Thermal Insulation

When it comes to reducing heat transfer and improving the overall thermal envelope of a property, thermal insulation is a must. Not only is thermal insulation material energy-efficient, but it can also bring a host of additional properties such as fire resistance, water resistance and durability. At Materials Market, you can choose from a range of insulation forms – insulation boards, insulation rolls, insulation slabs and insulation foil – from industry-leading brands like Kingspan, EcoTherm, and Rockwool.

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What is Thermal Insulation?


Heat flow is inevitable when objects of differing temperature come into thermal contact. Thermal insulation is the process or method by which we aim to prevent heat transfer between these objects. In other words, insulation acts as a barrier between the air inside a property and the air outside. Its job is to reflect thermal radiation, which, as a result, regulates the temperature and thus, thermal comfort of a property. 

The materials used to create thermal insulation are far and wide, with the most popular insulation materials on the market including rock mineral wool, fibreglass, and polyisocyanurate (PIR). 

No matter the material, the main commonality between all thermal insulation materials is their low thermal conductivity; the lower the conductivity the better. 

Insulating materials may have a wide range of applications and be constructed from equally diverse materials, but they all provide the same basic advantage: lower energy expenditure which results in increased efficiency and lower energy bills. 

Best Materials for Thermal Insulation


When producing thermal insulation, insulation manufacturers utilise specially engineered methods that trap chemicals and still air so that the material cannot effectively transfer heat. 

With the number of thermal insulating products on the market (and the many different properties that come with them), it can be difficult to choose the right material for your project.

Let's explore a few types below: 

Rockwool Insulation Slabs

Rockwool is a 3-in-1 acoustic, thermal and fire insulation suitable for a range of general building projects as well as specialist specifications such as commercial, leisure, and industrial buildings.

Despite their many benefits, these resin-bonded rock mineral wool slabs are unrivalled in their soundproofing abilities. Above all else, their primary purpose is to quell unwanted noise and keep voice leaks to a minimum within a building.

Another quality they excel in is their ability to reduce fire spread; with an A1 (non-combustible) rating on the Euroclass scale, you can rest assured that these premium-quality semi-rigid slabs are optimising the fire protection of your build - prevention is better than cure, after all.

With a thermal conductivity of 0.035 W/mK, you can rest easy knowing that it's not just your project's fire resistance they are working; they are protecting its thermal envelope in tandem.

One of the most popular manufacturers we stock rock mineral insulation from is Rockwool.

PIR Thermal Insulation Boards

PIR (a widely-used shorthand term for 'polyisocyanurate') insulation gives contractors and homeowners the best combination of affordability, availability and thermal performance in one robust material.

PIR is one of the most effective heat-reduction insulation boards on the market with an impressively low thermal conductivity of 0.022 W/mK.

PIR, along with its thermal efficiency, marries a few simple properties that make for an overall excellent insulation choice; it has a closed-cell structure (and is water-resistant thanks to this), and despite its rigidity is extremely lightweight, making it easy to handle.

To summarise, PIR insulation is a tough, durable, lightweight insulating board comprising two high-performance aluminium facings sandwiched between a rigid PIR insulation core.

Celotex
is one of the most popular PIR insulation board manufacturers.

Fibreglass Thermal Insulation Rolls

Fibreglass insulation, also known as glass wool insulation (or glass fibre insulation), is as the name would suggest, made up of recycled glass fibres. Layers and layers of glass mesh are bonded together; the resulting product of which features thousands of small pockets of air that inhibit warm air from escaping.

As glass is resistant to heat, it's no wonder that fibreglass insulation makes a good insulation material choice for those seeking heat and fire resistance in one robust material. Fibreglass insulation rolls have thermal conductivity between 0.032 W/mK and 0.044 W/mK depending on the product.

Fibreglass wool insulation comes in rolls and slabs or batts. Fibreglass batts – which can also be referred to as slabs – are large, compact insulation pieces that are designed to fit between joists, rafters, and studs. Fibreglass insulation roll contains much more material and can be simply rolled out into joists and other spaces, such as pitched roofs at ceiling level.

We recommend Knauf Insulation rolls for people who want to protect their lofts, crawl spaces, and open walls.

Foil Insulation

Multifoil insulation, otherwise known as foil insulation, is made up of several layers (as hinted by the 'multi' in its name) of sheets and foils. 

Multifoil insulation is engineered to target radiation, conduction, and convection. The multi-foil's reflective layers function as an airtight barrier, helping to minimise condensation. Multi-foil also works to control the amount of solar radiation that enters a property; helping to solve the dilemma of temperature balance throughout the seasons and optimise energy efficiency. 

Foil insulation is most commonly used between rafters and timber studs in roof spaces, but some products can also be effective when applied to floors, walls, or cellars.

Frequently Asked Thermal Insulation Questions

What Is Thermal Conductivity?

The term thermal conductivity refers to the degree to which a material conducts heat. It is measured in watts per meter-Kelvin (W/mK). The higher the thermal conductivity of a material, the worse it performs as an insulator.

PIR insulation has one of the lowest thermal conductivity values on the market. Each PIR board has a thermal value of 0.022 W/mK.

What Is the Best Thermal Insulation For Floors?

PIR insulation is one of the best thermal insulation choices for under laminate flooring. PIR boards are rigid, lightweight, and resistant to water. They also have high compressive strength, which means that they will not become misshapen or less effective over time. 

As well as being an effective thermal insulator, PIR is also easy to cut to size with a simple utility knife - no complicated industry tools necessary. 

What Is the Best Thermal Insulation For Walls?

Walls are one of a property's main heat-loss culprits with approximately 35% of heat escaping through uninsulated walls. It is for this reason that walls are usually the first places we target when insulating a property with the aim of improving its thermal resistance.

On top of comfort and temperature regulation, insulation can be used as a measure to reduce heating bills and CO2 emissions.

Whilst most insulation boards are good thermal insulators, the type of material you choose to insulate your walls will depend on a number of other factors.

For example, if acoustic insulation is your main concern when insulating internal walls, Rockwool RWA45 acoustic slabs.  Whereas people who are after a reliable thermal solution for cavity wall insulation might choose PIR Insulation or Phenolic Insulation, for their excellent thermal properties.

How to Install Thermal Insulation?

There is no one size fits all answer to this question. At Materials Market, we stock thermal insulation from many industry-leading brands that manufacture boards, rolls and slabs. Whether you need insulation installed in internal walls, cavity walls, floors, flat roofs, pitched roofs, or a garage we have the right materials for you to insulate your project.

The installation method depends on where you are going to install the insulation, and what form of insulation you are installing.

For those, looking to install Celotex, we have a handy guide on installation here. Always consult a professional before undertaking the installation of the insulation yourself.