Bamboo

Articles Tagged with: Bamboo

18 December, 2011

Introduction

It is the biggest grass in the world, it is the food of panda, and the shoots taste really nice in stir-fry. This was really all I knew about bamboo before coming to Sabah. Well, working with Arkitrek changed that, particularly through working on the Lupa Masa project. I am fascinated by the fast growth rate, negligible embodied energy, and extensive applications. In many instances it can be a viable substitute for hardwoods. When striving to build with minimal environmental impact it is the wonder material!

Genus of bamboo

Current estimate is that there are 49- 59 genus of bamboo in the world, between 800 and 1000 species, growing between 46°N and 47°S, in altitudes of up to 4000m. In Sabah, there are 35 known species of 10 different genus. Many of these are still lacking in research and one is still unnamed.

Harvesting

For construction, bamboos are deemed mature between 3- 5 years, or when there are white spots on it. For craft applications young bamboo is often needed. Bamboo should be cut during the dry season, so that there is less moisture in it. Folk law dictates that bamboo should be harvested around the full moon, 3 days before at the earliest and 3 days after at the latest. Apparently this is a widely held practice, with consensus not only from Sabah but also Costa Rica, Columbia and Indonesia.

Is this just common myth, or is there scientific basis for this belief?
It is thought that the full moon draws the moisture and starch from the bamboo, therefore without starch to feed on, bugs do not lay their eggs in the bamboo. The gravitational pull of the moon is strong enough to create tides – is it strong enough to make such a difference to the starch levels in bamboo? This theory is often contended.

Preserving

Irrespective of harvesting time, bamboo must still be treated against wood boring insects and fungus. Again many local methods exist. Standing it against a tree, raising it out of contact with the ground and leaving it to dry for 4 weeks is often done. It is said that the skins of salak fruit can be rubbed on the bamboo to preserve it, or that the bamboo can be soaked in a concoction of natural materials, including Neem leaves.

In Sabah, the method of soaking it in a muddy puddle for two weeks is practiced. More commercially the bamboo is treated with Boron, a chemical element.

In Nepal, The Adobe and Bamboo Research Institute (ABARI) has developed a means of pressure pumping the bamboo with borax. It is a fast and effective method. The Institute is currently testing a Neem compound as well as cow urine, which is used in Napal as a preservative for timber. http://abari.org/treatment

Construction

In Sabah, ‘Poring’ bamboo (Gigantochloa levis) is the most suitable for construction. As its scientific name suggests it has a large cross section. Buluh betung (Dendrocalamus asper) is also noted as being strong and durable and good for construction, although it is difficult to find in Sabah (there is a record from Long-Pasia by Tony Lamb). Tamalang or Tambalang (Bambuso vulgaris) is another common species and is often used for building bridges or masts for boats etc. some other species in Sabah are mostly used either as external facades, split for flooring or used in basketry and mat weaving, or used for utilitarian purposes such as cups and drinking straws for tapai (rice wine).

Nails are unsuitable for construction as they split the bamboo. At the Green School connections are made by carefully drilling the bamboo and bolting it together. This is necessary as the buildings are at such a large scale. In our small sulaps at Lupa Masa we used the tradition method of bamboo pegs and rattan ties. The rattan details are little moments of crafted beauty, thanks entirely to craftsman Lassius and his father!

While Poring bamboo is a good construction material, and has proved successful at Lupa Masa, it would be interesting to experiment with using species with thinner culms, but using them in groups of 2-4 sections to spread the forces. It would give an elegant finish and would develop a system that cold be used in areas of Sabah where there is less Poring bamboo to be found.

Forms with bamboo

Sadly the Poring bamboo is not easy to bend. It tends to snap and splinter making the organic forms of Indonesian bamboo buildings hard to achieve. However, it is not impossible. Over time, the bamboo’s own dead weight can induce gently curved forms. It might also be possible to bend it slowly over the two weeks that the bamboo is being treated by the ‘muddy puddle’ technique. The most ingenious solution found yet is at the Green School in Bali, where the sweeping curves of the classroom roofs are created, not by solid bamboo sections, but of very thin long sections that are bound tightly. In such a fashion, beams are created.

Facades and surface finishes

Bamboo can be worked in whole sections or in split sections to create a variety of floors, wall fills and partitions. Our kindergarten on Mantanani will be an exciting development of the bamboo rice basket as a facade.

