A Complete Guide To Insulation Boards

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Insulation boards are the best option for roof insulation, and insulating walls and floors. Some of the obvious benefits of using insulation boards include:

What Are The Benefits Of Insulation Boards?

Insulation boards are rigid boards or sheets made of gypsum or foamed polystyrene , polyiso, or polyurethane. Their closed-cell insulation works primarily to restrict heat loss in any given application.

Before going into the details, let's discuss insulation boards in general:

Different insulation boards also mean choices. Choices can be overwhelming, and that is why we have put together a brief guide on insulation boards for you.

There are several types of insulation boards available in the market today. From foamed insulation boards like PIR or polystyrene to plasterboards - standard, insulated or specialised - all used to protect your home from fire, heat loss or moisture.

How To Cut Insulation Boards?

Insulation boards can be cut to size using a sharp utility knife or a table saw. To cut insulation boards, you need to lay them flat on a surface and measure and mark the surface using a pencil or marker. Ensure that you have protective gear like masks and gloves on while cutting insulation boards.

Where Are Insulation Boards used?

Insulation boards can be used for:

Roof Insulation:

Board insulation can be used to insulate pitched and flat roofs. Insulation boards can be cut to size and used either under or above the roof rafters or between the ceiling joists (though loft insulation roll works better between ceiling joists since they can be easily rolled out). 

PIR insulation boards like Celotex GA or Xtratherm XT/PR and lightweight insulated plasterboards like Knauf XPS laminate work best for roof insulation applications.

Wall Insulation

Foam insulation boards, like PIR or polystyrene insulation, can be used to insulate walls. For stud wall insulation, PIR boards are an excellent choice. Alternatively, you can also use insulated plasterboards like Celotex PL or Knauf XPS thermal laminates for internal walls. Foam insulation boards, like Celotex CW, can be used for cavity wall insulation.   

Floor Insulation: 

Insulation boards like extruded polystyrene and expanded polystyrene are perfect for floor insulation. They have high compressive strength, making them ideal for underfloor insulation as well. At Buy Insulation Online, we also stock underfloor insulation boards or underfloor heating boards from leading brands like Cellecta, Prowarm, and Warmup.

Different Types Of Board Insulation:

Polyisocyanurate Insulation Boards

PIR insulation is the market-leading insulation board, simply because of its unmatched thermal efficiency. The closed-cell nature of PIR boards allows a low thermal conductivity of 0.022 W/mK, which ensures that the heat stays indoors, no matter the application.

PIR or Polyisocyanurate insulation boards are generally about 2.4m long and about 1 2m wide. They are available in different thicknesses ranging from 25mm to 200mm. 

These insulation boards offer high thermal performance per inch thickness. Additionally, they have low-emissivity foil facings that reflect radiant heat. The foil-facings also serve as a moisture barrier that protects these foam boards and their application against moisture ingress.

PIR insulation is dimensionally stable, long-lasting, and durable. Additionally, they are environmentally friendly, with zero ozone depletion potential, and low global warming potential. 

As discussed above, PIR insulation boards are very versatile in application. They are used to insulate walls, cavity walls, roofs, floors, and much more. These insulation boards can be cut to size using a sharp saw. They are secure to place using adhesives or drywall screws. 

At Buy Insulation Online, we stock Celotex PIR insulation boards like Celotex GA, XR and TB at a low cost. We also stock PIR boards from known brands like Xtratherm and Iko.

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Polyurethane Insulation Boards

PUR foam boards or Polyurethane insulation boards are extremely effective at maintaining the internal temperature of a building and can last for the entire life of the building. Besides being durable, polyurethane insulation boards also resist moisture ingress and are fungus-free. 

Moreover, they do not emit any hazardous emissions. And since polyurethane is a non-fibrous material, they do not cause any allergies or asthma.

PUR foam insulation boards feature a dual layer of polyurethane insulating material. The polyurethane layer is arranged between the inner and outer panels.

Additionally, the grooves in polyurethane insulation boards allow for rapid installation and fixation, which greatly improves work efficiency. Another benefit of polyurethane insulation boards is that they are lightweight, making them easy to install and maintain.

