Bali’s 'magic' bamboo homes [video] | Hacker News Reader

Bali’s 'magic' bamboo homes [video]

bbc.com

129 pointspseudolus78 comments

It's an amazing building material and there have been a number of recent articles that have highlighted its use as scaffolding material that can be built up to several hundred feet high.

https://www.dailymail.co.uk/news/article-2290166/Hong-Kongs-...

In regards to very tall bamboo scaffolding...

A related side topic here might include near famous Indonesian disregard for safety - or at least willingness to overlook it. One of the reasons I was told that by Indonesian workers in Malaysia, whom there are many of. They’re willing to work cheaper and do more dangerous jobs.

KL in particular has a ton of skyscraper work being done by Indonesians and I saw first hand the lack of what i would consider appropriate safety.

I’ve been told by Indonesians their style is to dive head first into the water, then check for rocks. Yes safety is a big issue there and causes a huge amount of needless suffering.

If there is one thing spending time in SE Asia has taught me is that the value of human life is just different in some places.

Good or bad, from scooters to skyscrapers. It’s just different.

Yes life is cheap there, people get sick, injured and die for preventable reasons all the time. Life expectancy is 10 - 15 years less than in developed countries as a result. The west I think mixes up politics with their world view which makes them think everything is equal somehow, it’s then surprising when they see such foolishness that leads to such suffering first hand.

I think causality goes the other way.

When life expectancy is low and you may die at any time for all sorts of reasons, it is rational to take a lot more risks than if you'll very likely live past 80.

Having been in SE Asia and Bali many times and seen how they spray chemicals against insects... I wonder how they handle that in the middle of the forest... I would never go there without an independant assessment... I love the design but I prefer something closed and airconditionned (mosquitos). Mosquitos are a major issue (even in cities): https://www.nea.gov.sg/our-services/pest-control/mosquito-co...

I agree...it’s beautiful and makes you get a real sense of the nature that surrounds you but from a practical and being widely used perspective there are a lot more problems to be solved.

Trash. That was the craziest thing to see in Indonesia. There is just so little trash service that dumping it behind your house and burning it now and then is just how it is. Which if it was just Bali might be overlookable but Indonesia is the close to population of the entire USA.

As an Indian - yeah Mosquitos are a real problem in SE Asia. The usual techniques of dealing with them are - use mosquito nets. In a different video the owners have a mosquito net on the bed frame. Usually with mosquito net, they are a non-issue during night time. The hard to deal with problem is evening time.

The truth is - these houses will never be as comfortable as a centrally air conditioned houses of US. Evening problem can be somewhat dealt with blinds and nets that close off the house after sunset. But the best method is, usually to turn-in early to bed. That is what, people who live in villages do. In the end - owners have to adapt and I do not think these houses are for everyone.

This is a valid critique of the design of that particular building, but not of bamboo as a building material.

Having seen amazing bamboo scaffoldings in HK. I have no doubt about building material (minus how do they treat it against insects health-safely).

Mosquitos in Bali seem to be more of a problem inland (eg Ubud for tourists) than on the coast where most of the resorts are.

This video made by CBS has a few more details, including air conditioning: https://youtu.be/tPJbtMuZvbU?t=196

One problem with bamboo is that it easily grows mold. So even if you treat the outside it's entirely possible mold is growing on the inside. I'm sure there are some good ways to "dip" bamboo and coat it in something to prevent mold growth. I live in Hawaii and I won't use anything with bamboo because it always seems to eventually mold.

To be fair, Hawaii is a pretty extreme environment for mold problems. Bali likely is too, but it's hardly fair to judge the material for mold problems when hollow PVC will develop mold too...

PVC actually does pretty well against mold growth. It's the organic materials that are usually the biggest problem. Metals, glass, and dense plastics are fairly mold resistant.

I visited this bamboo factory and village. I forget exactly what chemicals they used. I think they said it was a 'bromine bath' - they have long troughs that they fill with bamboo, then pump full of warm liquid. They let them soak for an amount of hours, then wash off the solution. They said this process both hardens the material and makes it less vulnerable to pest damage. Bamboo requires different amounts of treatment for different uses (sounds like too long makes it brittle, but very hard).

Didn't see a spot of mold on the houses we toured - but I'm certainly curious about the longevity as well.

Another neat design trick: they would cut little square holes in posts about 3 feet off the ground, so they could pour the supporting footings through the hole so the cement actually extends a few feet up into the post.

Here's their website - if you're in Ubud, you should visit! Their ~1-2 hour walking tour was nice. Or, you can book ahead to stay in one of these houses. http://greenvillagebali.com/

This is good design thinking and implementation. My only question would be the susceptibility to fire, any thoughts on this?

