How Long Does Loft Insulation Last?

Old Loft Insulation

Insulation is a must if you want to make your home more thermally efficient, environmentally friendly and cost-effective when it comes to heating bills. Loft insulation, in particular, is a common choice of insulation, especially because around a quarter of heat is lost through the roof space in an uninsulated home.

One thing to consider when making an investment for your home is how long loft insulation will last. You’d expect it to have longevity way beyond that of a typical household appliance for example. For loft insulation to deliver a good return on investment, you’d be looking for it to continue to perform well for several decades. 

For that reason, you’ll probably want to know how long loft insulation lasts before you go ahead with the installation. After all, in some instances, loft insulation can cost up to thousands of pounds, so if it doesn’t last long enough to make your money back from energy bill savings, it wouldn’t be a cost-effective option.

If you’ve been considering installing loft insulation in your home and you’re wondering how long you should expect it to last, we’ve put together a guide on types of insulation, its lifespan, and how to make it last longer. 

The Most Common Types of Loft Insulation

Here are some of the most common materials that could be used for insulating your loft. Each one has its own advantages and disadvantages, so it’s worth researching which is the best one for your property before getting started. 

Loose-fill insulation 

Loose-fill, as the name suggests, is made up of loose lightweight materials such as cork, mineral wool, or cellulose fibre. 

If your space is especially hard to reach, loose-fill is ideal, as it can be blown into nooks and crannies and small spaces by a specialist installer. Some varieties are even pest, mould, and fire-resistant, which certainly helps with longevity. 

One of the biggest disadvantages associated with loose-fill, however, is its propensity to blow around the space and settle, making it unsuitable for especially draughty lofts and those hard to reach areas. 

Blanket insulation

Blanket insulation is one of the most common loft insulation materials – and for good reason. Blanket insulation comprises rolls and slabs made from either sheep’s wool, rock wool, mineral wool or glass wool that can be installed to the recommended depth. 

It’s fire resistant, water resistant, and can in many cases be installed as a DIY project if you’re looking to save money on your insulation or replace existing insulation. This type of insulation can, however, break down faster than other types.

You can still definitely expect to get at least a few decades out of this popular insulation materials, though. Blanket insulation, such as mineral wool insulation and fibreglass insulation, tends to be more affordable both in terms of materials and labour cost, so if budget is a concern, too, this type of insulation might be your best option.

Blown-fibre insulation

As the name suggests, blown-fibre (also sometimes known as blown-in) insulation has to be blown into your loft space using specialist tools, making this type of insulation unsuitable for DIY installation. It’s perfect for getting into small lofts and filling all the gaps.

Blown-in is generally made from recycled materials, so if being more eco-friendly is a priority for you, it might be the best option. 

Insulation boards

Perfect for moisture control, rigid insulation boards are cut to size and then installed either over the joists of your roof or in between them. 

If you have a loft conversion, insulation boards are perfect because they can be covered with plasterboard to make them more cosmetically appealing.

Spray foam insulation

Spray foam insulation is a highly effective and is sprayed into a loft space and expands to fill it, insulating all the area it covers. While spray foam has traditionally been a popular option in the insulation industry, it can, in some instances, present some difficulties when looking to sell your property, or trying to obtain equity release or even remortgaging.

This good news is that these difficulties with spray foam insulation can usually be overcome, if you have all the paperwork relating to your installation to prove that it was professionally and correctly installed, and that your roof was in good condition at the time the foam insulation was installed.

How Long Can You Expect Loft Insulation to Last?

One of the biggest advantages of loft insulation is its longevity, so you won’t have to spend money replacing your insulation just a few years after it’s been fitted. The Energy Saving Trust asserts that most insulation has at least a 40-year lifespan, but in some cases, insulation lasts even longer. 

You can expect it to last for the majority of your time in the property. Plus, if you do come to sell your property just a few years after having loft insulation installed, you might be able to get a better price for it because the new owners will inherit loft insulation that will still be effective for decades to come. 

Obviously, how long your loft lasts depends on multiple factors, such as the material you use and the conditions in your home – we’ll look at these variables in the next section. 

What Can Cause Loft Insulation to Degrade More Quickly?

If loft insulation installed is looked after properly, it could last up to 100 years in some cases – certainly for as long as you can expect to live in the house. There are, however, a few factors to be aware of which can decrease the lifespan of your new insulation.

Loft insulation is likely to degrade more quickly when:


      • Excessive movement or weight damages it

      • The insulation is poorly installed in the first place

      • Pests and rodents move around the loft

      • There’s leaks in the loft space causing wet insulation

      • Excessive water and moisture has caused damp and mould 


    Loose-fill and blown-in insulation in particular are more prone to settling, too, which can make the insulation less effective in the long term and have negative impact on your heating bills. 

    It’s also worth considering that types of insulation that don’t tend to attract pests and don’t soak up water can last longer, so if the lifespan is a key concern for you, bear this in mind when selecting your loft insulation of choice. 

    If your loft insulation is easily accessible, it’s a good idea to check it either yourself or with the help of a professional every so often. 

    How to Make Your Loft Insulation Last

    Aside from avoiding conditions that would cause your loft insulation to degrade quickly, there are a few other ways you can make sure you get the longest time possible out of your loft insulation. 


      • Find a trusted installer. How well your loft insulation is installed in the first place will play a significant part in how long it lasts long-term. Finding the right installer is crucial, and we can help you with this. If you do decide to install loft insulation yourself (which is possible with blanket insulation), make sure you read a detailed guide to make sure you’re doing it properly. 



        • Consider damp. If your loft is especially damp, you have to take care with how you approach installing insulation. It’s worth considering whether the space is suitable for insulation at all, and if you decide (with the help of a professional) that it is, choose a water-resistant form of insulation. 



          • Fill all gaps. When you’re installing blanket insulation, it’s all too easy to leave gaps between the pieces of insulation and not think too much of it. The bigger the gaps between your insulation, however, the less effective it will be, so make sure you’re not leaving spaces through which the heat can escape. 

            • Get it checked. If your loft isn’t a space that you use or access regularly, it’s all too easy to install insulation then never think about it again. The issue is that while you’ve forgotten about your insulation, it could be growing mould, being chewed by mice, or simply becoming less effective. Check your insulation at least once a year (or call a trusted professional to carry out an in-depth check) to give you peace of mind that it’s in good condition and still working effectively. 

          Installing loft insulation -where to find an installer

          Part of the key to ensuring your loft insulation lasts as long as it should is finding somebody who will properly install it in your loft space. We can introduce you to trusted installers who can fit loft insulation in a way that guarantees longevity and savings with energy bills for many years to come.

          You can use our contractor finder tool to find a trusted installer in your area and access a quote for installing loft insulation. Look out for installers with positive reviews and testimonials and don’t be afraid to ask for examples of their previous work in a portfolio or more details about their qualifications and experience. 

          If the longevity of your insulation is a key concern for you, discuss with your installer which types of loft insulation will last longer in your home. Not only will they be able to successfully and effectively install your new insulation, but they’ll be able to remove your old insulation (if you have it), and advise you how much insulation and which type is most suitable for your property.

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