Brent Pointon is the technical manager of Practica MMC, an Australian company specialising in External Insulation Finishing Systems and building envelope technologies for residential and commercial projects.
Architecture & Design spoke to him about what flooring insulation is, why it is important, as well as the advantages of BCA requirements.
What does ‘thermal performance of flooring’ mean?
Thermal performance is all about how energy efficient a certain product or system is. For example, in the summer, you need thermally efficient products or flooring systems to keep the inside of the house cool.
In winter, it works on the reverse – you’re heating the inside of your house, and you want to keep that heat inside and stop it from leaking outside.
Therefore, the higher the thermal performance of flooring, the more energy efficient it becomes, and the better insulation it has.
Why do some products have a better thermal performance than others?
Every material has some sort of thermal performance. Some materials, which we call insulation materials – products such as polystyrene, reflective foils, and also insulation blankets or fibreglass blankets – have a higher thermal performance than for example, the floorboards of your house. Compare the floorboards, which are very dense and thin, to polystyrene, which traps little bubbles of air, is very light and has a high insulation value.
A resistance value or an R value is given to each product to signify its level of insulation. A 20mm thick floorboard might have an R value of only 0.03, but a polystyrene panel used underneath that might have an R value of 2.0.
Any material which achieves better than R1.0 can be considered an insulator, but for example, a thermal rating is never attributed to carpet as it has only a small insulating effect.
Is there a maximum R Value?
No, it depends on how much you want to spend, and what you are trying to achieve. You can put incredibly high R values underneath floor systems, but there becomes a point when it becomes ‘overkill’.
For example, you might spend a certain amount of money to insulate a floor system to R2.0, which is the minimum dictated by the Building Code of Australia. In this scenario, you could spend three times that amount of money to get it to R6.0, but you might not achieve much more benefits in insulating the house, or keeping the house warm or cool.
The reason for this is that floors attribute up to 20 percent of your energy loss. You can have really high-performing insulation on the floor, but that’s no good if you have no insulation on your walls or ceilings. It’s all relative. You need to ensure that the whole envelope of the building is insulated really well.
What are the benefits of insulating floors?
It’s all about reducing the amount of energy that a house uses. With a well-insulated house, you literally start turning off air conditioning in the summer, or heating in the winter.
We have some pretty extreme temperatures around Australia. Western Australia for example can get very hot for a long period of time. The people in WA will leave their air conditioning units running all day long, and spend hundreds every month on energy to keep their house cool.
However, if you insulate the building envelope really well, you might be able to cut that energy use down to only two or three hours a day. That saves you a lot of energy, which means you are burning less coal or gas, and reducing your carbon footprint.
The building code prescribes a minimum of R2.0 for floors. Why is it important to have such a standard?
You lose up to 20 per cent of your energy – and thus power bills and costs – through your floors, depending on the type of floor that you have. Having a building code that says floors must be a minimum of R2.0 contributes to 20 percent of energy savings for your house.
Are there any other advantages for insulating floors?
The main advantage of insulating underneath floors is to save on energy and costs. The other advantage is that some forms of insulation can help to deaden or reduce the noise of walking on lightweight-type floors, such as a timber floor.
What about disadvantages?
There is not a disadvantage at all. It is purely an advantage to save money and energy. Obviously, it’s going to cost you money to insulate a flooring system, but you have to do so under the building code anyway.
The long-term advantage is that you save thousands of dollars over the life of the building. As long as that building is in existence, you can save a lot of money – that’s how insulation works. You might spend $5,000 insulating a house, but that insulation can save you thousands over the next 30 years. The cost of insulation is eventually off-set by the cost of energy savings.
Many people in Australia don’t place a higher value on well-insulated houses, but we should perceive 6 Star energy rated houses as being more valuable than houses with only 2 stars. People value a house with air conditioning over a house with no air conditioning. We should be looking at houses that have insulation; that will save thousands of dollars more in the long run.