If you remember our last blog on this topic, it was posted after the heavy rains and floods that hit Tirunelveli in December 2023. We had lost the roof & walls to the heavy downpour and questionable construction design. Compost toilet was our first experiment in construction with local sustainable materials and techniques when we moved to the farm in 2018. When we heard the roof collapse, I was heartbroken. But eventually, we came to terms with our failure and started reconstruction in January 2024.

In May 2024, we completed the re-construction of the walls and roof of the compost toilet albeit with different techniques. We also added a bathroom adjacent to the compost toilet.

Before I talk about the construction styles we employed, let me talk a little about the current events.

Floods hit Tamil Nadu – second year in a row

The intensity of flood that hit South Tamil Nadu this December was even stronger than last year – what started as a drizzle on 11th December night ended only on 14th December. While this duration might not come as a surprise to the Mumbaikar in me, it was a surprise to the Tamizhan living in the plains of Tamil Nadu. Most of Tamil Nadu except the hills gets an average of ~ 1000 mm rainfall throughout the year – ~500 mm of which is delivered during the monsoon months of November and December. Last 2 years, the 500 mm of rainfall pours in just 2 days rather than spread across 2 months. The land and urban design is not accustomed to this copious quantities of water in such a short duration. And a lot of people are not prepared to handle this situation.

Thankfully it did not cause any damage to any of the buildings at the farm this time. There was only one major incident though – a huge clump of bamboo was uprooted from right at the edge of the fence near the main gate. The clump got obstructed by a bridge across the stream and was thrown over it. Only after the flood waters receded on Monday, 3 days after the deluge, we could trim this clump and clear the way for vehicles to enter the farm. But this was the first time flood water entered the houses in a few localities of Vikramasingapuram when the main Thamirabarani canal overflew.

The flood last year brought back memories from last year. I realized that while i had covered the failures of the construction in a blog post, I hadn’t written about the resurrection of the compost toilet. So here goes : better late than never! 🙂

Compost Toilet Walls

Sun-dried bricks need to be completely dry to ensure that withstand the test of time. Lower overhang length was the major reason sun-dried bricks got wet in the last construction. Baked bricks have a higher compressive strength and do not get affected by rain. The load bearing walls were constructed with baked bricks and mud mortar.

I am of the opinion that we need to keep the use of baked bricks to the minimum possible. Baked bricks consume a lot of energy in the form of firewood. For single-storied structures, the higher compressive strength of baked bricks are simply not needed. So, other than the 3 load bearing walls, the rest of the walls are built with the wattle & daub technique.

1. Harvest

The woven wattle framework was with bamboo and ipomea carnea, both sourced from right outside the farm bounds – from poromboke land.

If you haven’t heard this song about poromboke, you should give this song, by T M Krishna under Vettiver Collective’s banner, a listen

https://www.youtube.com/watch?v=82jFyeV5AHM

The thin bamboo sticks was harvested from the edge of the canal on the southern edge of the farm. And then ipomea carnea reeds were trimmed fresh from the nearby pond, north of the farm, which was mostly dry after the intense summer. Ipomea Carnea is known as neyveli kattamanakku or oothaanpetti in Tamil.

2. Wattle

The bamboo was kept upright with a short 1 foot tall cob wall above the composting chambers. The Bamboo was tied to the Palmyra Rafters with Palmyra frond fibres.

Ipomea Carnea is woven one by one across the width of the bamboo frame to build a beautiful looking framework. The thickness of the reeds are not uniform across the length. So, the direction of the reeds needed to be alternated.

The weave looked so beautiful that i didn’t feel like even daubing it with mud. I recommended to Noushy that we use a curtain instead. But then it would have afforded less privacy to the toilet & bathroom users. So, Noushy rejected this plan. Haha.

3. Daub

We had recently dug a pit for rainwater harvesting tank. We built a parking garage on top of this eventually. More on this structure in a future blog.

So, the clayey soil for the daubing was sourced from the farm itself. Extremely hyper local source the mud is. The local soil is clayey. So we had to buy m-sand to bring the clay proportion to around 20%. We added a fermented mixture of Kadukkai / Haritaki to the mud mix. We also added a neem turmeric copper sulphate solution for termite and fungal resistance.

Daubing is a joyous activity and best done as a community. And that is what we did!

Compost Toilet Plasters

The plasters in the interior walls of the dry compost toilet are with a simple mud mortar. Because they will not be getting wet, there is no risk of the plasters peeling off.

The external plasters are done with a simple lime sand mortar. We used egg white as an adhesive. We mixed aavaram poo powder to bring a light red tinge in some of the walls.

Compost Toilet Roof

The madras terrace flat roof is a heavy roof. This was the 2nd major reason that the walls collapsed in the first construction. The Madras terrace that we tried out for the small 5 ft by 10 ft compost toilet in 2019 was actually a trial before we did the roof for the 25 ft vs 45 ft house in 2020.

This time, we decided to do a tiled roof. The materials for which were all locally sourced. The palmyra rafters which was used in the flat roof were cut to size and a few more were sourced from a local old house which was being demolished. Because we were using recycled wood, the cost of the rafters was much lesser.

Terracotta roof tiles were also given away for free by a well wisher from the nearby village. We only had to bear the transportation charges to the farm.

Local carpenters completed the palmyra framework right after the load bearing walls were complete, before we started the wattle & daub walls. Local masons Kumaresan, Murugan and Raja placed the tiles on the framework along with the able assistants : Pazhani and Kumar.

Bathroom

We have extended the compost toilet structure to house a bathroom as well. Vaanavil Farm Stay, whose construction we are about to complete this month, has attached bathroom & toilet in both rooms. The 2 rooms will be able to host only 8 people max. But we envisage that we will be hosting larger groups in the future, who will sleep overnight in shared spaces like the terrace of Bhoomi, the earth house, and Vaanavil Farm Stay or anywhere under the open sky in the farm. So, to provide bathing space, we just thought that it is prudent to construct a bathroom space. It is a small 5 x 7 feet space with a tap and no shower.

The internal plasters are with a simple lime mortar. This plastered wall was painted with lime wash. And then a couple of coats of linseed oil was done to waterproof. It has since been used only a few time as a bathroom. Only time will tell if the waterproofing technique will suffice in the long run.

Cement plasters and ceramic tiles are energy intense to manufacture and transport. We wanted to avoid them because this is simple construction which might not be used through out the year.

People

This was Vanya’s first natural construction. She joined us in daubing the wattled walls. She thoroughly enjoyed the process.

My cousins from Mumbai, Kiran and Nirmal, participated in the construction when they visited for about a week during the intense summer of March. At the same time, we also had a couple of volunteers from Germany, Stella and Lenny, who were completely involved in the weaving of the wattle and daubing of the walls. Lenny wants to construct with clay in the future and therefore was keen on learning hands-on some techniques. Without them, we would have had to employ more people to complete the construction! Thanks to their efforts, we saved some money, got some labour in barter for the amazing food that Noushy served to all of us 🙂

Without the help of my parents and Noushy’s kitchen skills, we would not have been able to host so many people at the same time. Team work is the best work! 🙂

Regards

Sudhakar

9043824660