Polystyrene Insulation Boards

Depending on their manufacturing process, polystyrene insulation boards can be divided into: 

Extruded polystyrene Insulation Boards:

EPS insulation boards have excellent insulating and shock-absorbing characteristics. The cellular structure of EPS insulation makes it water-resistant and vapor-permeable with a low moisture absorption rate. Although water vapor cannot affect the mechanical properties of EPS, it does attract insects, such as termites.

EPS insulation boards are available in varying densities and thicknesses. A standard expanded polystyrene insulation board is about 2.4m long and 1.2m wide. EPS insulation boards are easy to install and lightweight. This makes them an excellent choice for many applications.

EPS insulation boards are also durable and provide superior thermal insulation. They are cost-effective as well. Their high compressive strength is what makes these EPS boards ideal for floor insulation applications

At Buy Insulation Online, we stock Jablite and Stylite EPS70 insulation boards. They are sold as loose sheets at highly competitive prices.

Extruded polystyrene boards:

XPS insulation boards are a step up from EPS insulation. They are more durable, have a lower K-Value, and are suitable for load-bearing situations. Extruded polystyrene boards are mostly used for floor and underfloor insulation applications. 

Its unique closed-cell structure allows it to exhibit high compressive strength while maintaining low thermal conductivity. Its lightweight construction, low cost, and ease of installation make it ideal for insulating any surface. We at Buy Insulation Online stock XPS insulation boards from top brands like Prowarm and Polyfoam.

XPS and EPS insulation boards are a great choice for energy-efficient buildings. Both materials offer high thermal efficiency and compatibility. Moreover, their closed-cell structure prevents water penetration and offers long-term strength.

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Plasterboards:

Plasterboards or drywall, are made of calcium sulfate dihydrate or more commonly called gypsum. Plasterboards gained popularity over recent years due to their ease of use. They are a faster, better alternative to the traditional lath and plaster. 

Plasterboards can be used for drylining applications. There are different types of plasterboards:

Insulated Plasterboards:

In these cases, an insulating material like PIR or polystyrene - expanded polystyrene or extruded polystyrene, is backed on standard plasterboard. They are generally about 2.4m in length and about 1.2m wide. 

Insulated plasterboards combine insulation and drylining into one lightweight, easy-to-use insulation board. They save space and have good thermal efficiency. These insulation boards can be used to insulate roofs and walls. 

Depending on the type of insulating material, insulated plasterboards can be further classified into:

PIR insulated plasterboard - As the name indicates, the insulating material used here is PIR foam. PIR board of varying thickness is backed on a 12.5mm standard plasterboard. At Buy Insulation Online, we stock Xtratherm and Celotex insulated plasterboards.

XPS insulated plasterboard - Here, the insulation comes from the extruded polystyrene, which is backed on a 9.5mm plasterboard. At Buy Insulation Online, we stock Knauf XPS laminate plus, for superior insulation.

EPS insulated Plasterboard- Commonly called thermal laminates, EPS insulated plasterboards contain EPS boards of varying thicknesses backed on a 9.5mm standard plasterboard. At Buy Insulation Online. we stock Knauf EPS thermal laminates at a low cost.

Specialist Insulation Boards:

These plasterboards are made specially made with high-quality gypsum for applications that require high moisture resistance, fire resistance, sound insulation etc. 

At Buy insulation Online, we stock the following specialist insulation plasterboards:

Knauf Moisture panel: These moisture-resistant plasterboards can be used to insulate bathrooms, kitchens and other applications where superior moisture resistance is required.

Knauf vapour Panel: These foil-backed plasterboards give excellent vapour resistance. They are ideal for use on the underside of a roof, loft conversions, insulating walls or areas that need high vapour resistance.

Knauf sound shield plus and Knauf sound panels: These plasterboards are made with high-density gypsum and are perfect for applications that require superior sound resistance. If you want to block your noisy neighbors out, but have space constraints, then acoustic plasterboards are the way to go.

Knauf Fire panels: Knauf fire panels are specialist plasterboards by Knauf Insulation give superior fire resistance for 0.5 to 4 hours, depending upon their thickness. They are used in applications that need greater fire insulation.

