Building a house or buying one has become risky business these days as the consumers who are climbing up the four and eight floors of two of Bangalore’s consumer courts, to get back their money from builders, will tell you.  

The report of the Task Fource on Housing is depressing. In it, The Centre for Symbiosis of Technology, Environment and Management (STEM) has pointed out that the total housing deficit in Karnataka is expected to reach 21.89 lakhs. The districts with the highest percentage of houseless families are Raichur, Bellary, Bangalore Rural, Chitradurga and Mysore.  

One of the important recommendations the Task Force has made is that the Government should promote cost-effective building technology. It says, “The high cost of traditional building materials makes housing unaffordable to a large section of the poor. Moreover, the production of traditional building materials is highly energy-intensive and the high consumption of energy has adverse effects on the environment. For example, traditional brick and roofing tile industries use firewood as fuel.” 

It points out that many alternative building materials and techniques have been developed. But they have yet to become popular with consumers as well as builders and architects. Cost-effective technology should become main-stream technology which will bring down the cost of construction.  
If you are planning to build a house, these alternative techniques may interest you. According to K R Ganesh, one of Bangalore’s innovative architects, what is 'appropriate' could be elaborated as "The process and product of 'limiting' the 'wants’ by eliminating the superfluous and identifying the inevitable 'needs’ and satiating the same".  

The popular RCC roof slabs for the affordable and asbestos cement sheet roof for the non-affordable (and industrial/ large span roofs) was the common scene that was in vogue in architectural construction. During late seventies, filler slab options initiated by Laurie Baker in Kerala for roofs had caught the attention of designers. During the eighties, alternate roof (floor) options were explored simultaneously at CBRI Roorkee, Building Centre at Auroville and ASTRA (Application of Science and Technology for Rural Areas), Indian Institute of Science, Bangalore. Let us look into alternate roofing options which have been developed with the help/aid of ASTRA. 

The roofing alternatives like vaults and domes have a tendency to curb the vertical growth or may hinder the possibility of a floor above. Filler slabs with a wide variety of substituting material options successfully help in replacing redundant concrete in the tension zone. But, they still necessitate centering/ form work and there will be lack of control in the quality of ceiling finishes. 

It is in this context that prefabricated and partially prefabricated roof components become relevant with respect to effective optimisation of cost, energy, time, material, thermal insulation and user comfort. 
Precast FC/ RC Purlins/ Joists/ Rafters 

Of the successfully attempted and implemented alternate roofing options are the precast/ partially prefabricated RCC joists/ rafters/ purlins supporting above - 
1. Precast arched RCC/ tiled panels  
2. Hollow (Hourdi) Clay Blocks  
3. Stone (Sedimentary) Slabs  
4. Fly Ash Cement/ Lime (Aerocon-air+concrete) Blocks  
5. Precast RC Channels/ Panels  
6. Reinforced Clay Tile Panels (Precast)  
7. Asbestos Cement (AC) Corrugated Sheets  
8. Reinforced Brick/ Hollow Clay Block Panels (Precast) for Roofs/ Floors . 
Arched RCPanel Casting 

The advantages of these above alternative roofing systems are found to be - 
1. Steel and Cement consumption kept to minimum, resulting in cost and energy efficiency. 
2. Formwork/ Centering/ Scaffolding is minimal. 
3. Obvious savings in plastering and finishes. 
4. Components/.Parts/.Elements/ of roof could be simultaneously made/ got ready, along with wall construction, resulting in better time management. 
5. Thermal insulation, leading to user comfort. 
6. Aesthetically challenging options facilitating user acceptance and receptivity. 
7. Reduction in self-weight in certain cases. 

Amongst the possible alternatives developed over the past decade for roofs, these experimental masonry options and patterns offer scope and potential to determine the aspect of strength, stability, erosion and longevity. Laboratory experiments and results exude confidence to the designer and builder. Practical demonstrations alone, on site, backed with results of experiments instill confidence in user and common man. It is at this stage that the role of practising architects becomes crucial in technology transfer, signifying the importance imminent in getting implemented the alternative options. 

All the houses which Ganesh has built have used these alternative roofing options which give them a different, exciting and innovative look. They are also environmentally friendly. He can be contacted at: 3354410.