#Cob, a #vernacular earth #construction process in the context of modern #sustainable building

Erwan Hamard, et al.

"The will of reducing environmental and social impact of building industry has led to a renewed interest in #EarthConstruction. Most of earth construction literature dealt with #RammedEarth or #Adobe techniques, but very little with cob. Yet, cob participates in the diversity of #vernacular earth construction processes that value local materials and is an alternative to rammed earth and adobe in specific geographical conditions.

"#Conservation of cob heritage also requires a better knowledge of this vernacular construction process. This bibliographical analysis gathered extensive data on cob process and summarized the different cob process variations, attempting to take into account their diversity. This analysis allowed us to provide novel data on cob process, and more specifically, a clear definition of cob with regard to other earth construction processes, a first summarized description of cob process that clearly distinguished its variations, a list of fibres traditionally employed, values and, if possible, average and standard deviation for fibre length, fibre content, manufacture water content, drying times, lift heights and wall thicknesses, a summary of the strategies to manage shrinkage cracks, a criterion on the quality of implementation and/or earth for cob, based on slenderness ration of lifts and a discussion on the evolution of cob process with regard to societal evolutions."

https://www.sciencedirect.com/science/article/abs/pii/S0360132316302165

#SolarPunkSunday #SustainableMaterials #AncientTechnologies #Adaptation #SustainableConstruction #CobBuilding #BuildingMaintenance #HistoricPreservation #Restoration #NewBuildingTechniques #History #Science

So, this isn't a #Kiln (it is only spec'ed to 700 F), but it could be useful for cooking food.

How To Build Your Own #CobOven – Step-by-Step

Written by Author Cheryl Magyar Published on February 27, 2024

Excerpt: "earth ovens work – and bake well – because the heat generated by burning wood is absorbed into the thermal layer of the oven. Then that radiant heat is evenly released through the air, while conduction (from the contact of the bread dough on the hot bricks) and convection (hot rising air) play a part in the thorough baking process too.

But why would you want to build an earth oven when you already have a place to bake in your kitchen?
Well, you might want to build a cob oven because:

it has the chance to become the centerpiece of your outdoor living space – where family and friends gather to eat well, laugh and create long-lasting memories in nature.
clay is an abundant material to work with.
the wood you burn can be sourced locally, plus it’s renewable.
cob ovens are a low-impact alternative to gas or charcoal.
it gives you the chance to apply your artistic and creative abilities to a functional object.
it promotes self-reliance – you still get to bake, even if the power is out for a prolonged period of time.
food cooked in cob ovens tastes better, you’ll have to try it to find out.
you love pizza, or bread, or baked meat."

Learn more:
https://www.ruralsprout.com/cob-oven/

#SolarPunkSunday #DIY #Homesteading #TraditionalTechnology #EarthOvens #WoodFiredOvens #AncientTechnologies #NaturalBuildingMaterials

#India - How to Make #Lime From Scratch

25/12/2018

Making Lime from Scratch - An Overview

1. Build a kiln from cob, or some other material that can stand 1000 degrees heat.

2. Collect some oyster/clam shells, or limestone (see video below).

3. Light a fire in your kiln and add your limestone/shells. Get the temperature up to between 800 and 1200 degrees.

4. Extract the shells (if using) and put them in a vat.

5. Put on protective clothing (mask, goggles, gloves, onesie etc)

6. Add warm water to the burned shells and watch the mixture bubble and froth. Be careful. Lime is caustic and can burn.

7. The longer you leave that substance slaking (submerged in plenty of water), the better quality lime you get.

"Lime. Oh lime. So versatile. So useful. But sometimes so difficult to know which kind you’re buying. You may remember my beginners' guide to different kinds of lime I penned last time. Sometimes though, all the CaOs and NHLs in the world won’t help you, because you live in a place that doesn’t regulate too carefully, and your lime turns up in mysterious dog-eared bags which inspire anything but confidence.

In that case you can always do what Gautam Singh in Mumbai did. Cut out the middle man, and make it yourself. He shared his process in our members' only Facebook Group last week, and I think it's fabulous.