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Underfloor Insulation Boards:

Underfloor heating and underfloor insulation is gaining popularity in recent years, which is why we have sourced some underfloor insulation boards for electric and water underfloor heating applications just for you. 

At Buy Insulation Online, we stock Prowam Lo-Flo screed boards, chipboards, dual overlay systems, and underfloor heating panels from some of the leading brands in this niche, like Prowarm, Cellecta and Warmup.

These underfloor insulation boards ensure that the heat is directed upwards, that is, towards the floor and is not lost through the subfloor. Pre-routed chipboards secure the pipes of wet underfloor heating easily and ensure that the heat is not lost.

Duct Insulation Boards: 

Rectangular and square shared ductwork can be insulated easily using duct insulation boards. These specialized insulation boards are made of mineral wool, PIR or phenolic foam and give superior insulation to ducts. 

At Buy Insulation Online, we stock duct insulation boards from the leading brand, Rockwool. Additionally, for improved fire insulation to ductwork applications, we also supply Rockwool FirePro DuctRock which can be used for improved fire resistance in smoke and ventilation ductwork.

In Conclusion:

Insulation boards are rigid, closed-cell structures that give better insulation compared to traditional wool insulation. There can be used to insulate the floor, underfloor, roof etc, and almost always help achieve your target U-values. They save energy and improve your EPC ratings whilst making your home energy efficient.

If you are unsure about the right insulation board for your application, you can either drop a message on our Facebook group or call or us. We will be happy to assist you.

To buy plasterboards or insulation boards online, visit Buy Insulation Online. Along with insulation boards, we also supply batt insulation, insulation on a roll and more. We supply technical insulation products like ductwrap, valve insulation jackets, pipe lagging, trace heating cables, condensate pipe insulation and so on. With every order, we plant a tree for free, and also save five trees in the Amazon! 

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There&#;s nothing like the shock of a cold snap (or a three-figure utility bill) to put loft insulation at the forefront of your mind. So why wait until winter?

From natural sheep&#;s wool to affordable fibreglass, insulating your attic has its benefits all year round. It keeps your house cool in the summer while toasty through the brisk winter.

If the expense and hassle of finding a reputable tradesperson to do the job for you are putting you off, here&#;s some good news. Is your loft easy to access and has no dampness or condensation problems? Then it is something you can insulate yourself, even if you struggle to hang up a picture!

So, which type of insulation is easiest to install, and how thick should loft insulation be? Our guide to buying loft insulation can answer those questions and more. When it comes to installing, use our loft insulation installation guide.

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How does loft insulation work?

Understanding how loft insulation works is key to knowing which option is best for you. From windows, doors and walls, heat can escape from your home in many different places. Having said that, a big chunk of this precious energy (around 25% in an uninsulated home) gently wafts out through the roof.

Loft insulation stops rising heat in its tracks. This turns your attic into a shield between your warm home and the cold outside world.

From sheep&#;s wool to glass and even rigid boards, loft insulation comes in many materials, but they all work in similar ways.

How? By trapping heat in air pockets and stopping it from escaping into the atmosphere.

It works all year round, too. In summer, insulation stops warm air from coming in. This helps keep your home feeling cool and comfortable.

Laying rolls of insulation doesn&#;t mean you have to stop using your loft for storage, either. Just don&#;t compress the blanket of insulation, and remember to leave an air gap. This allows moisture to escape, and you can put down floorboards over the top.

What are the benefits of loft insulation?

If you thought your loft was only handy for storing Christmas decorations. that&#;s not all. Here&#;s why insulating the attic is a clever trick that&#;s well worth your time and effort.

Suitable insulation throughout the seasons

Your home will feel warmer in the winter and cooler in the summer.

Fewer condensation issues

A well-insulated loft means you won&#;t have as many problems with condensation.

You&#;ll notice a difference

Homes lose a quarter of heat from the roof. So, if your home&#;s currently uninsulated, you&#;ll notice a huge benefit straight away.

Can last for decades when installed correctly

Done properly, loft insulation can be effective for up to 40 years (and up to 50 years if you use sheep&#;s wool).

Efficient for your budget

It&#;s so cost-effective that it&#;ll easily pay for itself many times over. You could save up to £215 on your energy bills each year, according to the Energy Savings Trust.

