The hull is a series of wooden planks, long cut and carved by the expert hands of the carpenter, tied together using coir with coconut fibers stuffed in between. Kettuvallam /Kettuvallom (House Boat in Kerala) is steered by two persons in deep waters by means of oars. Long bamboo poles or 'punts' are used to propel in shadow areas. Bamboo beams sprouting off on the sides are used as foot holds for the same a senior oarsman and a helper control the Kettuvallam by singing songs and chants for inspiration. A box of sand, a few bricks in interior facilitate cooking on lower racks, with storage on the upper ones. Food and necessary items are stored in shelves sleeping quarter is on the uppermost racks, which have the best ventilation and accessibility. The interior space can also be used for the same when there is no cargo. Fresh water is stored in earthenware pots.
Due to these difficulties it becomes necessary to make some changes in the form so that a comfortable cruise was possible for tourist. The body was redesigned and remodeled to adapt for the new demands and functions. Certain elements had to be added and others removed to make it good enough for comfortable cruise. Height of roof was increased to get sufficient bed room. A plank was laid all through the length to reduce the disadvantages of curved shape of the hull for walking and comfortable seating. Windows and other openings were provided for light, airflow and view. The entrance is provided in the center of the linear axis with a top hung panel, which was supported by poles on either ends of the Valavara.
Most of the latest designs have incorporated 1 bed rooms, 2 bed rooms, 3 bedrooms & 4 bed rooms with a modern toilet, a living space and kitchen. For fixing the toilet seats, shower tray and ceramic floor finish a concrete slab is laid at the floor level. The soil outlet of the toilet seats are taken through the hull and let out to the following water beneath, the water is stored in a plastic tank kept at the top portion of the Valavara taking connection to the kitchen and toilets. The pipes, tank and other synthetic materials are covered with coir or panambu to maintain the aesthetic quality of the eco friendly materials. The air cylinders, which are of the metal body, are fixed to the underside of the cantilevered platforms at the entry points of Valavara. These cylinders help to balance the structure on water reducing its tilting to the sides to a minimum.
Modern house boats have been designed to meet the Green Palm/Gold Star Certifications by the Department of Tourism, Government of Kerala, which has recently enacted regulations, stipulating the standards of Kerala houseboats or Kettuvallams.
The colour of the Valavara is yellowish brown, which is the colour of the natural materials like panambu, coir and bamboo. It is a warmer colour comparing to the colour of the surrounding atmosphere. This gives a nice feeling of being inside the Vallam. Bamboo is used for the framework of the roof and splits of Bamboo are used for weaving mat for roofing. Bamboo poles are used for punting the Vallams. It is strong fiber and absorbs more carbon. Latest houseboats have modern interiors.
The interior furniture are either of cane or wood, floor carpeted with coir mat or wood panels. Valavara of panambu, Bamboo and coir all colours matching each other but bring the depth and variations in vision.
Lights and the patterns of lights and darkness it creates can call our attention to one a rear of our room de-emphasize others and thereby create division of spaces. At night the traditional hurricane lamp is used to light the interiors. Usually each one is hung from the ridge of Valavara one at front, one at rear and one or two accordingly for the living spaces. And mostly for half of a month there will be moonlight, which gives enough light, reflected on water. Modern Kettuvallam / Kettuvallom /House Boat uses Generator sets or Solar power to provide lighting and other power requirements inside the Houseboat.