Domegaia AirCrete workshop day 1 and 2

Domegaia AirCrete workshop day 1 and 2

Dec 10, 2017

We’ve decided to participate in a workshop, created by Domegaia on how to create a dome made out of AirCrete . The workshop includes thirty participants from all four corners of the world and is in collaboration with Agathe, the founder of the orphanage project and her team who work alongside Earthship .

The long-term objective is to place a self-sustaining orphanage that would cater its own water through the collection rainwater, generate its own power through solar panels, have a water treatment system, use trash as materials for construction, as well as create an environment where the orphanage would be able to produce their own food. We want to be part of this venture so that we can better familiarize ourselves with the principles of self-sustaining builds while helping a community.

We were initially seduced by the stature of the workshop. It had been popularized on Domegaia’s website with Steve Areen’s beautiful domed construction in Thailand , that had only lasted six weeks worth of work jumbled with an attractive low costing price of $9,000. The workshop seemed promising, unfortunately, we were soon to find out that Areen’s dome was not built with AirCrete but rather with regular cement. The news disappointed many participants, including ourselves.

Our curiosity peaked, as we wondered what AirCrete really consisted of. Upon research, we were able to deduce that since it is a blend of cement, it is more affordable and slightly more eco-friendly. Not only is it water and fire proof but it also acts as a good shield against pesky bugs. It’s a material that is easy to work with, once dry, it can be cut into various shapes and sizes with the help of a saw and can withstand nails. Within AirCrete, bubbles of air (arising from the mixture of cement and soap) make the overall product lightweight and an excellent candidate for insulation.

Prepping and Placement

The location of the orphanage is a 40 minutes walk from “downtown” Mazunte. The road leading there had been cleared a few days prior to the workshop and became 4X4 accessible.

It required enormous effort and organization for Agathe and her crew to have everything set up. Aside from a visit in September, one week before participants arrived in december, they were able to prep the terrain and camping site, build a foundation as well as install a drainage system around the dome.

Inspired by Earthship, the foundation was made with used tires packed with gravel.
A cement beam connects the foundation to the dome.
The floor is then levelled with the tires with compacted earth. Unfortunately, the French drain is not viewable in the image since it has been covered with gravel. Essentially, the trench surrounding the dome is slightly inclined on one side. The pipe that is placed above it is perforated on top, enabling gravity to naturally evacuate the water within.

The objective of our blog is to document our learning path and journey so that it may possibly inspire other people to do the same, and/or to simply have an open discussion. Please feel free to comment or ask us questions in the section below! We’d love to hear what you have to say, if you’d like to keep reading, following is a recap of our first two days at the AirCrete workshop.

Day one

Since the structure of the dome is principally made of bricks, we spent the first day assembling four molds so that we could set the AirCrete within. The molds were used during the whole duration of the construction and were made of 2” x 4” pieces of wood attached by metal latches ordered on Amazon with an inlay made from a garbage bag (so that the mixture would not leak out).

Completed AirCrete mold
Latches installed on all four corners
Knife used for cutting the bricks

The window

The window’s round mold was made of a thin plywood plank that could be easily bent to create the desired shape, circled by metal rods and secured with nails. Space in the interior/exterior of the mold enabled us to pour in the AirCrete mixture.

In order to have a perfectly shaped circle, the diameter of the window had to be calculated. Using a mathematical formula circumference = diameter * 3.14 we were able to establish the proper length needed to cut the metal rods.

Following, we used a bending contraption , developed and sold by Domegaia for 375$…The workshop clearly stated us the importance of bending the metal slowly until both ends meet. If the latter is not achieved, then it becomes extremely difficult to bend the metal in its opposite direction.

Bender, developed by Domegaia. Propelled by a drill, it curves the metal rods that will later make the mold’s circumference of the the window. Once the rods are curved and assembled, we placed the plywood planks completely within them.

We then repeated the process to create the interior part of the window’s mold. In our case, the exterior diameter consisted of 69 inches and the interior diameter was of 59 inches. The thickness of the window resulted in 10 inches. To this day, this is the largest window constructed by Domegaia.

Note: the image shows incomplete plywood surrounding.
Completed interior and exterior mold
Completed window form where we added fabric so the cement won't stick to the plywood.
Pouring cement between the interior and exterior mold

AirCrete Bricks

Let’s talk about AirCrete bricks! They are composed of a specific ratio of water, cement and soap. The lather of water and soap is created with the help of a machine called the Little Dragon (made by Domegaia). This machine, powered electrically, needs an air compressor in order to get that perfect foam density (the key element to a successful AirCrete mix). With the help of a scale and a 1L container, we were able to ensure that the foam we generated weighted between 90-100 grams. Needless to say, we subtracted the weight of the container first before we weighed the foam, of course!

If the mixture ratio is not done right, then the bricks become unusable. They will naturally come apart before even being used. Speaking from experience, we had lost half of our bricks on the first day because of this same mistake. However, we are unsure if it was due to the amount of soap being mixed in, or if it was due to the generator not receiving enough power to add more air into the lather. Regardless, it is important to properly test out the equipment before going into a heavier production and regularly double-check the machines to make sure they are still functioning properly to avoid setbacks.

Ideally, once the weight and ratio of the foam has been acquired, the simple step of pouring it into a barrel follows. Amongst the foam, water and cement reside and are blended together, from the top to the bottom of the barrel to make a homogenous mix.

As soon as the mix is ready, we then pour it into the molds with the help of two or three other people. In order to not have the bricks stick to the mold once dry, it is important to add vegetable oil to the plastic bag (inlay) prior to pouring.

Day two

The bricks had been cut on the second day. We ended up using more brute force to cut them since we had not properly made the AirCrete mix. Usually, the bricks are easier to cut through.

In general, the bricks attain their overall strength within 28 days. Be it as it may, the bricks are still usable within a 24 hours frame and is recommended to be cut as of this threshold for ease. Although resilient, it is important to handle the bricks with care, as they are still very fragile. Once we completed the task of separating bricks from the mold and cutting them, we assembled them near the dome. We proceeded to clean the molds and aptly began to refill them as the next batch. The whole entire process: cutting the bricks, cleaning the molds, ensuring proper ratios of foam, blending in all the materials to make AirCrete, took us a good half of the day, if not longer. By then, the circular window mold had been completed and we hastily added the AirCrete within it.

Little Dragon

More structural content was needed to make the arched entrance. The materials and process used were of the same fashion as that of the rounded window, except that the metal rods varied in size and had a parabolic shape.

Brick placement

Now, for the fun part of the construction, creating the dome! The first step was to place a compass in the center space. Just as with done with conventional bricks, we sandwiched each slab with mortar and placed them one on-top of the other. The compass had played a vital role for us since it was used as the main guide for placing our bricks at the right spot and angle. For the first row, we placed a shim on the interior side of the lower-end of the brick in order for it to be slightly inclined towards the exterior of the dome. We then were able to staple and hold the bricks side-by-side with the help of pieces of metal shaped in the letter “W”.

There you have it, the first two days of our experience at the AirCrete workshop, if you’re interested in finding out what happens next with the dome, stay tuned for our next blog post!


Translated by Caitlin

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