Construction process of Bamboo houses

Construction process:-

 Introduction:-

Only basic carpentry, masonry tools and skills are necessary for the construction of bamboo house. The following methods are recommended for working of bamboo poles:

Cutting with machete knife. Splitting the pole in half by using machete knife Splitting the bamboo culms into four or eight segments using a knife frame Peeling of the bamboo, when the age is less than 18 months. The strips can be used as ties or can be woven together to make strings or ropes Bending - freshly cut bamboo can be bent. If heated at 150oC the bamboo keeps its shape after it goes cold. Foundations and plinth course:- Bamboo canes should not be exposed to moisture. This is the main reason for which using bamboo in foundations is not a good practice. Bamboo canes should not touch the soil since their durability is greatly affected. Concrete foundations are recommended for greater stability. Concrete wall bases prevent humidity affecting the bamboo canes in the walls. A trench of min depth 0.5 m and min width of 0.3 m is excavated. The trench can be filled with field stones and cement grout in layers to form strip foundations underneath walls. It is recommended that the plinth course be completed also in concrete. The height of plinth should be above the flood water line or a minimum of 350 mm above ground level. Therefore formwork should be erected for the plinth course to be constructed together with the foundations. The bamboo columns should be erected in place and be embedded in the plinth course min 250 mm. The canes should be attached to the formwork to ensure vertical position during concrete casting. The following specifications can be used: Field stone - max size 200 mm Grout - cement based mixed in proportion 1 : 4 (cement : sand) by volume Bamboo columns - canes with diameter of 100mm Concrete for plinth - mix by volume, cement : sand : aggregate : water = 1 : 3 : 3 : 1.3.

Construction of walls:-

The walls are constructed between the vertical bamboo columns, as infills. The main posts are erected at all corners, and throughout the house envelope, spaced at about 1.2 m. Split bamboo grids are assembled by rope or wire ties and are fixed to plinth and bamboo posts. To reinforce the bamboo grids, as well as to provide a base for the mortar, a chicken steel wire mesh is fixed to the grids. Cement based mortar is then plastered on top to provide overall stability to the wall infills. The finished wall thickness is about 50 mm thick. Prefabricated timber frames are mounted for windows and door openings.

Construction of top timber plate acting like a bond beam:-

All bamboo columns should be fixed to a top ring continuous beam. This member should be made from timber and should have rectangular cross section. Bamboo poles should not be used for top ring beams. This beam acts like a bond beam, providing restraint and stiffness to the bamboo columns and walls. Care should be taken to ensure continuity at wall corners.

Construction of roof:-

The roof should be ideally as light as possible. This would not only reduce lateral seismic loads, but would also reduce the risk of casualties in the event of roof collapse or partial collapse. Simple couple roof is adopted with bamboo trusses for rafters. The rafters are fixed to the timber top beam by means of steel clamps. Bamboo mat board (BMB) gussets, in combination with mild steel bolts, are used for the truss rafter joints. For purl ins are used smaller diameter canes. Bamboo mat corrugated sheets (BMCS) are used for roof cladding. This type of roof doesn't transfer thrust onto supporting walls from gravity loading. The roof overhang of 400 mm is recommended.

Cladding and finish:-

Bamboo mat corrugated sheets (BMCS) are used for roof cladding. The sheets are anchored to purlins by means of J bolts. BMB is used for doors and window shutters.