What Is PIR Insulation? Everything You Need to Know

Polyisocyanurate - commonly known as PIR insulation - is a synthetic polymer derived from polyurethane, one of the most highly effective and popular materials used for insulation in homes and properties. 

With its incredibly high R-value, flame resistance, and long-term durability, PIR insulation is a popular option for various house insulation projects. But what is PIR insulation? This ultimate guide by GreenMatch UK will break down everything you need to know about PIR insulation, its properties, pros, cons, costs and applications.

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You may be wondering; what does PIR insulation stand for? PIR insulation stands for polyisocyanurate, a highly effective thermal insulation material. This is a material that has the same components as PUR insulation (polyurethane) but with more improved properties such as high flame and smoke resistance, durability and thermal efficiency. 

PIR insulation is also one of the most thermally efficient on the market today, exhibiting an impressive R-value range of 3.6 - 4.5 m²K/W and a very low thermal conductivity. PIR insulation boards can cost around £5 – £15 per m2 of material and are normally found in the form of rigid insulation boards and sheets. 

While slightly more expensive than some other insulation materials, PIR insulation boards are certainly very effective, durable and long-term beneficial solutions for home insulation.

PIR insulation is most often used as insulation for walls (internal and external), concrete floors, and insulation for loft spaces, most often via roof rafters. PIR boards can also be used as insulation on roof solutions for flat roof properties but must be covered properly to avoid sunlight and moisture damage.

Due to the rigid nature of PIR boards, they are not so suitable for insulating awkward angles, curves and hard-to-access spaces, but are highly ideal for flat unobstructed spaces. 

During the installation process, these rigid insulation boards can be cut into desired shapes and lengths, and attached directly to the surface being insulated alongside a vapour barrier. This can be followed with plasterwork or covering for a clean seamless finish.

Polyisocyanurate (PIR) based insulation materials are found in the form of rigid panels, sheets and boards. All three of these forms are very similar to each other, and usually only differ in thickness, ranging from about 20mm to 200mm. 

Standard PIR insulation boards are found to be around 2.4m long and about 1.2m wide. Most of the panels, sheets and boards on the market will also come with a pre-bonded low-emissivity foil layer to increase thermal insulation and double as a vapour barrier. 

Even though PIR insulation is inherently water resistant, it is certainly not immune to water damage. As a rule of thumb, all insulation can accrue serious damage if there is prolonged exposure to moisture. 

To avoid such situations from taking place, it’s important to work with a professional installer who can also address existing issues, and make sure your insulation is installed properly. Creating healthy ventilation can also help keep insulation dry in the event of a moisture breach.

PIR insulation is extremely robust, boasting a lifespan of up to 50 years when taken good care of. This gives it one of the longest lifespans of insulation materials on the market.

As a general rule, assessing the condition of your home insulation every 15 - 20 years is a great way to preemptively avoid serious issues from taking place, but with proper care and checks, you can enjoy up to 5 decades of home comfort and uninterrupted peace.

PIR insulation is without a doubt a highly effective home insulation option, but like any insulation material, there are a series of pros and cons worth considering. Let’s first begin with the pros:

With all of its positives, it’s also worth having a look at some of the shortcomings of PIR insulation to get the best picture. Here are some key points to remember:

With all these pros and cons in mind, it’s safe to say that there's plenty to applaud about PIR insulation, but also to be mindful of. The best approach to choosing home insulation is to consult with a professional installer and home insulation companies to find your best fit.

Unfortunately, not everyone has endless weeks at hand to spend on researching and vetting installers, often also missing out on key bargains. Luckily, GreenMatch UK can help out.

Through our services, you can receive up to 3 free home-tailored quotes directly from our network of pre-vetted installers. The best part? There are no charges or obligations in place. Simply fill out our 30-second form and let the bargains come to you. Click the button below to begin!