Future of bamboo

At the Green School, neighboring farmers plant bamboo around their rice paddy and have a guaranteed market for it once it has matured. It not only gives an additional income to the farmers, but it also guarantees a supply of bamboo to the school.

In Sabah, there is potential for a similar community growing and harvesting enterprise, coupled to a treatment and training center. There is already a growing interest and even a market for treated bamboo in Sabah. However, in our attempts to work with bamboo we have faced some amusement from local builders and in some cases, a fair amount of resistance. We were told that the bamboo had run out which was mysterious as we were still able to see it growing wherever we went. After some months of persistence we realised the truth: nobody could be bothered to go and harvest it. This wasn’t a question of price because we were being offered hand sawn timber from the same forest for much cheaper. Surely bamboo is easier to harvest and lighter to carry than timber? (not to mention more sustainable)

With bamboo receiving much more hype in green building circles, it is inevitable that someone will step in and sort out the supply chain. Now is the time for an enterprising community to step forward and do it, before outside companies take another resource away from the local people.

Case Study

The photos below are from the Green School, Bali; an inspirational place not only in terms of it’s bamboo architecture.

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21 January, 2011

Reclaimed Timber

By Ian Hall

The row of dark brown circles on the timber in the photo above are where bolts used to hold together the structure of an industrial warehouse (below). Responsible specification of timber in building projects gives me a headache. Reclaimed timber seems to be one of the best options but it’s hardly a solution to the mass market. What’s more, it may cost more than freshly cut timber so why should architects specify it?

Most of the timber that we used in the recent renovation of the Main Lodge building at Borneo Rainforest Lodge came from this warehouse. When specifying timber architects should consider the source. The lodge may contribute to the conservation of it’s own patch of rainforest but it wouldn’t be helpful for the building to cause rainforest loss elsewhere.

The advantage of specifying reclaimed timber is primarily to reduce demand for virgin timber. Another advantage is that timber is effectively a carbon store until it is burned or composted. Finally, reclaimed timber is invariably well seasoned which means that it is more reliable to work with and has an attractive appearance. As in the accompanying photos, the appearance can also tell a story about its past life and this appeals to the sentimental amongst us.

The downside is that the vagaries of supply effectively rules reclaimed timber out of the mass construction market. Even in smaller projects the added cost may deter some clients. Virgin timber is cheap because we don’t often pay the full environmental cost of timber extraction. This might include habitat restoration after logging and measures to reduce soil loss during logging for example. Reclaimed timber by comparison can be expensive due to it’s scarcity together with the labour cost of reclamation, cleaning and sorting.

The most viable alternative for a quick solution is to specify timber certified as sustainable by an organisation such as the Forest Stewardship Council. This however comes with no guarantee that you won’t cause damage to a valuable natural resource. The best FSC can do for you is to promise that using FSC certified timber is better than doing nothing.

There are no easy answers. We should try to use reclaimed timber where possible, use alternatives such as bamboo and coconut palm where practical and if we really must use virgin timber, try to make the most informed decision about where it comes from.

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4 December, 2010

Rungus on Top

This is our proposal for a community kindergarten at Kg Tinagol in the North of Sabah. It will be built by staff and volunteers from Camp Tinangol, a community tourism program operated by the locals with support from Camps International.

There are a number of innovations in the construction which respond to sustainable design questions.

Design by: Ian Hall, Eoghan Hoare and Oliver Wilson
All Images by Oliver Wilson

The community’s brief was for a three classroom kindergarten on the bottom and a community hall on the top. Our design response was to propose a first floor based on a traditional Rungus Longhouse and a ground floor using biocomposite concrete. Man, our project coordinator from Tinangol took great delight in this and confided to me with a snigger “Rungus di atas, style orang putih di bawah – lain daripada biasa” or; It makes a change to see Rungus on top!

Using biocomposite concrete – in this case mixing sand, cement, lime and rice husk – we reduce demand for cement and aggregate and create a building envelope with better thermal performance than the normal brick and concrete used in these parts. Rice husk is available in the village out the back from the communal rice thresher.

Coconut posts are also available locally and by using these for the ground floor structure we avoid using Ironwood which is the timber of choice but now locally extinct.

Replacing ironwood with coconut has it’s challenges because unlike ironwood, coconut will not last for 30 years. In fact we will be lucky to get 10 years and it should not be used at all for foundation stumps. Our reponse to this was to develop a concrete plinth to raise the coconut above the ground and attach the posts with steel brackets and triangulate them with steel cables.

Our design exposes all of the coconut posts so that their condition can be monitored throughout the building’s life. The bolted connections allow posts to be replaced as required.

