Aircrete and earth-berming


  • Little Dragon Tamer Forum Facilitator

    @jwboing I imagine that an aircrete dome would provide a lot more than insulation even if underground. The way I figure it, the pressure of the soil would work together on all sides to hold the dome in place. The aircrete dome would be the form around which one could build an earth dome. In other words, the soil itself would merely add to the strength.

    I am no engineer, and have no experience building anything underground. This is merely what feels correct to me.



  • @zander
    Your spot on Zander! Yes, the structure would get stronger...



  • I built an earthbag home with intersecting vaults of ferrocement as a roof. I’m still experimenting with aircrete- did not want to use foam because it’s been implicated in the deaths of firemen and occupants due to the hydrogen cyanide gas that’s released when the stuff burns. I’ve been going for fireproof as opposed to flame resistant. No fire district where I live.
    I’m on well water and the water is hard which seems to be causing my attempts at aircrete to fail so far...
    In terms of a hobbit house that can actually heat and cook itself with the sun and earth, something resembling an earthship would be good- greenhouse for food and to heat the home without other inputs even in harsh winters. But tire wall construction is very laborious and I’ve found with earthbags I need to cover the bare bags so in effect attach stucco wire to both faces. It would be far easier to build two ferrocement walls with a gap and backfill / tamp earth into place. Or simply start with a ferrocement shell and bury it- ferrocement is famously strong. I would insert photos but that feature isn’t working with my phone. I’ve got many photos of the construction process at my non commercial, personal blog: TypeThisToSeeIt.com)



  • Great info and blog. Looking forward to following along!



  • @zander

    Has there been any sort of engineering report on aircrete? I’m getting my general contractor license and I know that I will have to objectively show the load bearing capability of this material. I will be building my houses underground. Thanks.



  • My guess is that u can do it with the right waterproofing plastic, u can look for green roofs materials.



  • @ignacio-dhome THANKS FOR THE REPLY!!!



  • @jwboing I know that alasteritameric paints are very flexible for roof waterproofing. They are commonly used for porches, roofs, and marine application. My main goal is to create an impermeable skin over the dome that will not crack, mold, or absorb. I have used this product several times which have held up over ten years. Granted, these are water shedding applications like roofs and decks. I would apply a fungicide as a preventative to the mixture to prevent mold if I am to bury it. I am currently on a project that I intend to use it on. It may be a while so if anyone has any experience below grade with this product please share.
    Thanks,
    Ignacio
    DHOME



  • @ignacio-dhome wanting to keep the bury your hobbit home topic alive as I see it as very beneficial to Us builders. Something that we should all consider is that aircrete has insulative properties but very little thermal mass, meaning it only stays warm or cold if you are expending energy. Thermal mass is what buffers the fluctuations in temperatures. EXAMPLE: Once it is heated it stays warm longer. The cold outside penetrates the structure more slowly because it has to get through the thermal mass to reach the interior. WIkIPEDIA: "In building design, thermal mass is a property of the mass of a building which enables it to store heat, providing "inertia" against temperature fluctuations." I feel that the most energy efficient dome is to bury it. The shape is also perfect for this application! Any thoughts?



  • This is an important thread. It would be great to get the input of some qualified engineers on this.


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