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Beating Them At Their Own Game: Why LEGO Makes Good Insulators

Beating Them At Their Own Game:  Why LEGO Makes Good Insulators

At the end of last year, a paper was published, highlighting the extraordinary performance of LEGO bricks for insulation at cryogenic temperatures (that is, really really cold). In this post, we are going to explain what that research did, explain why LEGO performed so well, and look also at the practical applications of the research.

LEGO Block Structures as a Sub-Kelvin Thermal Insulator – Research by the University of Lancaster

A research lead by Dr. Dmitry Zmeev explored the thermal properties of LEGO Block Structures at cryogenic temperatures. Those are temperatures near the absolute zero (minus 273.15 degrees centigrade). Currently, very expensive materials (such as Macor or Vespel) are used to insulate machinery that needs to be maintained at these temperatures.

What the research team found out is that LEGO Block Structures have better thermal isolation than well-known bulk insulator materials in the explored temperature range, whilst maintaining solid support.

Explanation of why LEGO is such a good insulator at low temperatures

The research suggests that the high performance of LEGO can be attributed to the high resistance solid-solid connection between blocks. What this means is that, because the blocks fit so well between them due to the low tolerance that LEGO uses, that creates a structure with voids in between that are in a vacuum, increasing dramatically the insulation properties of the block.

So, if instead of combining four blocks, only one block was used, the piece would not work at all because it is in the connection between the pieces that the “magic” happens.

The research team goes about suggesting that, since the result comes mostly due to how well the pieces interlock, there is no reason why the same principle could not be used with other polymers.

Applications of this finding

What this finding means is that a similar shape and principle could be used in order to design specific insulation materials for those temperatures that could be much much cheaper than what it is currently on the market.

As we said, the “magic” happens in the interlocking between the different bricks and not on the specific material that LEGO bricks use. This material is commonly referred to as ABS (Acrylonitrile butadiene styrene). So, by understanding and isolating those principles, new insulations could be designed that use much better insulation materials but that are still much cheaper than the current standard options on the market.

Characteristics of ABS that make it a good insulator

So, even though ABS is not the perfect material, it still has some good properties that helped in the result of the study and that can also make ABS a good insulator for earth-related temperatures.

To give you an example of the order of magnitude we are talking about, commonly used building insulators such as rock mineral wool, glass mineral wool, or Expanded polystyrene (EPS) have a Thermal conductivity of between 0.03 and 0.04 W/(m*K). ABS, on the other hand, has a thermal conductivity of 0.25 W/(m*K). This might seem high, but it is not so high if you compare it to other common building materials such as concrete (thermal conductivity of around 1 W/(m*K)) or stainless steel, with thermal conductivity of over 16 W/(m*K).

Is LEGO a good option for human-scale constructions?

With the values explained above, you might think that it makes no sense to use LEGO as an insulator for earth-related temperatures. However, the thermal conductivity that we gave above for the ABS does not take into account the interlocking “magic” of the LEGO blocks, which was what made the LEGO bricks perform so well in the study.

According to that study, the thermal conductivity for the temperature range of the experiment (from 70 mK to 1.8 K) was about 0.00000083. This does not mean that the same built-up would have the same properties in a room temperature environment, but you can see how different the thermal conductivity is compared to the elements we discussed before.

That would make LEGO a much better alternative than anything in the current market. However, there are no studies done that have tested the performance of LEGO in more normal temperatures, so it has not been confirmed that this excellent performance would also happen in our temperature range.

In addition to that, it is worth remembering that LEGO bricks do not perform well in warm environments. If a LEGO brick gets heated up over 104°F / 40°C, it will most likely deform and the “magic” of a perfect interlocking fit will disappear. That will cause the performance of the LEGO brick to decrease dramatically.

Another downside of using LEGO bricks as an insulator material for human-scale constructions would be increased cost because of material and labor.

As far as material is concerned, LEGO bricks are not a very cheap option, even as toys. As we explained in our post “Why is LEGO so expensive? (And alternatives to consider)”, LEGO has invested a lot into quality control and into making its bricks consistent so they can interlock with bricks of any year. That comes in handy when you use them as toys, but some of it is an unnecessary expense if it needs to be used as an insulation material.

As for the labor, just imagine the amount of time it would take to connect all the bricks so that it insulates a wall. LEGO bricks are sized to be used as toys and not to be covering full facades. Therefore, they would become a very labor-intensive task, which would increase the cost even further.

You might think that also covering a full facade will not be possible because of the weight of the LEGO bricks. Well, according to a study done by researchers at the Open University in 2012, it was found that an ordinary-sized Lego brick can support the weight of 375,000 other bricks before it fails.

The study mentioned above regarding the insulation also tested LEGO’s mechanical properties and found out that one LEGO brick was able to withstand ≈300 kg of load in a hydraulic press before failing. So, as you can see, the mechanical properties would not be a problem.

But what about using the principles that make LEGO bricks such good insulators and apply them in a way that they work well with the building environment?

