The Fired Mudbrick House Project
Jan de Rooden


Phase I 1984-85

Research 1985

Phase II 1986


Agni Jata



Building the mudhouse


First house 1984-85

An idea born
End of 1983 Ray Meeker read in the American Magazine "Ceramic Monthly" about a remarkable experiment by Iranian architect Nader Khalili.
In the late seventies, on one of his motorbike trips, Khalili passed through an Iranian village where all the houses appeared to be in very bad shape.
Some had collapsed under the weight of snow and melt water.
To his surprise he found one of the houses entirely intact. "Of course", the people who had drawn near, exclaimed: "that is the potter's kiln, those walls
are hard as a rock!"
The idea was born. Khalili did not rest before he had gathered enough oil to try to fire a few houses from the inside by aiming burners on the walls.
Thus it would have started once within that kiln, he thought.
He scored a partial success.

American-born Ray Meeker studied architecture at UCLA in Los Angeles and then changed to ceramics.
In 1971, together with Deborah Smith, he started a studio in the south Indian town of Pondicherry. When Tamil workers asked to be taught,
their studio developed into "Golden Bridge Pottery".
Like everybody else their people, too, were up against the problem of roofs that succumbed during the monsoon rains. Time and again therefore
they had to ask for an advance from their employers. A hard "pakka" roof, the highest ideal in India, was unattainable for them. They had to
depend on the traditional roofing of plaited palm leaves. Alas, each year this "keef" became more scarce and more expensive.
Ray knew at once: if anywhere there was to be found a location for a meaningful experiment to thoroughly test the feasibility of Khalili's idea,
Pondicherry ranked first.
A sound test should be based on ceramic principles. Experience and comprehension of kiln construction and firing techniques and ample understanding
of clay were a first requirement. Moreover this experiment would demand a hefty dose of organizational talent on the long route from the clay pit to
the final goal. Labourers on call had to be available. In and around Pondicherry all this was feasible.

Constantly engaged himself Ray, early 1984, asked me, if I would come and help him to start a project, that later would bear the name Fired
Mudbrick House Project
. I myself, having a sceptical attitude, had my doubts, just like Ray himself as he confided to me later, but only practice
could give a definite answer.
Moreover the concept and the location of execution were too seductive not to say yes.

Johnny agreed at once with the idea to leave our house for a period of time to work in India.
She immediately started to research mud architecture, whilst I went looking for the supplementary budget that we would need.
It was brought to my attention that Bilateral Relations of the Ministry of Culture probably would be interested in a project like ours. Participating
in a "Low cost housing" project indeed appealed to the staff. The fact, that the project would take place in India, and would employ local people
under management of men who had won their spurs in architecture and ceramics, to them was very convincing.
Twice the department of Bilateral Relations placed a budget at my disposal, that enabled me to participate in the Pondicherry project in the dry seasons
of 1984/5 and 1985/6.

Garb Aswan
Johnny's research soon showed that pre-eminently the source of information on building with mud bricks and mud was to be found in Nubia.
The Egyptian architect Hasan Fathy who devoted himself to the revival and improvement of mud architecture in his country, propagated the
Nubian vault. It seemed absolutely sensible that, before we started work in Pondicherry, we visited the Nubian mud brick villages situated on
the Nile river opposite Aswan, the origin of Fathy's inspiration.
Also for this study trip the office of Bilateral Relations provided us with the necessary funds.
In Egypt Johnny and I could thus observe on the spot Nubian vaults being erected and record the way of working. Especially in vast Garb Aswan
(West Aswan) in many neighborhoods new houses were being constructed in this distinct, impressive style. On the building site itself mud bricks
were being made and mud mortar and rendering mortar prepared. Effortless and without any guide the bricklayer built an impeccable vault over
the high sidewalls.
This stable and seemingly simple vault construction seemed to us the obvious solution for a house that had to be fired.
In Pondicherry Johnny's road diverged somewhat from mine. She had her task in the pottery. For the recently built salt kiln Johnny would help compose
slips and glaze liners from local raw materials.
For Ray and myself objective number one was to devise a campaign plan for the three or four dry months ahead, that would lead straight on to a fired
house from which, hopefully, we could continue building.
Campaign plan
  1. in Phase I we would start from a small house in the Nubian style;
  2. the volume of this building should minimally correspond with the smallest house in use locally;
    a plinth surface of 2 x 3 m.; a vault of about l.35 m. in height over walls of approx. 1.65 m.; this meant a front- and back wall of approx. 3.15 m.
    high in which ventilation slots would be made.
  3. before firing, the small building should be loaded as a kiln with mud bricks and tiles; these could accumulate heat during the firing; after the firing
    their proceeds would contribute to meeting the expense of the fuel.
  4. we would use the same fuel as the local brick makers namely casuarinas, a fast growing country wood with a high caloric value that is increasingly planted as a crop and does very well on the saline soils along the coast.
  5. parallel to Golden Bridge Pottery Ray had at his disposal a longish plot of land; on its border the house would be built and all the remaining terrain would serve as a production yard for the brick makers, that we would employ, as soon as the appropriate clay was available.
  6. they would make the vault bricks measuring: 26 x 16 x 5 cm with two diagonal grooves to give the clay mortar grip as well as the bricks for the walls;
    for the kiln load we would buy green (unfired) bricks from the brickyards in Tirukanchi,12 km away.

