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--- writing:building_materials [2025/12/03 23:29] – JacobCoffinWrites
+++ writing: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.
-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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 That said, a solarpunk society is likely one that actually tracks its externalities and tries not to produce waste it can't account for, and once you factor in the true costs of Portland cement, the mining, the transportation, the CO2 production, geopolymers are a rather straightforward replacement.
+=== Mass Timber Constriction ===
+Mass timber is the name given to the various different types of engineered wood that can be used as structural building materials in place of steel and concrete. It's popular in solarpunk-adjacent spaces because it can be used to make modern skyscrapers and other big buildings with a far lower carbon footprint. This is partly because steel and concrete are CO2-heavy industries, and almost any alternative is an improvement there, but also because cutting down trees and using them to build buildings sequesters the carbon they captured from the atmosphere (at least for the lifetime of the building). This means that a mass timber building could even be carbon-negative if done correctly.
+And that's kind of the theme with these buildings - if they're done right, they can be an absolutely awesome tool for mitigating the climate damage we're causing, and if done poorly, they can be incredibly environmentally damaging and possibly quite unsafe.
+There are a ton of different configurations for which way the wood is arranged and fastened together to form these big structural beams and panels, and you can find lists of them [[https://en.wikipedia.org/wiki/Engineered_wood#Mass_timber|here]] and [[https://www.dezeen.com/2023/03/01/dezeen-guide-mass-timber-revolution/|here]]. The materials are usually made in factories and engineered to precise specifications and assembled onsite.
+**Advantages:**
+  * When it's harvested [[https://www.dezeen.com/2023/03/24/t3-mass-timber-building-michael-green-architecture-timber-revolution/|sustainably]] (and ideally locally to reduce CO2 released in transportation, and when the manufacturing process is efficient) mass timber is carbon negative. But even if it only breaks even it'd still be an improvement over concrete and steel.
+  * 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.
+  * 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.
+**Disadvantages** / things to account for in your setting:
+  * The carbon-negative potential of the timber can be offset by a few things:
+      * The other materials used in construction [[https://www.dezeen.com/2023/03/30/amy-leedham-interview-mass-timber-revolution/|can offset]] the carbon savings of the wood if they're not chosen carefully.
+      * The carbon footprint of mass timber [[https://www.dezeen.com/2023/03/31/mass-timber-carbon-assessment-timber-revolution/|is impacted by how and from where the wood was sourced and transported.]] Poor timber harvesting practices can be incredibly destructive and release tremendous amounts of carbon from forests.
+      * If the wood used in a building's construction ends up in a landfill, it is likely to be incinerated or left to decompose, with its sequestered carbon released back into the atmosphere – cancelling out the carbon benefits. Because so few mass-timber buildings have been constructed – let alone demolished – researchers are also unable to reliably forecast what will happen to engineered timbers at end of their life and what emissions this would entail. Salvage and [[deconstruction|deconstruction]] could play a huge role here in keeping this carbon sequestered by reusing these structural timber elements.
+  * 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.
+===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.
 ===Regional Options ===
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 === Cob ===
-[[https://www.motherearthnews.com/sustainable-living/green-homes/cob-building-basics-zm0z13onzrob/|Cob]] is the British term for a traditional building material/method which has been used for thousands of years and was invented independently by people on multiple continents. It involves creating a mix of clay, sand, water, and straw or other fiber, and building it up and shaping it into a structure in multiple layers. It's a cheap, low-carbon construction method which can build comfortable homes out of local (often even local to the build site!) materials. Cob lost popularity in many regions during industrialization, but has seen a resurgence in popularity recently with [[https://en.wikipedia.org/wiki/Earthship|earthship]], owner-built, and permiculture/self sufficiency movements.
+[[https://www.motherearthnews.com/sustainable-living/green-homes/cob-building-basics-zm0z13onzrob/|Cob]] is the British term for a traditional building material/method which has been used for thousands of years and was invented independently by people on multiple continents. It involves creating a mix of clay, sand, water, and straw or other fiber, and building it up and shaping it into a structure in multiple layers. It's a cheap, low-carbon construction method which can build comfortable homes out of local (often even local to the build site!) materials. Cob lost popularity in many regions during industrialization, but has seen a resurgence in popularity recently with [[https://en.wikipedia.org/wiki/Earthship|earthship]], [[https://www.reddit.com/r/solarpunk/comments/1icgncm/do_you_know_any_solarpunk_architects_that_design/|owner-built]], and permiculture/self sufficiency movements.
 The flowing, sculptural shapes of the buildings, gives them a fantastical, sometimes fairy-tale vibe, and they're often decorated with bas reliefs, mosaics, or other artwork.  And cob is used for more than just walls - people sculpt in all kinds of clever nooks and shelves, stairways, seating and even fire places and stoves. This extreme customization is an excellent rejection of the resale value pressure to treat our homes as products, best kept generic and free of any permanent personalization.
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 **Disadvantages:**
-  * Cob isn't a great fit for every region. It does not have a very high insulation value per thickness and most of its temperature regulation benefits are done via its mass. This is great for places where the temperature swings between hot days and cold nights, but if it's freezing outside day and night for months or perpetually hot and humid, this mass and inertia may work against you as you try to maintain a comfortable temperature indoors. For more discussion on where cob makes sense, https://www.greenhomebuilding.com/QandA/cob/where.htm#:~:text=Generally%20I%20would%20not%20recommend,for%20cob%20in%20every%20climate
+  * Cob isn't a great fit for every region. It does not have a very high insulation value per thickness and most of its temperature regulation benefits are done via its mass. This is great for places where the temperature swings between hot days and cold nights, but if it's freezing outside day and night for months or perpetually hot and humid, this mass and inertia may work against you as you try to maintain a comfortable temperature indoors. You can find more discussion on where cob makes sense and how to account for local conditions [[https://www.greenhomebuilding.com/QandA/cob/where.htm#:~:text=Generally%20I%20would%20not%20recommend,for%20cob%20in%20every%20climate|here]].
       * In particularly cold, wet regions, cob is sometimes used for interior walls and structures, while more 'normal' insulated walls are used on the exterior. Cob is a popular way to build thermal mass heaters and [[https://insteading.com/blog/rocket-mass-heaters/|rocket]] [[https://commonsensehome.com/rocket-mass-heaters/|mass]] [[https://permies.com/t/265979/dry-cob-rock-solid-frame|heaters]].
   * Many regions have strict building codes written around modern construction practices. Cob buildings generally aren't included in these regulations and may be specifically excluded, leading to time and money wasted changing the codes and educating lawmakers, awkward workarounds like only building small 'accessory' buildings, or just building illegally.
-  * 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).
+  * 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.
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 **More info:**
-Sometimes seeing real life discussions between people using a solarpunk practice can provide some perspective and ideas - here's a handful of forum threads on cob construction https://permies.com/f/76/cob
+Sometimes seeing real life discussions between people using a solarpunk practice can provide some perspective and ideas - here's a handful of forum threads on cob construction: https://permies.com/f/76/cob
-=== Mass Timber Constriction ===