" 'Unsure and concerned about of the quality of lime we were purchasing, especially for some tadelakt work, we made a small kiln to make our own lime,' says Gautam, who is still battling on with plaster work over there in Mumbai. I’ve got to hand it to him, he’s not a quitter:)

'It's specifically for tadelakt,' he says, and 'I’m happy to say it works, and wasn’t too complicated or time consuming either.' Oh...music to my ears!

How did they create their own quick lime?
First Gautam and his friends built the kiln out of cob (see above). Next, he collected a bunch of oyster and clam shells from seafood sellers. You don't crush the shells, they are left whole so they are easy to identify post burning, because the entire burned shell will be converted into Calcium Oxide or pure lime.

'Research stated the shells needed to be fired between 800-1200℃. Any less and it wouldn't have the reaction that turns it into lime, and any more would melt the shells,' he informed us.

I asked him how he measured the temperature. 'Figuring out the temperature was tricky at first, but luckily a professional #potter friend came to the rescue and we used a #thermocouple to measure the temperature for the first two trials. After that it became easier because then I knew it took between 40-60 mins to achieve that 800-1200 degrees required for my kiln.'

Initial Troubles

In the beginning Gautam thought he'd failed. But in fact it's a good example of how things are sometimes not what they appear. 'After our first firing attempt, we went through the burnt matter, extracted all the shells and put them in a pot. Then we tried adding water. But there was no reaction!'

Our pioneer thought perhaps he hadn’t fired the shells at a high enough temperature. He prepared his kiln for a second attempt. It was then he chanced upon a golden nugget of online information advising the use of warm water (not cold) to slake the burnt shells. The Mumbai team decided to try it.

'So we used the same shells, added warm water and voila! It started boiling and reacting violently,' he says."

Read more:
https://www.themudhome.com/mudbuilding/how-to-make-lime-from-scratch

#SolarPunkSunday #SustainableMaterials #Quicklime #AncientTechnologies #Science

Ahhhh... Using a hand-drill to start a fire. Now that takes me back to my days at the Wilderness School! I'd love to try and make a pottery-kiln (I'll be researching that soon...)

#Australia - Making #lime with Primitive Technology

"When heated above 840 degrees Celsius, the lime decomposes into calcium oxide (CaO) or #Quicklime and releases carbon dioxide (CO2). When water is added to the quicklime it becomes calcium hydroxide Ca (OH)2 or #LimePutty. From here the calcium hydroxide can then be shaped into a form and allowed to set.

Carbon dioxide enters the lime putty as it dries causing it to turn back into calcium carbonate. The new calcium carbonate has then set, remaining solid and water resistant.

In my local geography, calcareous rocks such as limestone are absent leading to a difficulty in acquiring the feed stock for lime making. However, I was still able to make lime by collecting the shells of large terrestrial snails that are native to the rainforest here. The unoccupied shells of these snails were gathered up and stored at the hut. Fire wood was gathered and packed neatly into the kiln.

Importantly, the firewood was stacked on top of the grate rather than underneath it in the firebox as is the normal procedure for firing pottery. Using an ordinary updraft pottery kiln in this configuration allows it to reach much higher temperatures than would be possible during normal use. The wood was lit from above and the fire burned down towards the grate. Alternate layers of shells and wood were added on to this burning fuel bed. After adding the last layer of wood to act as a 'lid' to prevent heat loss from above I left the kiln to finish on its own, unsupervised. The whole process took about an hour and a half.

When the kiln had cooled down a few hours later, I took out the calcined shells. Not shown in the video was the fact that some shells got so hot, the dirt stuck to them turned into slag and fused to them, possibly with the lime acting a flux lowering its melting point. This extreme heat (+1200 c) should be avoided as the over burnt lime becomes 'dead lime', unable to slake in water. Most shells were still useable though. They were taken out of the kiln and had water added to them.

An exothermic reaction then ensued. Heat was produced as the lime quicklime turned into slaked lime. The water heated up creating steam and the shells decomposed into a white paste. The paste was stirred and crushed pottery was added to it as an aggregate (sand is normally used for this, I just had a lot of old pot sherds lying about to dispose of).

This lime mortar mixture was then formed into a block shape and left to dry. It took about a week and a half to set as we have had extremely humid, wet weather. The block was observed to have set demonstrating its properties.

