Bamboo is an attractive alternative for flooring because of its physical similarities to hardwoods. Bamboo floor manufacturers promote its strength and durability as well as its resistance to insects and moisture, and they say the material is also “eco friendly”. The hardness of traditional bamboo flooring ranges from 11.8 (carbonized horizontal) to around 13.8 (natural), while newer manufacturing techniques including strand woven bamboo flooring range from 30.0 to over 50.0 using the Janka hardness test. Different forms of bamboo flooring exist. Each varies in its manufacturing process and differs largely based on economic viability and local preferences.
The most common form, particularly in south-east Asia, uses thin bamboo stems that are cut as flat as possible. They are cut to similar lengths and can be stained, varnished, or simply used as is. They are then nailed down to wooden beams or bigger pieces of bamboo stems. This form results in more space between each bamboo stem; flatness and tightness is not emphasized. This technique is usually used on stilted houses, resulting in better air circulation especially during the warmer summer months.
Bamboo flooring is typically made by slicing mature bamboo poles or culms into strips. These culms are crosscut to length and then sliced into strips depending on the width desired. The outer skin and nodes are removed. To remove starch and sugars the strips of bamboo are boiled in a solution of boric acid or lime. The bamboo is then dried and planed.
Natural bamboo colour is similar to beech wood. If a darker colour similar to oak is desired, the bamboo goes through a carbonizing process of steaming under controlled pressure and heat. The carbonizing process can reduce the floor’s final hardness significantly compared to non-carbonized bamboo, rendering it softer.
Manufactured bamboo floors are typically made available in planks with either vertical- or horizontal-grain orientation. In vertical bamboo floors, the component pieces are stood vertically on their narrowest edge and then press laminated side to side. The effect is a lined, almost uniform look to the surface of the finished floor plank. In horizontal bamboo floors, the slats are arranged in a horizontal direction, on their widest edge, and then joined side by side with adjacent pieces using a high-pressure laminate system. The characteristic nodes of the bamboo are visible on the finished horizontal surface.