What Type of Insulation Should I Use?

To maintain a warm, energy efficient house, insulation is essential and a good source of insulation will also help to keep a building from overheating in the summer. Without insulation any heat that you pump into your home via a fire or gas heating system will quickly escape leading to high energy bills. You might be surprised to know that on average you will lose 25% of heat through the roof of your home, 35% through uninsulated walls and gaps around windows and a further 10% through the floor.

The addition of insulation can decrease these percentages dramatically and will also stop any damage occurring to your house as a result of mould or rot. Installing insulation into outbuildings is also of great benefit, and will not only prevent any damage occurring to the outbuilding which could lead to infestation from rodents or insects but it will also keep whatever you’re storing in there in good condition and perhaps more importantly provide a usable space for you right through the winter months rather than just in summer.

It’s important to look at what U-Value the type of insulation that you use provides. You can find out all about U-Values here but put simply, the lower the U Value, the better. It’s also advised to leave a ventilated gap between roof tiles and the insulation that you apply so that moisture can vent away.

There are a number of different types of insulation available and many can be used for roofs, floors and walls. This article will run through the differences between the different types and what they are best used for.

Insulation Boards

Insulation boards have one of the best u-values out of all the insulation options, with leading brand Kingspan having a U-value of just 0.022.
Coming in large boards, that can be easily cut to size using a handsaw, the boards can be pushed into place and are ideal for floors, ceilings and walls. They’re a wonderful choice for insulating a garden building or conservatory roof but can be more cumbersome if you are trying to insulate a larger area such as an attic, although, because of their wonderfully low u-value they are still often used for bigger projects.

There’s a choice of thicknesses available which is brilliant if you have a specific space to fill, between joists for example, and they have an amazing life expectancy with many brands expected to last the lifetime of the building it is put in. They're resistant to water vapour and fire and although they are one of the more expensive options, with a 2400mm by 1200mm board costing £66.71, they are a superb insulative material.

Insulation Rolls

Insulation rolls such as Knauf Earthwool Acoustic Insulation Rolls are made of glass mineral wool and, dependent on the thickness, typically have a u-value of around 0.044. They also have brilliant sound absorption qualities which is one of their big selling points.

Often chosen for the combined sound and thermal insulation capabilities that they provide insulation rolls are popular in residential buildings. The rolls can be used in walls, floors and roofs and are also a particularly brilliant choice if you have a long area to fill. For example, if you had a wide attic that you wanted to insulate, laying long rows down using an insulation roll would be much quicker and easier than using numerous insulation boards to fill the same space.

Insulation rolls are typically made from glass mineral wool and fire-retardant fibres and are non-combustible, preventing the spread of fire through your home. The glass mineral wool used in Knauf insulation rolls which you can purchase at Roofing Megastore is made from up to 80% of recycled materials, much of it coming from a glass recycling facility which is located next to the manufacturing plant making it a great eco-friendly choice too.

You can buy the rolls pre-cut in different thicknesses so that all you need to do is put them in place and each roll is incredibly lightweight making the process easy to complete. Per metre squared you can expect to pay around £1.65 for the Earth Wool making it one of the cheaper options for insulation.

Multifoil Insulation

Multifoil insulation is made up of a combination of foil which reflects the heat back into the building and wadding to insulate. This combination creates a u-value of 0.04 which is the equivalent to mineral wool but the difference is that multifoil insulation is much thinner.
Because multifoil insulation is so thin (just 35mm thick!) it’s perfect for use if you want to be as space efficient as possible. For example if you have an attic that needs insulation but you don’t want to eat into the space then multifoil is ideal and can be used for walls, floors and roof. Coming in large sheets it’s also incredibly easy to install and can simply be stapled into place. As an example of price, you can purchase a Actis Hybris Insulation Roll to cover approximately 5.49m2 from £23.45 at Roofing Megastore.

Other benefits of multifoil insulation is that it’s airtight and moisture resistant and it works to maintain the temperature in your roof space in both summer and winter, retaining warmth in winter and preventing overheating in summer this, along with the fact that it’s so thin makes multifoil insulation perfect for insulating your conservatory or similar small space.

Insulation Slabs

Insulation Slabs have an excellent u-value of just 0.034 and cost approximately £7.69 a squared metre. The resin bonded slabs are available in different sizes and thicknesses and are made up of naturally occurring renewable volcanic rock and are both sustainable and recyclable.

Insulation slabs are another product which offers both sound and thermal insulation, the slabs can be installed easily and when pushed together create a perfect friction fit, they can easily be pushed in between joists and are an easy option for a DIY project, ideal for loft and floor insulation they can also be used for walls.

Loose Fill Insulation

Loose Fill insulation is usually made of fiberglass or cellulose (recycled paper fiber combined with a fire retardant). One of the advantages of cellulose insulation is that it has the highest recycled content of any insulation available. It is usually blown or sprayed into place using pneumatic equipment and this makes it an ideal choice if you are using it for hard to reach areas. It is commonly used for attics or wall cavities and another advantage is that it can be used over existing insulation. Loose Fill insulation can also be cheaper than some other options. However, there are disadvantages, often you will need to hire a contractor to apply the loose fill insulation and because it doesn’t create an air tight seal it doesn't always straight away and can drift and settle in different areas to what you want it, leaving the insulation uneven.
If you already have insulation laid and are thinking of putting some more on top of it loose fill insulation is an ideal option. You can find more information on the benefits of laying new on top of old insulation.


Sprayed Foam Insulation

If you’re considering paying a contractor to install your insulation you also have the option of sprayed foam insulation. Sprayed Foam Insulation is sprayed on in liquid form and gradually expands up to 100 times its initial size, filling cracks and holes as it does. Spray foam insulation, depending on the thickness that is applied, typically has a u-value of 0.40 with a thickness of 40mm and a u-value of 0.16 with a thickness of 150mm.

Spray foam is usually made up of polystyrene and can give off harmful fumes when applied and so it is recommended that only an experienced contractor apply it. Also, if applied incorrectly it can actually damage your homes structure so it’s best left for the professionals.

It can be a costly option and you can expect to pay anything up to £45 per metre squared to achieve the same u-value as what mineral wool would provide you with.

More information

Hopefully this article has given you a little more information around the differences between the different types of insulation available but do give our friendly customer service team a ring if you’d like nay more information about any of the insulation products that we have available. You can reach them by phone on 01295 565565, online or by email.