EPS is dead long live to GraphiteEPS

This might be one of the more technical posts. Since this blog is still in its cradle, constantly evolving, you might find  funny, thoughtful or technical posts here. However, I will try to keep all information as much accessible for anybody interested. If you have your opinion how should I steer my blog you are welcome to leave a comment or write me a mail.

On a building site at Tusinfryd, I stumbled upon a sample of graphite extruded polystyrene glittering in the morning sun. Distinguished by its grey colour. However otherwise seemed like the normal polystyrene. I must admit I have never seen this kind of polystyrene before, and therefore I checked it up and actually write a part of our building site report about it.


Normal polystyrene has been used for insulation for a long time. In Denmark mostly for insulating under the floor slab, in many countries, it is used on walls from outside as well. Standard polystyrene insulates quite well and it lasts very long time, probably longer than nature would like, but in construction, its longevity is a plus.

In recent years, new technique during a manufacture of polystyrene has been invented. Each foam bubble is coated in graphite power. Graphite further increases the insulation properties of the polystyrene, because it reflects the heat back.

This made me very interested, so as a part of research and because I had to write building site report I delved deeper into this process.

I found a company which makes both standard and graphite polystyrene and made a comparison based on premise that I want to achieve certain U-Value (that is a fancy technical word which describes how well certain materials insulate).

Below you can see that I wanted to achieve U-value of 0,15. And from my calculation, we can see that the graphite polystyrene is about 3% more expensive per same insulation properties. But that’s not the whole conclusion. Aaaaand since I spend quite a lot of time with that I will do one amazing thing. I will quote myself (evil laugh). Isn’t that amazing thing you can do?


From my calculation, we can see that both kinds give us nearly the same U-value to price ratio. Expanded polystyrene has the ratio slightly better. However, we can assume, that by using graphite expanded polystyrene we are cutting down the transportation cost since we have to transport around 20% less volume. Also, there might be a small difference in labour cost, since we have to move less volume of insulating material around the building site. Same is true for the excavation process since we do not have to dig that deep, which is another slight advantage which cuts down overall construction price by a small percentage. The last thing might also be the construction thickness. When we do not have the luxury of simply digging deeper, we might use graphite polystyrene when we need thinner construction, e.g. insulating of the floor above non-heated basement. All those advantages give an edge to the use of graphite expanded polystyrene. And since the company building the house we are observing builds hundreds of similar houses, they probably calculated these advantages as well and in order to cut down the construction cost and maximise their profit, they decided to use graphite expanded polystyrene. The difference might not be much, but details make the difference when they are put together. As a conclusion, we might see, that the advantages of graphite polystyrene are subtle. However, even small advantage makes difference, especially in larger quantities and therefore I would recommend using graphite expanded polystyrene instead of normal expanded polystyrene. (Slunecko, 2017)

However don’t take that too seriously. But seriously, graphite expanded polystyrene is amazing and I believe it should be used basically everywhere normal polystyrene can be used.

Like below, graphite polystyrene used in a foundation block. Bang boom win win. Superinsulation!IMG_0383

And as with standard polystyrene, easy manipulation, cut with a hot wire cutter. Very useful and universal insulation material. I strongly encourage its use. Its super cool to use the best you can get. Once you go grey you never go back.


Happy insulating




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