The brick makers wife, her baby safe in the shade,
makes the first vault bricks with grooves to give more grip.


Green bricks drying in the yard.

It was not too complicated to obtain suitable clay and clay bricks and to have these delivered, although green bricks had never been sold before.
The bookkeeper of Golden Bridge Pottery, together with a partner, had in lease a tract of land with good clay. On this land they had an extensive brick production going. This coincidence provided us, green as we were ourselves, with a welcome introduction.
It was more difficult to find good brickmakers and above all to keep them. When the family sowed or harvested, our brickyard lay deserted and also
after payday or when an advance was cashed, sometimes for days in a row no bricks were made.
However, as soon as sufficient vaultbricks were drying, we started building.
The brick layer and his helpers had little difficulty to adept themselves to the technique of building with mud bricks and mud mortar. I myself had
the sensation that from afar I was working at my familiar worktable. The walls grew daily but, alas, not continuously.
The brick supply and the availability of the brick makers ceased several times due to obscure reasons. Maybe one did not know what to think of
builders that bought green bricks, or one was out on a better price.
But in the end the walls were up and the construction of the vault could start.
From this moment on the bricklaying required the greatest care, I found. The angle from which I started building the vault was not right the first time,
and then we found that during the night the vault at half height had sagged outwards under its own weight. Fewer layers per day and hardly any or
no mud mortar, better still brick slivers etc. between the heads of the bricks were the solution. Only when I had invented a sort of guide, did the vault
grow quickly and straighter and soon after we could close it with a small ceremony.
Whilst the house dried, it was loaded with mud bricks and with tiles destined to cover the roof after firing.

Building the vault the Nubian way.

Insulation of the vault
To prevent heat loss, insulation of the vault was indispensable. For this we invented an ash mortar composed from a little water with a 0.25 : 1 : 6 mix
by volume of plastic clay, coarse sand and wood ash. This mixture was stuck on by hand in two layers, each about 2.5 cm thick, and then patted firmly.
Patting brings the clay to the surface, with moisture-containing salts from the ashes. Together, these components harden when drying and seal off
the insulation layer, protecting it against the wind and even against light rain, as was proved in practice.
Almost at the last moment heavy rains carried by freakish winds intervened. The sun had not yet risen but, hurrying nearer on my bike I spotted small
running figures on the building site and Ray busy high on the vault. Everybody had managed to find some protective material. When daylight came,
we saw that our building had not suffered any serious damage. To be secure the same day palm leaves for the piles of bricks and tarpaulin for the house
were bought. The heat of the sun would have the wood dry again in time for the start of the firing.

Firing the "Pilot House" .

Fired with enthusiasm
For firing this rather small structure and its loosely set load we anticipated a firing cycle of roughly 40 hours. In this hot climate a water-smoking period
of 12 hours seemed sufficient. The temperature during that period should not rise above 200 C. For the next 12 hours we estimated, that we should
reach red heat at 600 C. From then to the desired 960 C we reckoned we would need another 12 hours. This top temperature should be kept for
at least 4 hours to let the heat penetrate the vault. It all went somewhat differently.