Bamboo doesn’t burn well. Often used for cooking because you can throw it in the fire letting food cook inside it. I really liked native dishes that had bamboo cooked chicken.

Design thinking is one of the worst things that came out of IBM. It is an appalling jargon of shaky abstract ideas that, when the time comes to implement, fall apart and at that point you're just doing what any intelligent person would do - use logical reasoning, observation and rational decision making that would occur anyways without this Design Thinking bullshit. This stuff [1] bothers me to no end - Can someone tell me what the hell is this [1] guy talking about!?

[1] https://www.youtube.com/watch?v=psLjEBUOnVs

Since bamboo is hollow could filling the bamboo with concrete be used to reinforce and increase its load bearing strength?

My guess is no. Concrete fails under tension and with the irregular and natural assembly process the structure probably would have issues with tension and all the extra weight. The cost of filling each bamboo void would also make it costly and less renewable. My gut feeling.

Maybe, but the real reason you don’t fill bamboo isn’t entirely hollow. It’s just got individual hollow segments.

Bamboo is already incredibly strong as it is. The main concerns seem not to be about bamboo’s strength, but rather it’s susceptibility to insect attacks.

They look nice, but I can’t help question how safe they really are, they’re more like giant baskets woven together by artists as opposed to calcuated engineering by engineers.

Can you explain how this is not "calculated engineering by engineers"? My impression from the video is that these are architects and engineers building these.

It's very similar to the work of Shigeru Ban who has done a lot of work with paper tubes and timber. Some of his work is visually spectacular. There are some photos on his wikipedia profile.

https://en.wikipedia.org/wiki/Shigeru_Ban

It’s Indonesia, engineer doesn’t really mean what we think in the west. It’s more that someone is passionate about something, not that they have a civil engineering degree and are building to some code. There are engineers like we’d think in Indonesia of course, but they’re unlikely to work on a western lady’s pet project and are going to be a lot more expensive.

So more like a software "engineer" ?

Sort of, but if the software engineer had never had access to CS material and worked in a company where practices were based in CS so they naturally picked it up. These are villagers that build small homes without machinery and very basic tools, and haven’t learned from experts.

The particular style of the house in the video is just one many possible designs. I’m sure there’s nothing to stop one from using bamboo in a more calculated design.

I am more interested in the engineering aspects of Bamboo than just the aesthetics. The entire video is about how unique it is, and how beautiful it looks. None of that matters if the whole house of cards falls over. There was an interesting brief comment about treatment to protect the Bamboo from rotting away but very little information was conveyed in the presentation. I wish they'd show the technical fundamentals of why Bamboo is unique.

Bamboo has a very good strength to weight ratio allowing you to build very tall structures. The real issue is it degrades faster than wood.

I visited this bamboo factory - they soak the bamboo in a chemical bath (bromine I think?) and wash it off to make the bamboo harder and less vulnerable to pests.

As such, the bamboo they are building with may have notably different mechanical properties than raw, dried bamboo.

I have done some bamboo construction here in Thailand. In addition to mold problems, untreated bamboo gets eaten by powder post beetles. Treating the bamboo with a borax/boric acid solution preserves it for many years and does not affect its strength. I have bamboo rafters on a cottage that are still solid after more than 10 years. A few untreated pieces at the edges were eaten up in 3 years.

The way I did the treatment was to use a long piece of sharpened rebar to punch out the membrane between the sections in the bamboo poles, leaving the last one intact. Then stand the poles vertically and pour in the solution and let it soak for several days. So I did not need a tank to soak them in. Also, soaking them in a tank is not very effective because the outer skin of the bamboo poles is pretty water proof so the solution doesn't soak into the walls which contain all the sugar that the power post beetles crave. After treatment you let them dry thoroughly and then they are ready for use.

You need to protect the treated bamboo from the weather since the chemicals are water soluble so the ends and any cracks will allow rain to leech it out and expose it to attack by fungus and pests. Also not suitable for direct contact with the ground for the same reason.

Other treatment methods I have seen that are aimed at converting the sugar to make the bamboo unattractive to pests: Roast the poles over a low fire - results in loss of strength. Soak them in a running stream for a few weaks - results in a very foul smell that takes a long time to go away.

Bamboo construction is very interesting but there are some real challenges with making good connections with it. It has great tensile strength which all comes from the skin of the bamboo. Putting holes in it, nails, screws, bolts cause the bamboo to split, making it difficult to take advantage of its tensile strength. Connections that grab the outer circumference make the most of the tensile strength but due to the high dimensional variance of bamboo nearly every connection ends up being custom made.

And what effect do those chemicals have beyond just making bamboo fair the elements better ?

If its anything like pressure treated wood in the us I would not go anywhere near it.