Eco-friendly

You&#;ll be doing your bit for the environment. Currently, a third of all carbon emissions come from heating draughty homes.

Minimises external noise

Outside noise will be greatly reduced &#; good news if your home is under a flight path or next to a busy road.

Will help boost your EPC

Insulation can help boost your home&#;s Energy Performance Certificate rating. A huge plus if you were thinking of selling in the future.

Want to insulate the roof itself? You can find out more about insulating a roof via our dedicated guide.

Insulating joists vs. insulating rafters

A pitched (sloping) roof has two options when it comes to insulation. You must decide whether to insulate the joists (the floor of the loft) or the rafters (the loft walls). How you choose depends on whether you want to create a cold or warm loft space.

If you only use your loft for general storage

Perhaps you only put your holiday items up there. Maybe some suitcases. In this case, creating a cold loft is normally your best bet. It&#;s less expensive, less fiddly and a relatively easy job to do yourself.

For a cold loft, you only need to insulate the space directly above the ceiling of the top story of your home. Luckily, there is an easy way to do this. Simply lay a blanket of insulation (known as loft rolls) between and over the joists of the attic. After that, you can choose whether you want to lay floorboards over the top or not.

If you plan to store some heat-sensitive items or want to use the attic for your hobbies

Is your attic your space for &#;you&#; time? Somewhere you can put your items safely without worrying about them? In this case, you&#;ll need to create a warm loft. Warm lofts can keep the heat in the winter and stay cool in the summer,

Now, to achieve this, you will need insulation just under the roof in the rafters. This will need a little more technical know-how. Having said that, it can be worthwhile as it&#;s an effective way of keeping the heat in your home.

What type of loft insulation do I need?

Your options for loft insulation vary, depending on whether you plan to insulate the joists or the rafters.

Insulating the joists

For a cold roof, you can take your pick of loft rolls. This includes:

• Mineral wool
• Sheep&#;s wool
• Glass wool

There is even specialist acoustic wool, great for blocking out outside noise.

If you already have insulation in place, you can choose to use loose fill products to top it up. Rather than laying down a blanket of insulation, loose fill comes in bags. You can open and pour this into any space that looks a bit sparse. It&#;s a really easy job that requires no DIY skill whatsoever.

If your loft is damp, slab insulation is a great choice. It&#;s easy to fit, water-repellent and breathable. So you won&#;t get rot or mould.

Planning to use your loft for storage? Going for rigid insulation boards could save you time and effort, as you get boards and insulation in one. It is more expensive than loft rolls. However, they offer the same heat-retaining capabilities but are half as thick.

For example, you buy an insulation board with a thickness of 135mm. This has the same level of insulation as 270mm of mineral wool.

Whatever kind of joist insulation you go for, remember that the loft space above will feel very chilly in the winter and hot in the summer. This is not great if you want to store anything valuable.

You&#;ll also need to remember to insulate your pipes and water tank before any cold snaps as they could be liable to freeze.

Insulating the rafters

Your options for insulating the rafters are a little more limited. That&#;s because the products used to create warm lofts tend to be denser and more rigid than those used for insulating joists. Then there&#;s the little problem of how to get the insulation to stay put without falling.

Rather than loft rolls, you can buy mineral or glass wool insulation in batts. To hold these in place, you use battens of wood attached to the rafters. Alternatively, you can use normal insulation held in place by netting.

Insulation boards are also a great option for warm lofts. You can cut them to the right size to fit snugly between the rafters. Whereas you can put insulated plasterboard over the rafters themselves. This makes sure your insulation meets the required depth.

What depth should loft insulation be?

The government recommends a depth of at least 270mm. Having said that, many new properties are exceeding this going up to a depth of 300mm.

If you choose to go for 300mm (or more) you will lose a little space, but if your home feels cold it could be worth it.

Did you buy a house with the insulation already in place? Unless the property is a new build, it&#;s worth checking how deep your insulation is because it may be time for a top-up. The recommended depth was 200mm in . So anything built before then likely won&#;t meet today&#;s insulation targets.

What materials should I use for my loft insulation?