What I created is actually lime mortar, typically used for mortaring bricks and tiles together. It’s basically the ‘Glue’ that holds together the building blocks of masonry structures. From my research 20 kg of lime mortar is used on a 1 m square section of brick wall. 5 kg of lime to 15 kg of aggregate (sand, grog etc.) per a 1 m square section of bricks. The shells, though large, are not terribly abundant. A method for finding shells efficiently needs to be made before considering making lime mortar in this fashion. From my experience sand bars in a creek sometimes accumulate snail shells from higher up in the mountains. In these spots, water velocity decreases and shells in the water tend to drop out of the water column. Additionally lime may be partially replaced with ordinary wood ash in mortar without a corresponding decrease in strength. To conclude, making lime in a land without limestone is possible but can be problematic when trying to do so on a large scale."

Watch:
https://thekidshouldseethis.com/post/making-lime-with-primitive-technology

YT:
https://www.youtube.com/watch?v=Ek3aeUhHaFY&t=46s

Wordpress:https://primitivetechnology.wordpress.com/

Patreon page: https://www.patreon.com/user?u=2945881

#SolarPunkSunday #SustainableMaterials #TraditionalTechnology #ZeroWaste #Mortar #LimeMortar #Snailshells #Adaptation #AncientTechnologies #Science #AnimalProducts #LocalMaterials

Ancient Egyptian ‘Air Conditioning’ Could Help Cool Modern Buildings

One research team hopes to harness 5,000-year-old ideas to battle rising temperatures.

By Andrew Paul, August 22, 2023

"While the planet continues to endure scorching, unprecedented temperatures, a 60-square-foot shipping container is serving as a testing ground for passive, sustainable cooling solutions. As detailed in a 2023 study published in the research journal Energies, an engineering team at Washington State University utilized the space to find and improve upon ancient cooling methods that don’t generate any forms of greenhouse gas—including water evaporation atop repurposed wind towers.

"Buildings require roughly 60 percent of the entire world’s electricity, almost 20 percent of which is annually earmarked to keep those structures cool and comfortable. As society contends with climate change’s most ravaging effects, air conditioning systems’ requirements are only expected to rise in the coming years—potentially generating a feedback loop that could exacerbate carbon emission levels. Finding green ways to lower businesses’ and homes’ internal temperatures will therefore need solutions other than simply boosting wasteful AC units.

"This is especially vital as rising global populations require new construction, particularly within the developing world. According to Omar Al-Hassawi, lead author and assistant professor in WSU’s School of Design and Construction, this push will be a major issue if designers continue to rely on mechanical systems—such as traditional, electric AC units. 'There’s going to be a lot more air conditioning that’s needed, especially with the population rise in the hotter regions of the world,' Al-Hassawi said in a statement.

" 'There might be [some] inclusion of mechanical systems, but how can we cool buildings to begin with—before relying on the mechanical systems?' he adds.

"By retrofitting their shipping container test chamber with off-the-grid, #solar powered battery storage, AL-Hassawi’s team can heat their chamber to upwards of 130 degrees Fahrenheit to test out their solutions while measuring factors such as air velocity, temperature, and humidity. The team is particularly focused on optimizing a passive cooling method involving large towers and evaporative cooling that dates as far back as 2,500 BCE in ancient Egypt. In these designs, moisture evaporates at the tower’s top, which turns into cool, heavier air that then sinks down to the habitable space below. In the team’s version, moisture could be generated via misting nozzles, shower heads, or simply water-soaked pads.

" 'It’s an older technology, but there’s been an attempt to innovate and use a mix of new and existing technologies to improve performance and the cooling capacity of these systems,' explained Al-Hassawi, who also envisions retrofitting smokestacks in older buildings to work as new #CoolingTowers.

