How Long Does Loft Insulation Last?

Tuesday 27th February 2024

Joanna Grimbley-Smith

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Insulation roll in an attic CONTENTS



Over time, insulation can settle and lose its thermal resistance, leading to increased heating costs and a less comfortable living environment. Knowing when to have it replaced is crucial to maintaining your home's energy efficiency.

Here at ICE Thermal, our experienced engineers can replace your old loft insulation with our loft insulation installation services. We operate nationwide and are available 365 days a year, including bank holidays. 

Read on to learn more about how long insulation lasts and when you should replace it. 

The importance of loft insulation

Loft insulation is a critical component in maintaining the energy efficiency and comfort of your home. 25% of heat is lost from a property via the roof so properly installed loft insulation can significantly reduce heating and cooling costs, making it an essential investment for homeowners, landlords, and tenants alike.

You can learn more about the benefits of thermal insulation in this blog

How long does loft insulation last?

The lifespan of loft insulation depends on several factors including the type of material used and how well it is installed. Generally speaking, most loft insulation is designed to last for around 40 years. However, this duration can be affected by external conditions such as moisture ingress or pest infestations which could compromise its effectiveness over time.

To maximise the life expectancy and performance of your loft insulation, professional installation is recommended. Attempting DIY installation without proper knowledge or tools can lead to poor placement that diminishes its insulative properties.

Regular checks on your insulation is crucial to make sure it is performing optimally, too. Recognising when your insulation has settled or degraded allows you to take timely action - whether that means adding more layers or replacing old materials entirely.

How long do different insulation materials last?

Fibreglass insulation

Fibreglass is a common choice for loft insulation due to its cost-effectiveness and ease of installation. Although loft insulation rolls can last for 80 to 100 years, fibreglass can compress over time, diminishing its capacity to encase air and stop heat escaping from your home. 

To maintain optimal performance, it is advisable to check fibreglass insulation every few years for signs of compression, damage, and dampness which can affect how well it insulates a property. Replacing or topping up compressed areas helps restore the material's thermal resistance.

Cellulose insulation

Made from recycled paper products, cellulose insulation is an eco-friendly option that boasts superior thermal properties. It typically has a shorter lifespan than fibreglass, and lasts for around 15 to 20 years under ideal conditions. However, like fibreglass, its longevity can be compromised by improper installation or environmental factors, such as dampness.

Regular inspections are crucial for cellulose insulation, too; they let you spot potential issues before they escalate into bigger problems like mould growth or reduced efficiency.

Spray foam insulation

When properly installed by professionals, spray foam can last more than 50 years without significant degradation in performance. This type of insulation adheres well to surfaces, creating a tight seal that significantly improves energy efficiency.

The key with spray foam is ensuring it is professionally applied. Incorrect application may lead not only to reduced lifespan but also potential health risks from off-gassing chemicals during installation.

Rigid foam board insulation

Loft insulation boards offer robust thermal resistance with lifespans extending upwards of 50 years when protected from UV rays and mechanical damage. They are often used in conjunction with other types of loft insulation for enhanced heat retention.

Careful handling during installation ensures these boards remain effective over their lengthy service life. Cracks, for example, can compromise their insulating properties. Regular checks help identify any maintenance that is needed early on.

The signs you need to replace your insulation

Although adding new layers of insulation on top of old ones can restore the energy efficiency of your property, there are times when the existing material needs complete replacement.

Increased energy bills

If you notice a sudden spike in your heating or cooling bills without a significant change in utility rates or usage patterns, it could indicate that your loft insulation is no longer performing effectively. 

Dampness or water damage

Insulation that has been exposed to water from leaks can clump together, losing its effectiveness. This not only reduces the insulative properties but also poses risks for mould growth which can affect air quality and put your health at risk. If patches of dampness or signs of water damage are visible on the ceiling below the loft, it is likely time for an inspection.

Pest infestations

Rodents and insects often find their way into lofts seeking warmth during colder months. Nesting and physical harm by these unwelcome visitors hampers the effectiveness of insulation. Droppings left behind by pests can contaminate the material, too.

Finding evidence such as droppings, gnaw marks, or even visual confirmation of these uninvited guests means urgent action is needed. It is recommended you first contact pest control professionals to eradicate the pest problem, and then look into whether insulation replacement is required. 

The material has aged beyond its life expectancy

Even if your insulation does not get damaged, all materials will degrade to a point where they are no longer able to offer the required levels of protection against heat loss or gain.

If you are unsure about the state of your existing insulation, it is wise to get in touch with thermal insulation installers. They will assess the condition of your insulation and can advise on whether replacement is required. 

How to replace your insulation

It is recommended you always bring in professionals for insulation installation. Firstly, experts possess the necessary knowledge about different types of insulation materials suitable for various homes. They can assess your specific needs based on your house's structure and recommend the best solution accordingly.

Thermal insulation engineers can also ensure that the insulation covers all areas effectively without leaving gaps or spaces which could lead to heat loss. This will prevent common issues such as dampness or mould growth caused by incorrect fitting, too.

Get in touch

To book your loft insulation installation, just contact our team on 020 3376 4802 or send an email to [email protected]. Our friendly team will be happy to schedule your free site survey and provide you with a no-obligation quote. 


Melissa Harrison

Melissa Harrison

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