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2xMore Challenge

Hollow brick insulation

This topic contains 8 replies, has 3 voices, and was last updated by Profile photo of Mathieu VERDET Mathieu VERDET 1 year, 8 months ago.

  • Creator
  • #3499
    Profile photo of AADHITHYA

    My concept proposes the use of wood dust/wood shavings by filling it in hollow bricks used in construction of houses, especially for houses in non-equatorial regions where temperatures high at day and temperatures gets very low at night.

    Here wood dust will be mixed with anhydrous lime to preserve it. Here there is no chance of wood dust coming out from the hollow bricks as it is completely concealed. Though wood dust has been used for use in insulation earlier but it is used below wood panels and there was always problems associated with it. Using this approach inside hollow bricks it will be highly efficient and reliable.I have not found any similar concept which uses the wood dust inside hollow bricks anywhere so this makes the concept unique.

    Proof of concept

    “The sawdust was tested as an insulating material in the storage system and compared in its performance with the fibreglass wool storage system for hot water applications under similar conditions. From this study, it has been observed that the sawdust storage system also gave good performance for retaining the solar heated hot water up to the following evening. The solar water heating efficiency has been found to be in the range of 46.9-47.1% (fibreglass wool storage system) compared to 46.0-46.4% (sawdust storage system). The storage efficiency of retaining the solar heat for a night duration at different intervals of storage periods was observed from 61.5 to 65.5% (fibreglass wool storage system) and from 56.8 to 64.4% (sawdust storage system). Based on these investigations, the low cost and widely available sawdust may also be successfully employed as an insulating material in solar water heaters for retaining the hot water up to the following evening.”


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  • Author
  • #3516

    Maybe I don’t understand all parts of this concept but I see two high problemes with this combinaison. For me there is a very high probleme with the resistance to humidity. Bricks are permeable and ofen wet . So we have deterioration and rot of the wood dust. But bricks can’t also dry because there are the wood dusts. So they are an other deterioration. It is a vicious circle. In addition we have compression due to the materials.

    So for me this concept is noviable.

    Moreover, we can’t say that wood is performant in thermic inertia.

    Profile photo of AADHITHYA

    I understand ur concern that is the reason I have suggested to use anhydrous lime with wood dust to prevent rot. Hollow bricks are not completely permeable to water, else every house made with will leak right. It does adsorb some water when it rain continously but over the hollow bricks there are other layers as well, like a layer of cement, paint coatings. So water won’t be able to reach inside the bricks.

    If u think the problem will still persist I have a complete solution for it also, just fill each brick with a small plastic bag of wood dust/wood dust then no matter what water won’t be able to get in to rot it. So I think now the concept is viable and easily implementable.


    I agree that bricks are not completly permeable. It s just a language mistake, I don’t know the exact world to describe this phenomene.

    Your second proposition is fastidious but solve the problem.

    Profile photo of Mark Anson
    Mark Anson

    This is a great use of wood.  Have a look at Durisol, , who is a Canadian company that now produces a wood/concrete brick across North America.

    Profile photo of AADHITHYA

    Thanks for the link and information. That just gave an additional proof to the feasibility of my concept, the bricks can be insulated like they do pre built or after buying hollow bricks and filling them manually.


    Sorry but I disagree with you. It is not too easy.

    In the linked concept they use one material (mixture concrete with wood) for the bricks and add a small thickness of insulator. The interrogation is the same: humidity and condensation. But I think they make simulations and tests (I hope so) before validation of process. Moreover, I think personally that the R-value is bad.

    So maybe it is possible but I maintain my interrogations:

    –    Risk of condensation? Because you a combination of three layers or more.
    –    Risk of compression? Personally I think that is probable

    In addition, I maintain that wood is not a insulating materials with a conductivity of 0,13 W/m/K against 0,045W/m/K or less for other materials.
    I reflect also on your proposition of plastic bag. Finally it is not a really environmental solution and insects can destroy it.

    Profile photo of AADHITHYA


    The linked concept is already implemented and it is working well, they have taken care of the problems or concerns u r raising by properly testing it.

    Wood itself is a natural insulator due to air pockets within its cellular structure. As an insulator wood is 15 times better than masonry, 400 times better than steel, and 1,770 times better than aluminum. In addition, lightweight wood framing methods allow easy installation of additional fibre or foil insulation.Wooden windows are more thermally efficient as they do not form ‘thermal-bridges’ between the cold outside air and warm air inside (and vice versa in summer). Wood windows can be easily repaired and can be supplied in a number of colours or stains and built to a wide range of designs. Moreover we are making use of wood dust/wood chips which are otherwise burnt and hence it is very cheap.

    I agree wood won’t be able to match insulation properties like aerogel or other man -made materials but it is a gift from the nature, so it is almost free compared to other man-made materials which is very expensive.


    Yes I agree with you about it is better than many materials but for me as in the reglementation, a material is a insulator just if hits conductivy is less than 0,06 W/m/K. But I agree it’s just a detail.

    Finally, I not agree but now I understand your point of view.


    For me if we forget the potential problem of humidity and compression. They have lot of cost due to the implemention. So why not use a real insulator? The ratio cost/performance is better. Cellulose wadding are not expensive but very better for example.

    Moreover, can’t we use the raw materials directly to transform it in a insulator like a fiber panel…? I think there is a more improvement of the value. Unfortunatly, it’s out of the challenge^^.

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