Early Easter morning Ray and I lit the kindling in the left and right fire holes in the front side and backside. The tunnels in the centre were not needed during preheating. With pleasure we saw the fire move evenly to the middle of the kiln. However at midday a strong easterly wind sprang up and turbulence
blocked the airflow at the side of the compound wall. We improvised some changes, but only at sunset, when the wind declined, did we get an even fire
all over the kiln again. Around 10 p.m. the night stokers arrived. All day the temperature had not passed the 200 C. Now the stoking began to build up
the fire.
It was fascinating to see how almost melodiously the fire mouths and the vents reacted upon each other. Over the vault a veritable concert of flames
played together. Around midnight the temperature had risen to 300 C. Unfortunately both the "bosses", plagued by fever, then had to lie down for
a few hours after giving clear instructions. The stokers, now on their own, took to this firing in the same spirited way as they were used to handle the three-chamber pottery kiln.
One hour before sunrise we were back, and saw a glow through the vault near the back wall where a crack had appeared. Instead of filling it up with clay,
we decided to just put a layer of bricks over this area. That way we could follow more accurately the unhindered behaviour of the walls.
During our absence the heat had gone up so rapidly with this fast-burning wood, fed generously into a kiln which seemed designed and set for fast firing,
that the temperature had already passed 600 C. Now it was a matter of raising the temperature as slowly as possible.
When daylight came, we saw how the intense heat affected the structure. During the drying process some cracks had occurred in the side walls probably
due to setting. These opened up more, letting through a gush of steam. Then the sidewalls started to bulge in the middle, and the extension forces inside
also began lifting the front and the back walls away from the vault. The vault itself, however, remained undisturbed. The deformation in the sidewalls was definitive; the front and the back walls would start moving back as soon as the firing stopped and after cooling, they practically regained their original
When the day crew arrived we prepared for the last firing round, which should take until sunset. But already at the end of the morning the pyrometer
showed 960 C. Astonished Ray and I discussed, whether we might continue firing up to a 1000 C. However a glance at the centre tunnel showed bricks melting at stoking level. The firing was done. We decided to feed a final load of wood, while at all sides and on the vault all air-inlets, vents and stokeholes
were being bricked up and sealed off as fast as possible. The whole firing cycle had barely taken 26 hours.
The now cindering house would need four days to cool off. When on day five a beautiful load of bricks, like a harvest, had been carried out, we stood
in a sienna coloured room, which radiated a pleasing atmosphere. With once again a small ceremony and with Indian delicacies we let the serenity under
the cool vault affect us.
Firing results

When the insulation layer was removed from the vault, we could see to what extent our test had reached its main purpose: hardening through and
through the vaulted roof. The result was somewhat disappointing. A pinkish coloured brick appeared from under the ash mixture, still too soft and not yet erosion-proof.
Dr. Chamanlal Gupta, physicist and specialist on renewable energy, who with enthusiasm had followed our enterprise from the beginning, calculated,
that the temperature on the outside of the vault under the 5 cm insulation had been 615 C.
Had the insulation layer been l5 cm thick, then the necessary 850 C would have been reached, which would have produced red brick.


Rendering the walls with a mixture of laterite earth, lime and cement.

Though the structure was but a test house that should stand for a short time only, we wished to follow during the coming seasons also the effect
of the climate on the rendering.
As soon as the firing mouths, the air inlets below and the vents on the top were closed properly, the bricklayer and his mates started the finishing
work. The top of the walls were provided with a water drip of red brick in lime-cement mortar. The vault was covered with the newly-fired tiles set
in lime-clay mortar with a touch of cement. Then the walls were rendered outside and inside with a locally-used mixture of three parts red earth
(laterite), one part lime and a quarter cement. This gave the house the same warm deep ochre appearance of many of the surrounding Tamil houses.
However, as lime is said to have a hardening and waterproofing effect, we wanted to test this, too. So we whitewashed three sides of the house with
lime and a binder.
When our building stood there radiantly white, the people named it "the temple".

The finished  "Pilot House"
next to the  "Golden Bridge Pottery"  compound in Pondicherry, 1985.

The next steps
With the Pilot House hardly finished, each of us prepares himself for the next experiment.
It is arranged with Ray, that Johnny and I will be back in Pondicherry by the end of the year.
In our European environment we will, during the intervening eight months, gather as much information and ideas on mud brick building as possible.
Ray has already started the foundation for his next project: a hall with patio at the entrance of Golden Bridge Pottery.
On his drawing board the sketches grow day by day. Hassan Fathi's book "Architecture for the Poor" (ISBN 0-226-23916-0) seems
a source of inspiration for him, too.
On leaving the now so familiar Golden Bridge Pottery compound, we pass first the stack of bricks fired in the Pilot House and then stack after
stack of soft pale red bricks from neighboring brickyards. Those have been fired in "Skoves", a method where bricks are stacked in such a way,
that the stack itself becomes the kiln.
In the near future all these bricks will cover the exterior of the fired mud brick hall.