How Long Does Ceiling Insulation Last?

The lifetime of your ceiling insulation will firstly depend on the type of insulating material used. The most common materials used for ceiling insulation are glasswool, polyester, cellulose and spray foam. Each of these materials has advantages and disadvantages that affect the insulation's longevity. However, there are other factors that may affect the performance of your insulation, and it may be time to make the climb into your ceiling space to check your insulation status.

Which Material Lasts The Longest?

Glasswool insulation, also known as fiberglass is the most commonly used insulating material and should last the lifetime of your home. Knauf provides a warranty of 50 years on its Earthwool range and Bradford provides a 70-year warranty across a number of ceiling, wall and floor products.

Polyester insulation is available in ceiling insulation batts and is made from recycled plastics. This material is naturally hydrophobic which means it is water repelling, quick drying and unaffected by moisture. Autex provides a product durability warranty of 50 years on its GreenStuf range.

Cellulose insulation is made from a mixture of recycled paper and wood material. Cellulose is blown into the ceiling space during installation and typically lasts around 30 years. Cellulose material degrades faster than glasswool and polyester insulation.

Spray foam is more expensive than most insulating materials and requires a professional installer, which adds to the overall cost. Spray foam is better at sealing air leaks, preventing water leaks and minimising mould growth.

What Factors Can Affect The Life Of My Ceiling Insulation?

It is the millions of tiny air pockets in the insulation material that slow down heat transfer. If these air pockets are compressed or become wet, then the insulation will no longer have optimal performance. It is important to check your ceiling insulation batts for any moisture absorption which may be caused by faulty plumbing or roof leaks. Additionally, check your ceiling insulation batts for signs of mould. Any wet insulation should be removed and replaced immediately, or as soon as the water leak source has been fixed. Your ceiling space may also be home to rodents and insects which nest in the insulation material, this can leave areas uninsulated and exposed. Having open or damaged areas in your ceiling insulation will compromise its effectiveness. It pays to check the condition of your ceiling insulation periodically, and in particular after a severe weather event. If you have just moved into a new home, check your insulation at the earliest. View our installation videos for tips on retrofit DIY ceiling installs.

When Should I Replace My Ceiling Insulation?

You don’t necessarily have to remove what you already have. Check the condition of your ceiling insulation and if it is undamaged, you may be able to simply top up your insulation and enhance the combined R-value. If there is obvious damage to the insulation material it should be replaced altogether. For more advice refer to our ceiling insulation tips page.