This is Part 2 of a three part series of our story of the construction of our house using locally available sustainable materials and skills. Click here to read Part 1. I am not sharing too many technical details for I am not an expert. Those who are interested in the finer details of the methods employed, please Comment below or write in to me at sudhakar2310@gmail.com~ 6 minute read

Cost and choice of Roof technique

The most important decision which influences cost is the size of the house. The smaller, the better; only, if you want to optimize for cost, obviously. Unless you are a crorepati. But then you wouldn’t be reading this blog, will you? :PWe wanted the house to offer enough space and privacy to two couples viz. Noushadya + me and my parents. We also wanted a space to host guests and therefore we built a spacious hall and patio. All rooms are therefore the size of 15 feet by 10 feet approximately. The patio is 300 sq ft. The total built up area is close to 1300 sq ft. This doesn’t include the area of the roof, of course.

After size, the next most important decision w.r.t. cost is the kind of roof that you want to build. The cost of the roof can vary from 75 to 500 per sq ft of the house based on the choice. The cost per square feet for building a conventional house with a concrete roof in Vikramasingapuram, Tirunelveli varies between 1300 to 1500 per sq ft. So, you can imagine how significant the cost of the roof is. In ascending order of cost, they are :

• Thatch roof
• Tiled roof
• Flat roof

A thatch roof made with coconut leaves needs to be changed every three years. A thatch with Palm has a higher lifetime. Both choices are extremely easy on the environment.A tiled roof – if not constructed perfectly – leaves gaps for insects and small reptiles to crawl through. So there was a little aversion from both my mother and Noushadya towards a tiled roof.Even though a flat roof was the most expensive roof technique, we chose to go ahead with it because we wanted a space on the roof to host students for workshops and for volunteers and guests for staying.

Madras Terrace

Madras Terrace is the vernacular on-the-way-to-be-forgotten technique that we relied on to build the roof. The roof is a tricky one to build because the friction between the baked bricks and the lime mortar is all that holds the roof together during construction. The roof looks very beautiful when left un-plastered. And most importantly, the roof has a tremendous capacity to keep the house relatively cool even during noon because of the number of layers it has.

The reason this roof has gone out of practice is because it is not economical compared to a concrete roof. None of the material in this roof viz. wood, small baked bricks or lime, is mass manufactured at scale. So, the only way to protect this art form is for people who can afford to employ this technique. The economic incentive simply doesn’t exist for people in small towns and villages, at least in the form of capital cash flow. Unless you take into consideration the energy saved in cooling the house, the lower carbon footprint of the processing and transportation of materials, a cost benefit analysis would always be in favour of a conventional baked bricks, cement and steel house.

On a side note : We need to either start pricing carbon and water as a civilizatiom, if we are going to sustain a capitalist economy or all citizens need to be educated on the implications of abusing sources and sinks, to have any hope of preventing runaway climate change , water wars and civilizational collapse. More on this in another blog post, maybe 🙂

A lot of you would be thinking that by cutting down trees for roof, we would be damaging the environment. The reality is quite the opposite actually. Only if wood is burnt or it starts decomposing aerobically or anaerobically in the soil when it falls down, will the carbon captured by the tree over its lifetime get released in the atmosphere. If you are going to cut a tree when it is at the end of its life and keep it in your house in the roof or as furniture or as doors / windows, the carbon captured by the tree is going to be locked in the wood till the house is maintained well.

Roof construction and the minimal cement use

We started building the house in the peak summer of May 2019. We completed the foundation and walls by August. Tirunelveli gets North East monsoons from October mid to December and we had to complete the roof before that. So we were in a race against time to complete the house. Procuring materials for the roof took more time than planned because we wanted mature palm wood for the beams and rafters. Everything fell into place in mid-September and by the first week of October, we had almost completed the roof.

This is when things fell apart majorly. Deepak and I had maintained from the beginning that we will avoid use of cement as much as possible. After we placed the tiles on the roof using lime mortar, we wanted to use a natural water proof mixture of lime and surkhi, instead of cement, to seal the gaps between the tiles. This insistence costed us dearly. Heavy monsoon arrived sooner than expected in October 2019 and rainwater leaked through the tiles during a heavy downpour late one fateful night. Because cob is just sun dried mud mix and doesn’t have any ceramic properties, the roof sunk in two places where the leakage was significant. And the flat roof was no longer flat.
This was the time we had to hear a lot of “I told you so”s from people involved in and witness to the construction. There are a lot of risks involved when someone inexperienced takes up a forgotten skill. The appetite for risk taking and potential for innovation has vanished from the land of jugaad, or it seems.To prevent any further damage, we constructed a thatch on top of the roof. We had to resume rebuilding parts of the wall and roof after the monsoon stopped in January 2020. We took some time to consult expert architects and regather our thoughts and ourselves. By the time we resumed construction, Coronavirus hit us in the middle of March.

Till the country was in lockdown, it was just Noushadya, Deepak and me rebuilding the sunken walls little by little. Only after lockdown ended, could we engage masons. We eventually completed the walls and roof by June 2020. To prevent potential of future damage to walls and roof because of water leakage, we ended up choosing to do a layer of tiles on the roof laid with cement mortar.
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Regards
Sudhakar