" 'That’s why research like this would really help,' he adds. 'How can we address building design, revive some of these more ancient strategies, and include them in contemporary building construction? The test chamber becomes a platform to do this.' "

Source:
https://getpocket.com/explore/item/ancient-egyptian-air-conditioning-could-help-cool-modern-buildings?utm_source=firefox-newtab-en-us

#AncientTechnologies #SolarPunkSunday #CoolingSolutions
#ExtremeHeat #AncientTechnology #ClimateChange

#Ancient #Architecture Might Be Key to Creating Climate-Resilient Buildings

Vernacular architecture is a way to use a region's heritage and resources to build strong homes and cities.

by Angely Mercado

"The United States has braved a year of multiple billion dollar weather disasters over the past couple of years. In 2021 alone, there were record-breaking #heatwaves , a #winterstorm that shut down cities across #Texas, multiple #hurricanes, record-breaking #wildfires, #tornadoes and #hail storms. All of which damaged public and private property and harmed people across the country.

"Part of preparing for even more extreme weather to come as a result of the #ClimateCrisis, is investing in resilient #infrastructure–something the current administration has already proposed. While building infrastructure may sound like a feat fit for futuristic technology, around the world climate-proofing has been happening already for centuries in the form of vernacular architecture. This form of architecture is defined by the use of traditional materials native to that particular region.

"According to a report in Oxford Urbanists, there is a possibility of a resurgence of vernacular architecture. Otherwise known as traditional, cultural design methods unique to a particular region, vernacular architecture is an alternative to the 'international style' of Eurocentric homes that took off globally after the first world war. Throughout the 20th century, 'identical skyscrapers, airports, malls and gas stations became icons of modern cities,' the report points out. However, those structures are not always made with climate change in mind, and don’t rely on locally sourced materials or local #cultural knowledge. Those homes were not made for the entire world’s diverse array of weather events like hurricanes, wildfires and tornadoes. Drawing on vernacular architecture could be a way of making our cities more resilient to an ever-changing climate.

"A well-known example of cultural and regional identity through vernacular architecture is #Pueblo architecture. The permanent, attached homes modeled after the cliff dwellings built by the Ancestral Pueblo (#Anasazi) culture first appeared around the year 1150 AD continue to be used by Pueblo peoples today. A common revival of the style called Santa Fe style, a mix of Pueblo architecture and Spanish colonial architecture, can be found in southwestern states like #Arizona and #NewMexico. Pueblo inspired homes that used dried mud often constructed with locally sourced materials. The thick mud walls are great insulation for both extreme heat and are made to protect residents from especially hot days and from cool desert nights.

"Across similarly sweltering Southern US states, vernacular architecture in the form of shotgun houses feature high ceilings for heat to rise up to, doors that are aligned to improve circulation into the home without costly AC bills.

"In some of the most heat-impacted places on the planet, #vernacular architecture is already being used worldwide in response to climate issues. Architects and designers are not just turning to local materials, they’re turning to #historical design to work around energy needs. Traditional #Arabian techniques like #mashrabiya have been incorporated into iconic modern buildings in Abu Dhabi, a city in one of the most heat-threatened countries in the world. Architects in #Morocco, which is especially vulnerable to climate change, have incorporated vernacular design, like large north-facing windows and smaller south-facing windows to bring in natural light while maximizing air flow for natural cooling and ventilation in public buildings like schools.

"'We wanted to retrieve a sense of heritage, but in a modern way,' Moroccan architect Driss Kettani told CNN. 'We tried to use the same (energy-efficient) solutions found in the small earthen towns in the south of Morocco.'

"These techniques can be used anywhere, even areas of the world with less-obvious climate impacts. Chris Lawson, the managing director at UK-based design firm CK Architectural says that the firm has worked in the #Cotswolds area, which is filled with towns that can source their own building materials. Woods used in the homes can come from local #trees that are already adapted for the English weather, which makes them an ideal building material. Builders are able to excavate the local limestone they need to build homes, a climate-friendly alternative to materials that often have to be transported from elsewhere and weren’t built to withstand the local weather.

"'It was incredibly strong, easy to find, a solid insulator from the Great British weather, and environmentally friendly due to no transportation requirements too,' he explains. 'This can be done across the whole world too.'"

Source:
https://getpocket.com/explore/item/ancient-architecture-might-be-key-to-creating-climate-resilient-buildings?utm_source=pocket-newtab

#SolarPunkSunday #SolarPunk #AncientTechnologies #Vernacular #AncientArchitecture #BuildForClimateChange