All properties lose heat through the building fabric. The challenge is to reduce this as much as possible, which means that roofs, floors and walls all require attention – and insulation. Investing in appropriate insulation is one of the wisest choices you can make, and it’s an important cost to factor in right from the very start. It’s also an essential purchase if your project is going to be able to meet the required Building Regulations and as the stipulated targets can vary depending on the size and style of your build, and the requirements themselves often changing, it’s always worth double-checking before you buy.
The thermal performance of insulation can be measured by the U-values they can achieve, and generally speaking, the lower the U-value, the more heat retained. This can make a massive difference to energy costs – a well-insulated home will require less heating – and to the environment – as a more energy-efficient property will have a much smaller carbon footprint. Fortunately, there are several solutions available that not only meet current requirements but exceed them, which makes it possible to ‘future-proof’ your project and create a better long-term investment.
Big plan, small budget
It’s important to take a holistic approach to improve the energy efficiency of a home. So it may be appropriate to look at installing insulation in as many areas as possible. It, therefore, makes good financial and environmental sense to choose a multi-purpose product.
Traditional board insulation remains a popular choice owing to its cost-effectiveness, versatility and low thermal conductivity. Polyisocyanurate (PIR) boards are great all-rounders and can be used for various applications, including roofs and walls. Thanks to its high compression value, it can also be used as underfloor insulation, although it’s not suitable for rooms with heavy loads such as garages. An extra benefit is that the design of PIR boards typically includes a foil face to provide additional protection against moisture.
Insulation boards constructed using phenolic foam are also an excellent choice for projects where insulation is required in multiple areas. You can effectively use them to insulate floors, roof space and solid or cavity walls. Although usually a little more expensive than PIR board insulation, phenolic foam performs better and is excellent if you want to achieve low U-values but are limited in terms of space.
For projects with stringent environmental targets, or self-builders on the lookout for something a little different, there is the option of using products made from naturally-sourced or sustainable materials such as wool, hemp and recycled plastics.
Although the thermal performance of this type of material is not as competitive as others, it does offer a wide range of benefits and is suitable for use in walls, floors and to insulate loft spaces. Wool insulation, for example, has a natural fire resistance owing to the moisture in the fibres preventing it from igniting easily. It’s also easy to work with and can help reduce humidity and even absorb some atmospheric pollutants to help purify the air that enters a home.
A key focus on insulation is understandably its ability to help a property retain heat, but it’s also important to consider what happens when outside temperatures begin to rise. Often referred to as ‘space blanket’ insulation, multi-foil insulation is efficient at not only keeping your home warm during winter but cooler during summer. Using multiple layers of aluminium foil (hence the name) works by reflecting heat into its source and can effectively insulate walls, roofs and floors. The heat loss isn’t subject to the same diminishing returns as traditional insulation; however, it’s worth noting that you will need to consider an extra 25mm of space on either side of the insulation for it to perform at its best.
Don’t forget your floors
It’s usually only necessary to insulate at the ground floor level. Still, it’s worth considering adding insulation to any floors that are directly above any unheated spaces, such as garages or storerooms, to prevent additional heat loss. Polystyrene boards are a good choice for underfloor applications, but it’s essential to check their kPa rating, indicating how well the insulation can withstand extremely high pressure. The higher the rating, the more suitable the product will be for use under house foundations, in garages or for commercial or mixed-use buildings.
In older properties where access to the floor joists may be more of a challenge, using a flexible product like mineral wool insulation is much easier to handle and work with because it is formed in slabs rather than boards. This type of insulation is also an excellent fit for multi-storey properties. You can use it to insulate floors in between individual dwellings, such as flats and apartments, to reduce heat loss and limit noise transmission. As well as offering outstanding acoustic performance, the best mineral wool insulation also provides fire resistance for added peace of mind.
For most people, the choice of insulation will come down to two factors – where you’ll use it and how much you want to spend. However, if you spend a little more time looking at all the options available, it’s incredible how much you can save.