprint. 


All insulation is built to last, but spray foam in particular is extremely durable. If you install spray foam on your property, you can expect it to last a couple of decades, at minimum. 


Both types of spray foam insulation reduce the flow of noise in and out of your home, but the open cell is particularly effective. These soundproofing properties can transform your property into a quieter, more relaxing space to live in. 

The History of Spray Foam Insulation

For at least 50 years, there’s been a tradition of insulating homes for improved energy efficiency, but this push has increased exponentially in recent years. All new build properties now have to have a minimum thickness of insulation installed, as per recent regulations. 

Spray foam was mostly introduced in the 1970s and 1980s and for a short while became the go-to insulating material for homes and businesses alike. Spray foam was installed across properties into wall and floor cavities and attics. 

Unfortunately, a few years after its insulation, spray foam started to cause issues in homes. Some problems related to poor application (showing the importance of choosing the right installer) but others were caused by the spray foam itself. 

In some cases, the spray foam shrank and cracked over time, while in other homes, the fact that the spray foam was so airtight caused problems in the form of dampness. When left unchecked and unfixed, dampness can cause mould and mildew, which is not only harmful to human health but can even rot your roof timbers in the case of loft insulation. 

Is Spray Foam Insulation Safe? 

Spray foam is a slightly controversial insulation material – not for reasons of ineffectiveness, but for reasons of safety. Read on to find out the safety implications of this popular insulation material. 

Environmental and Health Issues

Spray foam isn’t a natural insulation material such as alternatives like sheep’s wool. Instead, it’s man-made with chemicals, some of which are harmful to human health. 

Isocyanates, for example, have been known to cause allergic reactions as well as irritation of the nose, eyes, throat, lungs, and skin. Spray foam can emit harmful fumes during installation, so anybody involved in the insulation process or the property while it happens must wear protective gear. 

Other chemicals in spray foam are considered harmful to the environment at large. While insulation in general is considered eco-friendly because it can reduce your home’s reliance on fossil fuels, spray foam isn’t made of incredibly sustainable products. 

If eco-friendliness is a key concern of yours, opt instead for materials such as sheep’s wool or cellulose. Spray foam has also been known to cause dampness, which is harmful to human health. If you have spray foam property in your property, it’s worth checking it regularly to ensure dampness isn’t present or developing. 

Spray Foam and Your Property’s Value

Not so much a safety issue but a cause for consideration is a potential impact on your home as a result of spray foam installation. As a result of spray foam use, some lenders may refuse to offer mortgages if your home has spray foam present and some valuers or surveyors might look to reduce its value, too. 

While the industries are working together to try and tackle this problem, it does mean spray foam probably isn’t always the best insulation choice if you plan on selling up within the next few years. 

How to Make Spray Foam Insulation Safer

If you’re set on installing spray foam in your home or business premises, here are a few ways you can aim to make the process as safe as possible. 

  • Choose the right installer. By working with a reputable professional, preferably a member of the National Insulation Association, you can ensure the spray foam is installed correctly.
  • Do not install spray foam in damp places. Spray foam has the potential to cause dampness in a property, so the worst possible course of action is to install it somewhere that’s already damp. If you must install spray foam, solve any dampness in the area before installation. 
  • Consider ventilation. A good flow of ventilation is key to making sure spray foam doesn’t cause dampness and mould issues. Avoid covering ventilation spots like air grilles and use a vapour barrier layer. 
  • Use protective equipment. Because the material can emit harmful fumes during the installation process, everybody present on the property should be wearing protective gear such as gloves, goggles, and a face mask. 

How Do I Find an Insulation Installer?

If you want to install insulation, spray foam or otherwise, the easiest way to find an installer tends to be online or via word of mouth – a friend or family with a recommendation. 

We have a simple-to-use insulation installer finder, which scours through all the trusted installers who cover your postcode so you’ll be able to access quotes ensuring you’re getting the best value for money. 

If you’re only insulating one part of the home, you can expect the insulation process to take no longer than one day, but if you’re insulating your whole home, it will take longer. Generally, the day rate for an insulation installer will be somewhere between £150 and £350, with prices being more expensive in the southeast of the UK. 

Take your time finding the right installer and make sure you work with a trusted contractor. After all, insulation can last your lifetime, so making sure it’s properly installed is non-negotiable. 

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