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writing:building_materials [2025/12/04 23:35] – JacobCoffinWriteswriting:building_materials [2026/01/20 13:38] (current) – JacobCoffinWrites
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 Even concrete slabs can be [[https://www.finecutusa.com/concrete-slab-sawing-for-demolition-how-it-works/|cut up]] [[https://www.sciencedirect.com/science/article/pii/S095965262401014X|to produce new building materials]] or [[https://www.sciencedirect.com/science/article/pii/S0959652622048090|reused in creative ways]]! This is huge as concrete rubble accounts for [[https://concretecaptain.com/what-happens-to-concrete-after-demolition/|25]]-[[https://www.sciencedirect.com/science/article/pii/S095965262401014X|30%]] of solid waste in landfills.  Even concrete slabs can be [[https://www.finecutusa.com/concrete-slab-sawing-for-demolition-how-it-works/|cut up]] [[https://www.sciencedirect.com/science/article/pii/S095965262401014X|to produce new building materials]] or [[https://www.sciencedirect.com/science/article/pii/S0959652622048090|reused in creative ways]]! This is huge as concrete rubble accounts for [[https://concretecaptain.com/what-happens-to-concrete-after-demolition/|25]]-[[https://www.sciencedirect.com/science/article/pii/S095965262401014X|30%]] of solid waste in landfills. 
  
-Concrete rubble can also be reused in other ways, [[https://slrpnk.net/post/11909269|such as in landscaping]]. There's also a rich history of cobblestone buildings where concrete rubble may be a suitable [[https://www.mdpi.com/2075-5309/15/9/1437|replacement for stone]].+Concrete rubble can also be reused in other ways, [[https://archive.is/Mk8Ql|such as in landscaping]]. There's also a rich history of cobblestone buildings where concrete rubble may be a suitable [[https://www.mdpi.com/2075-5309/15/9/1437|replacement for stone]]. 
 + 
 +Tangentially related: [[https://phys.org/news/2026-01-urban-soils-life-excavated-dirt.html|this article]] discusses salvaging earth which has been excavated to make room for foundations in urban construction for use in parks and similar.
  
  
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   * Mass timber is lighter than traditional construction materials - this is great because the heavier the building, the deeper its foundation has to be. By reducing the weight of the building the designers can use even less concrete for the foundation. [[https://www.dezeen.com/2023/03/23/dalston-works-waugh-thistleton-architects-timber-revolution/|This example]] apparently weighs a fifth of a concrete building of its size, reducing the number of deliveries required during construction by 80 per cent (and allowing it to be bigger than it could have been due to a weight limit on the site).   * Mass timber is lighter than traditional construction materials - this is great because the heavier the building, the deeper its foundation has to be. By reducing the weight of the building the designers can use even less concrete for the foundation. [[https://www.dezeen.com/2023/03/23/dalston-works-waugh-thistleton-architects-timber-revolution/|This example]] apparently weighs a fifth of a concrete building of its size, reducing the number of deliveries required during construction by 80 per cent (and allowing it to be bigger than it could have been due to a weight limit on the site).
   * The wood structure can be constructed at a quicker speed compared to concrete- or steel-framed buildings of similar size. This also provides a cost-savings on the financial side, as that's fewer person-hours spent driving and building.   * The wood structure can be constructed at a quicker speed compared to concrete- or steel-framed buildings of similar size. This also provides a cost-savings on the financial side, as that's fewer person-hours spent driving and building.
-  * Timber is easy to cut and to build with, so the buildings are generally easier to adapt. This may make them last longer by making it easier to change them than to replace them.+  * Overall cost - these buildings are often actually cheaper to make than an equivalent concrete one, despite mass timber being a fairly new industry. 
 +  * Timber is easy to cut and to build with, so the buildings are generally easier to adapt. This //may// make them last longer by making it easier to change/improve them than to replace them.
   * Looks awesome - many of these buildings are genuinely impressive, with huge open spaces and interesting uses of the structural elements and natural wood making excellent use of the materials. Solarpunk isn't just aesthetics but good aesthetics certainly don't hurt.   * Looks awesome - many of these buildings are genuinely impressive, with huge open spaces and interesting uses of the structural elements and natural wood making excellent use of the materials. Solarpunk isn't just aesthetics but good aesthetics certainly don't hurt.
  