Also. Who funds this? This sort of looks like a rich persons pet project that won't go anywhere. It looks alor like I am busy saving the world sort of projects that maybe help a hand full of people untill somebody gets bord.

It's just treated with borates. Wouldn't use it in wet locations or for direct ground contact because it's water soluble and that would hinder its protection, but it's far from toxic as you seem to be implying.

Meh, even if it was some random pet project, it's not the worst way for them to spend their money / time.

Every bamboo pole is different.. For this reason bamboo could never fit into modern engineering practices. Engineers use things like I-beams because, (in theory) each one is the same and they have been tested (probably millions of times) Their structural characteristics are known. So an engineer can sign off on a building and the team can get architectural indemnity insurance. Bamboo, and also things like using the entire trunk of young trees, are much much more efficient in terms of embodied energy. Eg, a tree is designed for strength / flexibility, why cut it up and then glue it back together to form a gluelam beam? Its because engineers can sign off on it then..

Maybe theres some innovative way to integrate stuff like bamboo into modern engineering practices, maybe each individual unique bamboo pole could be scanned (like an MRI) and AI could be used to accurately structurally model it. The the whole structure could be accurately modeled and signed off on in theory.

Don't we deal with the variability of natural products in lots of places by grading? This example is not structural, but every piece of beef has a USDA grade.

I think it is a matter of coming up with a standard (maybe it is imaging each piece of bamboo) means of categorizing the qualities of concern, and then selling in grades. Each grade would indicate a minimum quality or set of qualities.

Structural engineers are weird. They want to be able to guarantee that a structure can withstand a certain load. Eg. They'll calculate the maximum load the floors will take (eg. if its an office and filled with filing cabinets) and then multiply that by a safety factor of 10 and design the structure to support that, at the very least. They'll probably make it even stronger so the structure never even flexes (which is not unsafe but it can just unsettle people)

The goal is, it is impossible for this structure to fail under any likely conditions, so eg. any kind of wind load thats been experienced in so many decades.

We do this with dimension lumber. There are a couple of different processes of assessing the strength of a piece of lumber, but the designation is MSR (Machine Stress Rated) "is intended for any engineered application where low variability in strength and stiffness properties is primary product consideration" (1).

It looks like there have been attempts to do the same thing with bamboo, starting with adapting existing lumber grading machinery (2)

I don't see why it would be impossible to use bamboo in engineering applications as long as the physical properties of a given grade of bamboo stock could be guaranteed.

I assume treatment for pests, rot and fungus would also need to be applied to guarantee that those properties remain inviolate, but am no expert on bamboo.

(1) - https://www.wwpa.org/western-lumber/structural-lumber/machin...

(2) - https://www.researchgate.net/publication/313531323_Grading_o...

How is this incompatible with a product that comes with minimum guarantees?

Say we have a way to grade bamboo (this is the question mark in my argument). Grade X bamboo would support the floor in question. Grade 10X bamboo would support 10x the floor in question. For the floor in question, use Grade 10x bamboo.

I mean, it seems like something similar must be going on in structural lumber. Take 2x4s for example. This is one piece of wood out of a tree. There must be natural variation across the population of trees providing wood for these. How do we handle that except by saying that this piece of lumber meets minimum guarantees but may be stronger than that minimum, and is statistically likely to exceed the minimum.

Houses in the US are usually built with wood beams that are very variable in structural characteristics. Whole bamboo is probably more variable, but this isn't an insurmountable problem.

Wooden planks actually do regularly come with knots and large differences in strength due to the grain - we are able to work around this due to familliarity with them at all parts of the supply chain.

As for why we use planks and not logs? They're all the same size - A lot easier to transport and use.

yeah but timbers like that are very unlikely to be used structurally anywhere outside of small domestic scale construction.

I saw articles about cutting bamboo poles into blades~ (for lack of a better term) to be joined later to form regular blocks. Less simple but easier at scale.

Can bamboo be processed into regular rectangular shapes? Would be cool to see bamboo 2x4s. The specialization required to handle unique bamboo canes and the design constraints of its shape seems like it would cancel out its cost savings.

Wow, those are beautiful. Very organic feeling. I wonder how much those structures cost...

500k USD for that magnificent 6-storey building, according to this video: https://youtu.be/tPJbtMuZvbU?t=196

I'd need to see an independent assessment of the structural integrity of this type of ideas, especially if it was designed and built in Indonesia.

Even if it was assessed independently, I still would not feel safe because the engineering scrutiny and structural discipline was perhaps not an integral part of the development process. I just have a hard time trusting novel civil engineering projects without insane amounts of engineering data.

Cant even get a crack shack in SF for that.

What kind of treatment are they talking about?

I believe they treat the bamboo with a borax solution. The designer gave a TED talk that goes into more depth.

https://www.ted.com/talks/elora_hardy_magical_houses_made_of... (treatment method is mentioned at: 4:08 into talk).

