Curved Rammed Earth Wall, Part 1. Recycling Technique

PART 1 March 2025

Holistic Architecture and Materials

The most costly part of rammed earth construction is the formwork. Corrugated iron roofs in Costa Rica must be replaced regularly, creating waste.

Follow up our work in the next story PART 2 in order to see how the wall will look like !

Benefits of PART 1. for the community :

- Classrooms and meeting point:

- Use of the local red earth

- Sensation of the local earth

- Supportive learning atmosphere (classroom)

- Meeting point for visitors and children, but also “play castle”

- Cost saving through use of the earth and less concrete and purchased sand etc.

- Reuse of used corrugated iron

- A. Formwork for the wall

- B. Reuse of the used material in the roof by stabilization with cement. (Geotextile)

- Natural ventilation and cooling . (Classroom)

- Development of simple techniques. Everyone can help.

- Creating grounded places

- Creating identity, through Intuitive, Holistic, Authentic Methods IHA

- Architecture connected to the place

- Thereby self-empowerment for self-building

Development process

In intuitive, holistic, authentic architecture IHA one receives buildings as a whole in a moment. For this there are special intuitive methods and an immersion in the deep energy of the place, genius loci and the people.

( See Bloom: Design process Coliazul Campus Costa Rica )

https://bloomnetwork.earth/view/coliazul-holistic-design-architecture-390f9721b537

Often, however, they not only bring entire building forms and overall designs that emerge in the landscape in the intuitive work, they also sometimes bring new technologies that are precisely tailored to the situation, even those techniques that the architect does not know or that have never been used.

Sometimes it takes weeks to understand them !

It is the step in the history of consciousness from inventing and devising to holistic “receiving”. This development is taking place in the world today.

In the case described below, I literally received the technical design in my womb,

While the whole building ensemble was created on site, as described in the previous Bloom report, the classrooms came as a whole sitting in my studio, the form together with the technology, done with a material I never used in other countries: corrugated metall.

I was amazed that clay walls came directly in a corrugated metal form, something I had never seen before.

The shape of the classrooms

The classrooms are oval and open up in a spiral shape at one point, where the entrance is.

They are made of rammed earth all around. The red earth of Costa Rica literally envelops the children. This shape may seem strange at first, but then you begin to understand why.

Educational

We live here on the edge of the jungle, our children spend the whole day in the sun in the open air among the lush plants. This draws consciousness outwards. It is not uncommon for even the best teachers to have discipline problems.

The shape and the material bring a positive concentration and grounding.

It's easy to imagine.

Technical and functional advantages

( Test blocks with different propotions of sand and local earth )

Sound insulation through rammed earth:

At the same time, the children in one class can sing Beethoven's 9th Ode to Joy and in the other class, for example, indigenous songs. This is not possible in a normal house in Costa Rica, where there is hardly any insulation.

Cooling

The wall itself regulates the temperature.

There are also pipes in the wall that bring in air, and a skylight at the top in the middle where the air can escape.

Natural ventilation. The temperature difference from shadow to light creates movement.

We have:

- Natural concentration

- Natural sound insulation

- Natural ventilation.

Corrugated iron formwork:

It was really amazing that the building technology came with it:

The curved clay walls were cast in molds made of used corrugated iron.

This used corrugated iron was literally lying around on the land, so it didn't have to be transported there.

Rammed earth can also be transported from far away or even bought in bags (Claytech), we used the wonderful red local earth.

The complex thing with rammed earth is generally the formwork. That's where the labor and material costs are. That's why very few people opt for this technique. As long as the walls are straight, this is still relatively easy to create. If the walls are curved, more work is required.

This is why curved walls are often avoided, as is rammed earth in general. The stability of the molds must be extremely good, because the tamping pressure must be enormous.

That is, because we compress each layer of earth from 10 cm to 6 cm. i.e. between ⅓ and ½.

We were lucky that someone had stored old, used corrugated iron on the land, which is available in abundance in Costa Rica and if the roof rusts, it has to be replaced.

Statics and technology

Corrugated iron is not just a surface, it is so suitable because it has a natural stability in the running line by the wave.

If you place it bent on the ground, it already can stand on its own.

We connect two sheets of corrugated iron with threaded rods and place short 20 cm 1 inch water pipes between them as spacers for even spacing.