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   * Deforestation - humans are already erasing huge swaths of wild forest habitats from the earth - an increase in demand driven by a transition to mass timber could be disastrous, especially under capitalism (which ignores externalities and optimizes for the cheapest option) or when otherwise poorly managed.    * Deforestation - humans are already erasing huge swaths of wild forest habitats from the earth - an increase in demand driven by a transition to mass timber could be disastrous, especially under capitalism (which ignores externalities and optimizes for the cheapest option) or when otherwise poorly managed. 
   * Fire risk - these buildings can be very safe, but steel and concrete don't burn, and, under the right circumstances, wood certainly does. This means that the actual structure of the building can become fuel for a fire and that's something that has to be [[https://www.dezeen.com/2023/03/22/mass-timber-fire-safety-timber-revolution/|accounted for in the design]]. It seems likely that there's at least one of these buildings out there slapped together by architects who didn't bother to understand the differences in design required by their change in materials, just waiting to go up like a match, kill a bunch of people, and Hindenburg the entire concept of mass timber.    * Fire risk - these buildings can be very safe, but steel and concrete don't burn, and, under the right circumstances, wood certainly does. This means that the actual structure of the building can become fuel for a fire and that's something that has to be [[https://www.dezeen.com/2023/03/22/mass-timber-fire-safety-timber-revolution/|accounted for in the design]]. It seems likely that there's at least one of these buildings out there slapped together by architects who didn't bother to understand the differences in design required by their change in materials, just waiting to go up like a match, kill a bunch of people, and Hindenburg the entire concept of mass timber. 
 +
 +
 +===Mycelium===
 +
 +There have been several interesting projects looking to [[https://parametric-architecture.com/from-fungi-to-foundations-mycelium-in-construction/|turn fungus mycelium into a building material]]. 
 +
 +Sometimes this is a process of compressing and baking it into [[https://interestingengineering.com/culture/mycoblocks-mushroom-waste-homes-namibia|mycoblocks]] (large, solid brown slabs of oyster mushroom waste and invasive encroacher bush substrate), and sometimes it's a process of growing pieces of the house in big forms. 
 +
 +Mycelium has [[https://www.reddit.com/r/solarpunk/comments/1olkm5d/fusing_nature_and_architecture_the_mycelium|some appeal for solarpunk folks]] because it's a natural, sometimes carbon-negative building material which can be grown from organic waste products (like sawdust, or plant waste from agriculture) with a bit of mystique from mushrooms. 
 +
 +There are [[https://theconversation.com/we-think-of-mushrooms-as-food-but-mycelium-based-blocks-could-be-the-future-of-construction-269273|some challenges]] with producing consistent mycelium products, and there seems to be a bit of a search to see what mycelium will be useful for. 
 +
 +Mycelium construction materials aren't a drop-in replacement for concrete or brick - though they're strong for their weight they're quite a bit weaker in the same volume. They might be a closer fit for foamed concrete or clay brick.
 +
 +Most of the materials are biodegradable and also appear to not be waterproof without special coatings - this isn't unique (we build houses out of wood, after all) but it's something of an issue given that mycelium tends to be softer and its limits and performance in different climates is less well understood.
 +
 +Mycelium provides good thermal insulation so there are [[https://archive.is/vXbOe|some projects]] looking to use them to produce insulation, including to replace expanded polystyrene. This might be the easiest drop-in replacement to start out with.
 +
 +For now, it seems like this stuff is a little further out and we have less of an idea how we'll eventually use it. One thing I've noticed is that mycelium as a building material tends to show up in lots of [[https://www.archdaily.com/1035602/mycelial-hut-yong-ju-lee-architecture|showcase]] [[https://www.expats.cz/czech-news/article/mushroom-kingdom-czechia-unveils-world-s-first-fungi-based-house|projects]], [[https://interestingengineering.com/innovation/students-grow-igloos-from-mushrooms|student demos]], and [[https://parametric-architecture.com/from-fungi-to-foundations-mycelium-in-construction/|temporary outdoor pavilions]], but I've had some trouble finding finished examples like with Mass Timber and Geopolymers. 
 +
  
  
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   * Cob is a natural material and where used outside, will need upkeep and maintenance, especially in wet areas as rain can wash it away. Many designs call for large, overhanging roofs and special coatings to protect it (and some, like lime, may take more CO2 to produce than expected). There are some [[https://www.reddit.com/r/solarpunk/comments/1ccz8qb/waterproofing_cob_houses_adobe_and_compressed/|other interesting ways]] to waterproof it.   * Cob is a natural material and where used outside, will need upkeep and maintenance, especially in wet areas as rain can wash it away. Many designs call for large, overhanging roofs and special coatings to protect it (and some, like lime, may take more CO2 to produce than expected). There are some [[https://www.reddit.com/r/solarpunk/comments/1ccz8qb/waterproofing_cob_houses_adobe_and_compressed/|other interesting ways]] to waterproof it.
  
-**Salvage:**+**Salvage in cob buildings:**
  
 There are some interesting opportunities for salvage in a cob structure. The foundation is often a trench filled with 'rubble' - this is usually fieldstone but there's no reason it couldn't be actual broken up concrete, which would otherwise end up in a landfill.  There are some interesting opportunities for salvage in a cob structure. The foundation is often a trench filled with 'rubble' - this is usually fieldstone but there's no reason it couldn't be actual broken up concrete, which would otherwise end up in a landfill.