Pretty cool, though Bali's climate helps.

What's it like? Also, won't you get insects and birds everywhere with open spaces like that?

It's more humid than straight up 'hot'. And when it rains, it pours like there's no tomorrow; rainy season, anyway.

I was staying in a medium-sized house in a fairly tucked away village; surrounded by jungle and rice fields. Over the 3 months that I stayed in this house, I saw iguanas the size of my arm, several snakes cruising in the backyard, and plenty of ants that like to eat bamboo and other wood-stuff.

That being said, most birds stay away from people and is uncommon for them to just chill in these open spaces. As for insects, it's not THAT big of an issue.

Sometimes there are these little bugs that fly into houses with lights on, right before it starts to rain -- these can be super annoying.

Everything else is manageable. Some 'businesses' like to use chemical sprays around the area to avoid having mosquitoes and such fly inside. But the use of chemicals isn't entirely environment-friendly and can make plants die off pretty quickly.

Locals don't use chemicals in their own homes and is simply a 'luxury' that Westerners have both imposed and expect from certain places.

I found the coil burners to work pretty well for mosquitos, although I have concerns about how healthy they are. I guess if I lived somewhere like this I'd just get used to it - although mosquitos in Europe seem to be getting stronger every year, so I guess that won't take long.

A lot of people seem to like the Lemongrass repellent, both in liquid and candle form. And there's locally purchasable incense (organic) that will keep mozzies away, too.

The coil works really well, but I resonate with your sentiment on coil's health effects.

I've always wondered why there aren't lasers which can shoot down mosquitoes on its own.

There is a company working on it… https://en.m.wikipedia.org/wiki/Mosquito_laser

The current plan is a ‘fence’ which will detect, identify, and kill 50 mosquitos per second. It can be tuned to only kill female mosquitos of the malaria carrying species measuring reflectivity and wing beat frequency. They speculate it could cost $50 for a 30 meter fence.

Looks like the company is targeting citrus pests in order to get some cash moving, mosquitos will come later now. https://www.technologyreview.com/s/603721/insect-zapping-las...

Their commercial site: https://photonicsentry.com/

Why on earth would you target only female mosquitos!? The males are rare and required to make more females. Seems like you would want to blast away with indifference.

Yes, I am aware the females bite. Males are much more rare, is the goal individual death or is it population control?

I believe only female mosquitoes bite humans.

http://www.cmcd.org/biology-2/mosquito-myths-facts/

Because females are the ones that bite and transmit malaria.

https://www.cdc.gov/malaria/about/biology/mosquitoes/index.h...

Killing the males is pointless if your goal is preventing disease.

The climate is pretty much always tropical and warm though often rainy. Those kind of open spaces work well as living areas though most people sleep in more conventional closed rooms, often with aircon for the better off. The places I was in with that kid of construction used it for restaurant / reception stuff with people sleeping in regular concrete structures.

I wanted to make a bamboo cabin or even house.. This could come at a better time.

I'd need some walls in my climate here though.

It's what year now, and the video is still Flash?

Density of Carbon Fiber is 1743kg/m^3 and that of Bamboo is 1160 kg/m^3.

Acrlyic, Nylon, Polycarbonate have similar density as Bamboo.

Bamboo's strength falls somewhere between fiberglass and carbon fiber

Some things to think about include ecological factors (bamboo is renewable), environmental factors (bamboo is flammable), loading factors (steel can be made ductile and its high properties are isotropic), and weight considerations (bamboo is much less dense) compared to Steel.

> bamboo is renewable

What if it's treated?

I think the parent is referring to being able to grow easily. Per the video, an 18m timber can be grown in 3 years.

I believe you are thinking of recycle-abiliy, which would be reusing an existing piece of bamboo.

Both are valuable considerations.

Is this density including the void inside, or just for the non-hollow parts?

Excluding void.

For a long time i am looking for a synthetic bamboo equivalent for acoustic properties.

But so far I've not found anything similar. I am thinking, what if I engrave bamboo like pattern on carbon fiber, will it produce similar acoustic?

Can any material/sound/chem engineer help me?

I've worked with both materials, although not in acoustics; I don't think they'll ever sound alike. CF sounds "light" compared to bamboo, when thin, and dull when thick.

I think carbon fiber instruments sound interesting, just not a match for bamboo.

There would be the issue of cost when replicating the thickness of bamboo as well, I'd imagine?

Density of CF is 1743kg/m^3 and that of bamboo is 1160 kg/m^3.

Acrlyic, Nylon, Polycarbonate have similar density as Bamboo.

https://newt.phys.unsw.edu.au/music/people/publications/Flet...

> looking for a synthetic bamboo

Just curious, why?

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