Examples of companies doing LEGO-like bricks to achieve better insulation

Well, even though there is not a single company that has taken the exact same approach that LEGO has, there are some that are following these principles. We have listed below the four approaches that seemed to us more interesting, but they are not by any means the only ones.

Insulating Concrete Forms (ICF)

The most widespread system which is similar to LEGO bricks is ICF, which is short for Insulating Concrete Forms. With this system, rigid thermal insulation that stays in place as a permanent interior and exterior substrate for walls, floors, and roofs is used. This insulation is made of forms that are stacked without the need to use mortar. Once in place, they are filled with concrete. The units lock together like LEGO bricks and a great performance is achieved.

This type of construction is becoming more and more common and it is being used for both low-rise commercial buildings and high-performance residential buildings. As more energy-efficient and natural-disaster-resistant building codes are adopted, the use of this system should keep increasing. The only doubt about the system is the use of concrete, which is proven to be the worse material for sustainability.

Most companies out there use a very similar interlocking system, with the pictures from the product looking basically the same. The following are some companies that use this system:

Kite Bricks

This revolutionary system had some very bold statements and was supposed to revolutionize the building industry. However, it seems dead in the water since 2017, so we are not completely sure if they are still operating. In any case, the idea is very interesting so we want to feature it here.

This company, Kite Bricks developed a product that they named “Smart Bricks” (S-Bricks). These bricks were made out of high-strength concrete and the idea was to use these bricks to make buildings rapidly, cheaply, and energy-efficiently. These bricks were patented at the end of 2014 as can be seen in this link.

The bricks are like LEGO bricks, in the sense that they come in a variety of forms for different purposes and can be easily connected together. Unlike LEGO, though, these bricks require an additional element to fix them together. In this case, it is a special adhesive, a bit like a super-strong double-sided sticky tape. This, however, has the advantage of removing the need to use cement to fix the bricks, material usually needed for traditional concrete blocks.

To make these bricks even more resistant, steel bars can be slotted through dedicated channels within the bricks. This will provide the same support as reinforced concrete.

These bricks have an open space for insulation. Thanks to that, a building built with this type of brick will require less energy for heating and cooling. This space also allows for elements such as plumbing or wiring to be installed in them. These bricks also feature removable panels and allow for easy access to these elements. This ensures that portions of the walls don’t need to be demolished if certain maintenance is required.

According to the website, there are different bricks that can be used to build floors, walls, and ceilings. This allows for facile, solid construction with little mess and significantly reduced construction costs.


The next company is called Brikawood. As you may have guessed from the name, in this case, the interlocking bricks are made of wood. We are really excited about this one because it is also a very sustainable option.

Because of the way that the interlocking bricks have been designed, builders can assemble and disassemble the walls without having to use glue, nails, or screws. The space in between the wood-brick is filled with wood shavings left over from the manufacturing of the Brikawood bricks. These wood shavings act as the insulator, insulating both temperature and sound.

These bricks are done from Douglas eco-certified wood – class 3. According to the website, the construction will be water & air safe within 4 weeks with their professionals’ skills. The insulation follows the RT 2012. Since this insulation is made from the leftovers from the manufacturing of the Brikawood bricks, the entire production results in a nearly zero waste.

You can either buy studio kits, which allows you to build a 20m2 space, or you can buy full houses. Models and sizes depending on where you live.

Conceptos Plásticos

The next and last company from the list is Conceptos Plásticos. This company from Colombia is doing something quite unique and extraordinary. Basically, they are taking two of the biggest problems that humanity is currently facing, plastic recycling and affordable living and found a solution that tackles both.

The idea being Conceptos Plásticos is to recycle the plastic that would otherwise end up in landfills or in the oceans and use it to create LEGO-like bricks. With this solution, they upcycle the plastic, meaning that they recycle and create something of a higher value.

For those worried about safety, Conceptos Plásticos adds a product that makes the blocks fire-resistant. According to the company, the construction system using these bricks is 30% cheaper than systems traditionally used in rural areas, with the added benefit of recycling plastic that would otherwise pollute the environment.

They work with local communities, where they source the plastic and rubber they use to create the bricks. And they train the locals on how to build their own houses so the solution is as affordable as possible. These bricks can be used to build not only houses but also emergency shelters, classrooms, and community halls.

According to this source, a home for one family would take four people five days to build using these recycled building blocks. What is more, because of how simple they are to put together, there is no construction experience required in order to place them

Last words

And with this last example, we have arrived at the end of this post. During this post, we first had a look at the interesting research done by the University of Lancaster, where they found out that LEGO bricks worked much better as an insulator than the most common (and much more expensive) materials that are currently used.

We then had a look at why this happened and which lesson could be applied to everyday life insulation. We then had a look at whether LEGO would be a good option for insulation buildings in real-life scenarios and we ended up showing some examples of companies doing LEGO-like bricks for the construction industry.

If you like this post, be sure to check other informational posts such as “Recycling LEGO: Possible Or Not?” or “Debating The Educational Nature Of LEGO”.

Learn More

If you are interested in any big Lego ideas, then check out this Lego Ideas book on Amazon.