Your local material in construction
Reluctance to use bamboo is rooted in the absence of design standards and unpredictable performances.
Where do we source design ideas from? Today it is common to check the internet, books and may be a few buildings around us, generally creating buildings with a modern appearance.
Countering these trends, though occasionally, we get to see newly built traditional structures. They are contemporary, yet are traditional as a cultural expression. In many ways they perform better, functionally and climatically. The Nagaland style tourist facility under construction at Puri beach is a proof for both.
Naga bamboo is straighter than the local, besides being stronger thanks to its thicker outer shell and smaller central hole. It has nodes at shorter intervals with strong diaphragms. These average 5-inch diameter culms are being used for all structural purposes, while the rest of non-load bearing members are from Orissa itself.
Selection of bamboo is the most important, with every culm treated to reduce sap content. Lengths with signs of cracks are used for slicing and splitting, Split bamboo is commonly used as walling material, weaving it between the vertical bamboo frame to gain strength and reduce porosity.
Subsequently, mud mixed with hay or grass, stabilised soil cement mix or regular mortar can be applied on the surface. This kind of walling is also called as wattle and daub method.
The floor base has to take live and dead loads, so it is made of thin bamboos laid in close proximity with floor joist members, at 2 feet spacing. The final floor finish could be with mud grass mix topped with cow dung, wooden planks, cement oxides or even layer of local thin stones. The ceiling too may have the interwoven split bamboo appearance, but factory finished bamboo matts are now available as a ceiling finish.
Roofing is among the more critical decisions in bamboo architecture. While the support system could be same as for floor, the final roof has to be appropriate.
Due to the possible unevenness of bamboo, direct placement of interlocking Mangalore tile is difficult.
So, thatch, metal sheets, ferro-cement and such others can be tried. It’s better to keep the roof angle steep, for both structural stability and faster rain runoff. In Puri, they are using local paddy straw which has shorter life, but it’s economical and easily replaceable.
Being wider at the base and thin at the top, round bamboo can be tricky in achieving uniform sizes and well secured joints. It is vulnerable to cracking and splitting, which of course, can be managed by experts. They would also know how to avoid getting harmed by split edges, sharp tips, peeling of skin and such others.
However, professional reluctance in using bamboo does not come from issues like the above. It is rooted in the absence of design standards and unpredictable performances, dependent upon species and location. But if we see how bamboo has lived with us for generations, it’s our duty to give it due regard.