What are the problems with spray foam Insulation?

Spray Foam Problems

For many homeowners looking to cut down on their energy usage, reduce the costs of their bills, and enjoy a smaller carbon footprint, spray foam insulation is a no-brainer. 

Spray foam insulation makes your home more thermally efficient, which means you need to use less energy to heat or cool a space. Insulation does this by preventing heat from escaping from your home in winter and entering your home in summer. 

Given that many of us burn fossil fuels in order to keep our homes at a moderate temperature, reducing the need to do so with insulation significantly reduces your carbon footprint as well as the costs associated with energy. 

But if you’re thinking about installing insulation in your property, you’ll face a key question – which type of insulation is best? One of the better-known forms of insulation is spray foam insulation, which effectively increases your loft’s energy efficiency. 

In recent years, however, the approach to spray foam is slightly more sceptical, with some problems with the insulation coming to light that homeowners should bear in mind before opting for this insulation material. Let’s dive into the issues with spray foam insulation as well as the benefits, price, and alternative options. 

What is Spray Foam Insulation?

Spray foam insulation – also just called spray foam or spray polyurethane foam (SPF) – does what it says on the tin. It’s a type of insulation that you spray into a space and the foam then grows in size, moving to fill any available spaces. 

Spray foam insulation is versatile and can be used in a wide range of areas in your home, including your roof, loft, walls, and floor. 

Open vs closed cell spray foam insulation

There are actually two types of spray foam insulation – open-cell and closed-cell. Closed-cell foam sets into a rigid solid material and tends to be a more effective insulator than its open-cell counterpart. It can, however, lead to the build-up of condensation if there’s inadequate ventilation in the space. 

Open-cell is less dense once set so it’s not quite as effective as closed-cell spray foam. While it tends to be cheaper, you’ll need to apply a thicker layer than you would with closed-cell, so the more affordable price is slightly offset by the fact you need to buy more of it. 

Open-cell insulation can also be used as a form of acoustic insulation, blocking out disrupting noises and soundproofing (to an extent) your home. 

Advantages of Spray Foam Insulation

Before we dig into the issues commonly associated with spray foam insulation, let’s look at some of the things this type of insulation does well. 

Fits small spaces

Spray foam increases in size to fill all of the available space in an area. That means if you use it to insulate an oddly-shaped or difficult-to-reach space, it will grow to fill all of the nooks and crannies. This makes spray foam insulation particularly effective at stopping hot air from escaping and keeping your house warm during the winter months. 

Noise reduction

Open-cell spray foam insulation in particular is great at reducing noise by providing a form of acoustic insulation. Whether you’ve got a noisy neighbour or want to soundproof the attic for instrumental practice, spray foam insulation is one of the best ways to do so. 

Prevents the entrance of pests

Pests, such as rats and bugs, often enter your property through small gaps and crevices. By using spray foam insulation to seal areas, you reduce the chances of them being able to enter your property, keeping it safe from unwanted visitors. 

Increases the sturdiness of your walls

Rigid spray foam can actually strengthen the structure of your walls, making them more robust. While this is true, it’s a happy side effect of spray foam insulation, rather than its purpose. 

If your home has structural issues, applying spray foam insulation is not an adequate solution. Instead, you’ll need to contact a builder or engineer. 

Doesn’t require 270mm of thickness

One common reason why homeowners opt for spray foam insulation is that they want to store things in their loft. Standard loft insulation should be installed with a thickness of 270mm which is often higher than the joists, meaning they can’t lay boards on top. 

Spray foam insulation doesn’t need to be as thick, with about 100mm of spray foam insulation being equivalent to around 170mm thickness of mineral wool insulation. As a result, many people can insulate their loft and use it for storage, too. 

Problems with Spray Foam Insulation

While spray foam is an undoubtedly effective form of insulation and it’s great at keeping energy costs low, there are some problems with spray foam insulation that shouldn’t be overlooked by any homeowner considering installing this type of insulation in their home. 

If you’re keen to go ahead with spray foam as a means to make your property more energy efficient, it’s best to consult with an expert installer beforehand to make sure it’s an appropriate insulation for your property. Work with Insulation Advisor today, and we’ll put you in touch with spray foam insulation installers near you.

For now, let’s look at exactly what issues could be caused by the installation of spray foam insulation in your property. 


While not necessarily a safety issue, there is one significant barrier to using spray foam insulation – cost. It’s more expensive than many other forms of insulation, which makes it infeasible for some homeowners. 

Plus, it must be installed by a professional, so there’s no option to save on labour costs by doing the installation yourself. If you’re looking for a more budget-friendly type of insulation, consider blanket insulation. 

Difficult to remove

Once it’s been installed, it’s incredibly difficult to remove spray foam insulation. While other insulation materials can simply lift out of a space, spray foam can’t, which can cause problems, especially if you’re unable to sell your house as a result of spray foam’s presence (more on that later…).

