Sustainable building with earth, corrugated galvanised iron and rebars

[Blokle]

TL;DR Summary

House building idea: earth filled walls made of corrugated galvanised iron and reinforcing bars

There are lot of people on the Internet trying to build a cheap and sustainable house. Inspired by them I came with the idea of building external walls of Corrugated galvanised iron (CGI) and rebars and fill them with earth / sand. The basic element of the wall structure is this rebar trapeze with hooks on the inner side:

Both its legs are placed fully into the ground up to the horizontal bottom bar (base). The above the ground height of the trapeze is 3 meter, the base - 1m and the top 0.5m Many such trapezes are placed at the perimeter of the future house and welded together into the following structure:

Next CGI sheets are perforated and hanged on both sides of the trapezes (on the inner hooks) starting from the bottom. Once they are filled with earth, next level of CGI sheets is added upon the lower level and also filled. During the filling, once the earth reaches their level - opposite hooks can be connected with metal wire to reduce chances of trapeze deformation. And so on until everything is filled up. Inner space can be divided into rooms using metal rods and drywall (gypsum panels). Ceiling and the roof will be supported by a separate metal rods structure of appropriate size. Some of those metal rods might be buried inside the earth of the walls. Now my primary questions...

1. Do you think such a construction is stable enough (on its own and in case of an earthquake)? If not, how long should the base and the top be, if the height should stay 3m?
2. What kind of rebars - radius, type, etc. should I use in such a case?

There are also some secondary questions, but they are less important...

3. Should I try to hermetically seal the holes of the CGI sheets or will the rainwater drain through the inner filling further to the ground?
4. What kind of ceiling would you recommend? The material should provide good thermal insulation (preferably also acoustic, be inflammable and not cause health problems).
5. How would you recommend to seal the connection between CGI sheets on the bottom and the ground?
6. What kind of CGI sheets would you recommend for the walls and which for the roof? (at the end the structure should be as cheap as possible, but not cheaper - safety first!)

 

[phinds]

Windows?

 

[Blokle]

Windows? And doors... - metal frames inside the walls that will hold the earth above it and on the sides. Interesting point regarding windows - should I cover the bottom part (the "windowsill")? I would prefer the earth to be exposed on the windowsill, so I can plant flowers there directly without a planter. On the other hand I don't know how the earth will behave there... will it be pressed out by the upper layers (like water would have), or not?...

 

[Baluncore]

Rebar with corrugated iron, will not survive in contact with soil. The hidden rebar will rust away and be gone, before you realise why you were crushed by the falling structure.

Build the walls from used tires, each with the upper sidewall cut out with a sharp knife. Stack a layer of tires like blocks. Screw the tires together vertically and horizontally with galvanised screws. Fill each layer with soil, then compact. Overlap and repeat. Paint the tire walls white to insulate.

Make the roof from corrugated iron, screwed to timber beams.

 

[jack action]

The galvanized steel sheets will rust. It takes a longer time but you will get holes from the humid earth within decades at most. Galvanized steel is not considered a cheap material either.

What would be the advantages compared to rammed earth houses?

 

[Baluncore]

Keep galvanised iron away from soil, it is designed to chemically react, which is why it is covered in expensive zinc.

Galvanised iron is good for roofs, because it weighs the least of all durable roofing per unit area. The water that runs off, can be used. Galvanised iron can hold the walls upright during earthquakes.

Tiles and slate roofs are very heavy, so require strong support and walls. People are killed by falling tiles.

Tiled roofs get blown apart during windstorms, and allow embers to enter the roof-space during bushfires.

Following a firestorm that entered a Canberra suburb, the houses that burned down had tile roofs, those with galvanised iron survived.