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What Is The Best Roof Insulation In The UK?


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Whether you are building from scratch, remodelling, or adding on, home insulation should be one of your top priorities. If you don’t pay close attention to this part, your home will not only feel less comfortable to live in, but your energy bills will also go up. Besides that, the Building Regulations say that certain things must be done when starting from scratch.

In this article, we look at the different types of roof insulation you can choose from and talk about the pros, cons, and costs of each. Moreover, you can apply to the GBIS flat roof insulation scheme and check if you are fulfilling the application criteria.

Things You Need to Know Before Deciding the Type of Roof Insulation

Before you choose the best things for your home, you should think about a lot of things. Before you decide what to do, ask yourself these questions. The answers will help you find the best option.

  • Which kind of roof are you insulating? Lofts, houses, sheds, and other things.
  • How much cash do you have? Are you ready to buy some insulation?
  • What kind of roof do you have? How deep are the rafters?
  • Start from scratch or fix up what you already have?

Types of Roof Insulation

There are various types of roof insulation on the basis of the material selection. Let’s put some light on each type and discuss the unique advantages of each.

Loose fill insulation

Stone wool, cellulose, fibreglass, and even cork bits can be used to make free fill insulation. Products with a lot of recycled materials are a great choice for the environment.

Since loose fill insulation is often blown into place, it can be used in hard-to-reach roof places. To learn more about loose-fill cellulose insulation, read our guide.

Rigid Insulation Boards

A lot of people use foam plastic insulation, which is also called plastic foam, to insulate different parts of their homes, like the roof.

Foam plastic refers to insulation materials made from chemicals that come from oil. Different types of insulation are made with these oils. Most of them are shaped into stiff slabs.

The best way to insulate your roof will depend on how it’s built, but stiff boards are usually used on the gable walls, party walls, loft room chimneys, and between the rafters.

Spray Insulation for Roof

Before you put spray foam insulation on the roof, you should spray polyurethane or latex on the bottom of the roof deck, the slates, and the tiles. In addition to keeping the area warm, this will fill in any holes and keep water out.

But keep in mind that spray foam insulation should only be used on roofs that are well taken care of. It’s possible for some companies to offer to fix your roof by adding foam insulation directly to the bottom of it, without first fixing the problem.

Sheet Roof Insulation

Sheet insulation for the slope side of the roof comes in the form of a hard board made of natural or man-made materials. This type of insulation not only keeps out fire and water, but it also has a nice finish that makes it look good.

Because it is strong, the insulation material is easy to work with. Sheet insulation is more expensive than other types, but it is well worth the extra money because it works better.

Mineral Wool Insulation for Roof

Stone, volcanic rocks, or recycled glass are the main things that are used to make mineral wool insulation. Salt, lime, and sand are then added. After being melted, the ingredients are spun into strands, which is similar to how fibreglass insulation is made. You can buy it in batts and rolls.

It costs a little more than fibreglass insulation, but it is easier to work with, cut, and place, and it blocks out noise better.

But, just like with fibreglass insulation, it’s best to wear safety gear like gloves, goggles, and a face mask because the fibres can still hurt skin. Besides that, it doesn’t break down naturally.

Blown Fibre insulation

It’s easy to install if you hire a professional; all you have to do is blow the insulation between the frames. Blowing fibre insulation is easier to handle and lighter than other types, so it takes less time to put up.

One bad thing about this type of loft insulation is that it might cost more than other types. It’s also not the best choice for lofts that get cold in the winter.


If you want to use something other than wool or fibreglass for this kind of insulation, you can. Fibreglass insulation is sometimes sold in rolls that are easy to cut to the size you need, but they can be awkward to move around. As long as there is a roofing layer, they are usually put in between the rafters.

Fibreglass insulation is made of glass fibres, which are made by quickly spinning hot glass into threads and then binding those threads together. The air gaps in the glass threads stop heat from escaping.

Blanket insulation

It’s funny that blanket insulation is the most common type of insulation for lofts. It comes in rolls made of rock, natural fibre, glass, felt, or even sheep’s wool with foam on the back. Putting insulation on a roof is usually pretty easy, but it can be hard to do in small spaces.

Some materials are bad for the skin, so you need to wear safety gear when working with them, even if the work is easy and doesn’t need the help of professionals.

Natural Insulation for Roof - Sheep wool, Wood grain, Cellulose, Wool, Flax and Cotton

You can get eco insulation in rolls, thick boards, and free fill. A lot of the time, wood grain and cork are sold in board form.

Wood fibre insulation lasts a lot longer than cork, and companies like Pavatex, Gutex, and Steico make waterproof types that can be used for roof insulation.

Cellulose is the most common type of loose natural insulation. However, cotton, flax, and sheep’s wool are sometimes used in layers of flexible natural insulation.

Polyurethane Foam

Spray foam roofing has the best protection for the building because it blocks heat, air and water and has the highest R-value per inch. Polyurethane foam keeps heat in during the winter and keeps it out during the summer, which may help building owners save money on their energy costs. Most spray foam roofs are expected to last about 20 years after they are installed.

Polyester & Glass Fibre Insulation

Polyester insulation not only keeps hot air out of your home in the summer and warm air in during the winter, but it also blocks noise very well. Polyester insulation will make your home quieter and calmer because it will let less outside noise in.

Given that it doesn’t provide a fire danger, fibreglass is a popular material for housing insulation. Thermal insulation, which may lower domestic energy expenses by up to 40%, is said to preserve 12 times as much energy as is wasted during manufacture when it comes to fibreglass and its substitutes.

Glasswool is non-combustible, so it will not catch fire. Polyester is only fire proof. Furthermore, glasswool is bio-soluble, which means that people or animals can eat it and it will break down. This gives families with kids or pets an extra measure of safety.

The Cheapest of Roof Insulation Material

Most of the time, rolls of fibreglass insulation or free fill insulation are the least expensive type of roof insulation. Spray foams and natural insulation are the most expensive.  

When figuring out how much roof insulation will cost, it’s important to think about how much money you will save by doing the work. Keep in mind that a house’s roof loses about 25% of its heat.

Factors Affecting the Roof Insulation Installation

  • The thickness of the substance 
  • The type of insulation it has
  • What kind of roof the building has
  • The size of the roof and how easy it is to get to the top


Finally, if you want to find the best roof insulation for your home in the UK, you need to carefully think about a number of factors. Like any other insulation, free fill, hard insulation boards, spray, sheet, mineral wool, structural insulated panels, blown fibre, fibreglass, blanket, and natural insulation all have their own pros and cons. 

You should weigh the impact on the climate, the cost, and the ease of fitting against the needs of your roof. People can also get help with insulation from the government through programmes like the GBIS flat roof insulation scheme. Spending money on good roof insulation will not only make you more comfortable over time, but it will also save you money and energy.

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