All of the necessary construction techniques required to build this kindergarten are familiar to the locals – steel cables on the ubiquitous suspension bridges for example or homemade concrete blocks. Our challenge is to adapt existing technologies and materials which may have been overlooked by the weight of conventional wisdom.

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19 October, 2010

Lupa Masa

The name for our jungle camp came after a few bottles of wine. Reclining on siliu bamboo floor under a sheet of tarpaulin we bandied ideas around. It had to be something marketable, a brand that would not be confused with any of a dozen other nature lodges, jungle resorts, rainforest lodges, river lodges, wildlife resorts etc etc that can be found in Sabah.

Lupa Masa means ‘forget time’ and Lupa Masa time, such as it is, is set an hour later than standard Malaysia time. Who likes to get up at 6am to go birdwatching when you could get up at 7am? Confused? why not just forget about time and get up when it gets light, rest when it gets hot and bathe in the cool evening when the six-o-clock cicada starts to call.

The six-o-clock, or emperor cicada has it right. He starts singing when it gets dusky. This is earlier on a gloomy day than a clear day. Sometimes he gets confused and wakes up briefly in the middle of the night, which is also fine, the indian cuckoo does the same thing.

Visitors not used to the jungle may find the first night disturbing. By the second or third night however the jungle sounds become soothing. You may not be able to tell the difference between a frog, a cicada and an indian cuckoo but you can give your own names to their calls as they become familiar.

The sleeping quarters at Lupa Masa are stretcher hammocks in bamboo sulaps. The floors and walls are bamboo and the foofs are palm thatch. Sulap is a local word for a temporary structure, usually a rice barn standing in a paddy field or a temporary home in the field during harvest time.

Work started on our sulaps about 4 weeks ago and we’re about ready to put the roofs on. The contractors are all local fellas, not actually a contractor but rather a team of skilled guys who are also farmers, jungle guides and hunters. We’ve been enjoying the design process. Or rather, we’ve been enjoying making it up as we go along.

The architectural detailing was not prescriptive but adaptive. That’s how we’ve ended up with various patterns of rattan bound joints, bamboo slats and siliu bamboo floors. Siliu is the local name for a technique used all over Asia of splitting bamboo lengthways with multiple overlapping parang cuts and opening it out to form a flat flooring or cladding material.

Next phase of construction will be the restaurant and shower block. Having made a good start in building trust with our builders we’re going to stretch them a bit on this one. Up until now we’ve been doing all the bills of quantities, purchasing and delivery ourselves. Now it’s over to the villagers to take on some more responsibility.

The materials delivery in particular is tricky because everything has to be carried in by hand. By involving the builders in the design process they take some ownership of design decisions. In practical terms these decisions involve trying to use bamboo framing and random rubble stone walls as much as possible. Bamboo can be harvested near the site and plenty of stone has been dug up in our foundation work and more is available in the river. Concrete is the killer as both sand and cement has to be carried in.

This collaborative approach makes sense because each decision has an implication for how much material to carry in. If the person doing the carrying knows that every effort has been made to reduce the weight of materials then they’re likely to be a little happier about doing the carrying – If you can ever be happy about carrying a 50kg bag of cement.

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13 September, 2009

Kampung Details

Here is a selection of quirky architectural details found on a project site at Kampung Tinangol Sabah. Kampung means village in Malay and is synonymous with things improvised, honest, basic and hardworking, to use just a few adjectives.

The long house. Note that many posts are wonky. I learned recently that bent posts serve as rudimentary braces in lieu of triangulation, thus keeping the structure more stable.

The long house veranda is popular for the afternoon snooze, presumably because the slatted bamboo floor feels cool in the hottest part of the day. At night the porch is the preferred space due to the multi-tiered seating options that facilitate a more convivial atmosphere. Traditionally long houses do not have a porch and this modification was made with westerners in mind who are not used to socialising while sitting on the floor.

Bamboo reinforced concrete. The single steel bar is a beam while the rest of the worktop is reinforced with strips of green bamboo. What a great idea, I can’t wait to specify it.

The troweled splodge plaster finish.

Bamboo bench from the notchit-and-botchit school of detailing. Temporary bamboo shelters abound in rice fields and front yards throughout Sabah. Lore dictates that for maximum durability you harvest your bamboo on a moonlit night and then soak it in a ditch for a week or two to drive out the wood-boring insects

I simply like the shape of this barn, that’s all.

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