Loft rolls come in a range of materials, and the type you go for will depend on how you&#;ll be using it. Don&#;t know your sheep&#;s wool from your mineral? Here&#;s an explanation of each.

Mineral wool

Mineral wool comes in rolls, like a blanket. You install them by laying them down between the joists and then placing them on top to take them up to the recommended depth.

You can also use mineral wool to insulate rafters by cutting and fitting them to size. To stop them from falling, use insulation fixings.

One of the best reasons for mineral wool insulation is that it&#;s lightweight and inexpensive. Manufacturers make the mineral wool from rock which they heat until it melts. Then it&#;s spun and bound together with resin and oil.

Sheep&#;s wool

Wrap up your loft with soft, natural sheep&#;s wool. Sheep&#;s wool insulation is safe to touch and won&#;t irritate your skin. So you can handle it without wearing protective clothing.

You can use it for insulating joists and rafters. It&#;s also great for absorbing moisture and preventing mould and rot.

Glass wool

The most popular type of loft insulation in the UK, glass wool (also called fibreglass) is one of the cheapest.

Manufacturers make fibreglass insulation by melting glass and sand together. Then spun to form fibres which are bound together with resin. The resulting blanket looks like sheep&#;s wool and is just as flexible.

Here is a summary of the pros and cons of each type of loft insulation.

Type of insulationProsCons Mineral wool&#;Excellent thermal and acoustic insulation
&#;Easy to install
&#;Offers great fire resistance&#;Will compress if you put weight on it
&#;Can irritate bare skin Sheep's wool&#;Safe to touch
&#;Easy to install
&#;Pleasant to handle
&#;Breathable (can prevent dampness from damaging wooden timbers)&#;Less cost-effective
&#;Will need more to be installed to get the same thermal values as usual
&#;Not as good an insulation as other wool roll alternatives Glass wool&#;Fire resistant
&#;Insect repellent
&#;Eco-friendly (mostly made from recycled glass&#;Most glass wool irritates the skin (protective clothing must be worn when handled)
&#;Becomes less effective when wet
&#;Not suited to damp areas

What else could I use to insulate my loft?

While laying down loft roll insulation is a popular choice, it&#;s not the only option. In fact, some of the alternatives might suit you better.

Insulation boards

Also known as rigid boards, you can use these to insulate both joists and rafters. They&#;re a great choice if your loft is large.

One drawback is they are often more expensive than rolls. Having said that, they offer good thermal values at half the thickness. Also, you can easily store items directly on top of them. If you need to cut them to size, you can use a saw so that they fit snugly between joists or rafters. This also lets you be able to drill holes around light fittings.

Insulation slab

Slab insulation products are becoming increasingly popular. They&#;re easy to install, with most products friction-fitting between joists or rafters.

As well as keeping your home toasty, they&#;re one of the most fire-resistant choices. There are some slabs made from stone, but they&#;re still easy to cut and fit your space.

Foil insulation

Foil insulation comes into its own when insulating the rafters. Also known as multifoils, it consists of layers of reflective and insulating materials. This allows heat to reflect into the room.

It&#;s easy to install as you simply staple the foil to the rafters and tape over any joins.

Acoustic insulation

Perhaps you want to protect your ears from outside noise. Maybe stop neighbours from complaining if you&#;ve decided to take up the drums. Acoustic insulation is a great idea for many different reasons.

Some acoustic insulation (as seen in the image below) stops noise transfer from room to room. That means it will stop footsteps in the loft travelling to the room below.

From acoustic wool to slabs, sound insulation comes in many forms. Sheep&#;s wool is a popular choice if noise is an issue. It offers unparalleled warmth alongside effective sound reduction.

Still in the early planning stage? Our dedicated guide to insulating a loft can help you define your planning process and understand what the best loft insulation is for your circumstances.

The benefits of loft insulation

Loft insulation offers several benefits, including improved energy efficiency by reducing heat loss through the roof, leading to lower heating bills. It also helps maintain a more consistent and comfortable indoor temperature throughout the year by reducing drafts and cold spots.

What&#;s more, loft insulation can contribute to environmental sustainability by lowering carbon emissions associated with heating, mitigating the impact on climate change.

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