The resulting curved double walls provide enormous stability, just like the dome of Santa “Maria del Fiore” in Florence.

Of course, the whole wall needs an appropriate foundation in the tropics. 30 cm and for large walls, such as in the classrooms up to 5.50 m, also vertical concrete supports and horizontal ring anchors every 2.5 m, for example.

This is also important for the building authorities. This can also be used for design purposes.

Test wall

Diamante Luz- Coliazul Info Station

To test the earth and the new technology, we decided to build a small 5 m long information wall.

Both projects are to be presented at the junction between the Coliazul and Diamante Luz sites.

- A meeting point with a bench and a roof is to be created.

- Broken glass gravel layer, bottle ceramic recycling

- Concrete strip foundation with inlaid whole old bottles

- Reinforcing steel

- Natural stone supports built from surrounding field stones. Left and right

- Round window shape made from a car tire as a form.

- Wall material Local clay + 11% cement + 8% lime. You choose what feels good for you.

In internet You find different proportions.

- Roof Steel construction and recycled corrugated sheet metal

- Protective layer made of concrete-covered fabric

- Colorful protective coating

- Planting with jungle plants, dragon tree etc.

Bench

The bench is not only useful for sitting on, during the construction phase it is an important factor in stabilization. It moves upwards supported by blocks and presses into the bend. The concave side is already stabilizing due to its shape. This is also an interesting secret of how aesthetics, pedagogy, statics, sustainability and recycling go hand in hand here and form a whole, indeed this solution provides answers to many questions. The seat supports this even further. To ensure that it nestles perfectly into the concave, I decided to cast it out of concrete when I woke up this morning. A material that I would not normally use in the northern hemisphere. In the tropics, however, concrete is important and even ideal in certain places. For outdoor facilities, 3 factors: In the tropics, however, concrete is important and even ideal in certain places. There are 3 factors to consider when it comes to outdoor installations that gnaw away at natural materials: rain, sun and hormigas...or termites or ants. But the bottom is also pleasantly cooled when sitting.

Natural stone corners

Left and right we did natural walls to support the wall.

This is not necessary when it is a whole wall.

In the picture below the form work is not open jet.

First steps

1. Digging foundations

2. Adding rammed recycled glas for strong support and water drainage

3. Adding rammed recyckled ceramics if You like.

4. puring concret to + - 0.

5. Adding recycled bottles to safe concret

6. Drilling holes in the metal sheets in a regular pattern in both the front and back of the metal sheets to connect front and back.

( Make sure that they are a little bigger then the threaded rot )

7 . Fit in threaded rods between the metal sheets and plastic pipes in the size of the future wall to keep distance.

We connect them with butterfly. Then we poor concret to 30 cm for example to keep the rammed earth in a distance to the ground. ( Very important in the tropics for the rain season. We are in Costa Rica )

8. As it is an experimantal wall we choose natural stone corners to hold it.

9. Mix clay, cement and lime in the way You like.

10. Add a little water and test. when it falls from 70 cm it should not totaly destroy.

11. Put the mix in the form and condense from 10 cm to arround 6 cm.

Follow up our work in the next story PART 2 in order to see how the wall will look like !

Conclusion

You should definitely make test blocks with the local clay but also test walls.

Our test blocks about 1 x 1 foot are hard as concrete, although they have been in the tropical rainy season rain for months now.

The openened rammed earth wall has but against expect a too soft surface.

Hardening agents such as water glass were not available in Costa Rica.

A clay plaster made of local clay (1.5 parts clay, 2 parts sand and 1.5 parts cement) has now sealed the surface perfectly.

Learningpoints for working with rammed earth and corrugated metal form-work

1. The wall must not be too thin about 1 foot minimum
2. The corrugated sheet metal plates should have a systematic perforation, which is thereby easy to push up.
3. The formwork should be opened at the latest after 24 hours and moved up.
4. Mix well, preferably with cement mixer
5. You should not use lime
6. Small layers, compacting from 2 inch to 1 inch
7. We had hand rammers with sawn shaft. For large areas it is recommended to have technical rammers.
8. Here in the tropics, rammed earth is rarely used. One of the reasons can be that it is getting often moldy. One of the reasons can be the oil which is used as a release agent on the sheets. A spray bottle of chlorine can inhibit growth.

Look up Part 2

Curved rammed earth wall. Part 2

clay plaster finish