Harmful fumes are released during the installation 

Spray foam insulation is definitely not appropriate for DIY installation, nor is it particularly safe to be near during the installation process. Spray foam can emit harmful fumes while it’s being installed, so it’s best handled with extreme care by somebody with experience. 

Can reduce ventilation

As any expert will tell you, if there’s one thing that’s key to reducing damp in a home, it’s ventilation. Unfortunately, because spray foam grows to fill every crevice in a space, it can actually reduce the amount of ventilation in that space. 

This can lead to every homeowner’s worst nightmare – damp. Damp eventually translates to mould and can cause long-lasting damage to a property, even to its basic structure. It also runs the risk of decaying your roof timbers, which would be costly damage. 

Not eco-friendly

While installing any form of insulation is generally considered an environmentally-conscious decision, this depends in part on what type of insulation materials you choose. 

While spray foam does do a good job of reducing a home’s carbon footprint by reducing its energy usage, it’s not made out of particularly eco-friendly materials. 

If sustainability is a key concern for you, look into some types of loose-fill or blown-fibre insulation materials, which are specifically made from recycled materials. 

The Link Between Spray Foam and Property Prices

In general, installing insulation is considered to be something that has the potential to increase the price of your property. After all, buyers are always looking for ways to save money when they move in, and having insulation already installed is one of them. 

Plus, the energy-saving advantages of insulation are seen as attractive to people in the market for a new home. Unfortunately, spray foam insulation is somewhat of an anomaly. 

Due to concerns over the potential for condensation, spray foam can cause issues when you’re coming to buy or sell a property. This is because lenders want to take as few risks as possible, and the risk associated with damp rotting the roof’s timbers is a costly one. 

Some lenders refuse to offer mortgages on homes with spray foam insulation, while some surveyors will reduce the price of the property if they encounter spray foam insulation upon inspection. 

While the national spray foam industry is working with lenders and valuers to try and resolve this issue, there’s no clear conclusion yet. If you decide to go ahead with spray foam insulation anyway, make sure your installer provides you with all the necessary paperwork in case it’s needed in a dispute with the valuer. 

For now, you may want to consider opting for an alternative if you plan on selling your home in the near future. But if you’re less concerned about resale, then spray foam insulation can be incredibly effective at insulating your home and reducing your energy bills. 

Spray Foam Alternatives

If you’ve decided that the risks of spray foam aren’t outweighed by the benefits for you, the good news is that there are plenty of alternatives to spray foam for you to choose from. Here are some of the most common types of insulation and the benefits of each. 

Blanket insulation

Blanket insulation comes in rolls, slabs, or batts made from materials like rock wool, mineral wool, and sheep’s wool. Sometimes, blanket insulation is made from recycled or recyclable materials, making it especially sustainable. Blanket insulation is incredibly budget-friendly and you can also install it as a DIY project, making it popular with homeowners. 

If you do decide to install blanket insulation yourself, however, consider that you’ll need to measure and cut the rolls. 

Despite its affordable price, blanket insulation does offer improved thermal efficiency and some forms are even fire and water-resistant too, protecting your home from fires and issues like damp and mould. 

Loose-fill insulation

Loose-fill insulation is sometimes known as blown-in insulation because it’s blown into a loft space using specialist equipment. As a result of the equipment and expertise needed, loose-fill insulation is not suitable for DIY installation. 

Loose-fill can be made from fibreglass, cellulose, or rock wool, with all three materials having their own pros and cons. It’s also available in different colours. If you’re trying to insulate a space that’s unusually small or hard to reach, loose-fill insulation is a great option, making it particularly effective as a replacement for spray foam. 

Some forms of loose-fill can be recycled as well as pest, mould, and fire resistant for extra safety. 

Rigid insulation boards

When insulating a loft, you can choose to make a cold roof or a warm roof. A warm roof will allow the loft to be used as a living space, while a cold roof is ideal for storage spaces. 

Rigid insulation boards are cheap, water-resistant boards that can be used for creating either a cold roof or a warm roof, unlike some of the other options on this list. That’s because they can be fitted in different parts of your loft. Rigid insulation boards are effective and, in the case of a warm roof, can be covered with plasterboard to make the space more attractive. 

Blown-fibre insulation

Just like loose-fill insulation, blown-fibre has to be blown into your loft space using specialist tools. This is one of the most expensive types of insulation, alongside spray foam, so it’s not suitable for homeowners on a budget. 

This type of insulation is also perfect for insulating tight, hard-to-reach spaces because nobody physically needs to enter the space to install the insulation. Note that it should not be installed as a DIY project, but rather by a professional. 

Spray Foam Loft Insulation Problems Summary

Whichever type of insulation you opt for, finding a professional installer to carry out the insulation is a must. After all, insulation being poorly-installed is one of the main risks that can make it less effective. 

Finding a reliable installer in your area is easier than ever with our quote-finding tool, which connects you with contractors in your area and allows you to collect quotes for the installation service you require. 

To get a feel for the right installer for you, check out online reviews and testimonials and feel free to ask for qualifications or examples of previous work. 

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