Foundations and footers. What you did.

  • Hi.
    I am curious what sort of preperations you made to pour the floor/ foundation for your dome. Did you did a footer? How wide and how deep? Did you use aircrete or regular concrete for the footer? Did you use any reinforcing materials like rebar or wire in the footer or floor. Did you tamp or use base course gravel?
    I am starting a dome and wonder if aircrete has the compression strength th support tge weight of a larger dome.
    Thanks for you time.

  • Workshop Instructor

    Use regular concrete for footers. #aircrete has very little compressive strength.

  • I see that you said aircrete has very little compressive strength. Do you think it has enough compressive strength to be used as footers @18" wide X 5.5" thick that would be used to set steps on, coming off of a lanai? I also want to make the steps out of aircrete. Maybe from blocks that I make from forms that I pour aircrete into. I read that mixing sand in aircrete can increase its strength. Would that be sufficient in footings with a load of only steps and people stepping on them--or just stick regular concrete?

  • Workshop Instructor

    @Jim_Scan honestly, unless you use an over laymen like tile for the #aircrete, I would use concrete. As for the footers as well... Rebar, concrete and the such.

  • @Jim_Scan
    I have been experimenting with aircrete to level the area under my hawaiian stilt shack. I think it is string enough for sidewalks and steps with these notes from my tests:
    It cracks if you drive a car on it.
    Batches vary a bit in strength and texture for finishing and it is difficult to impossible to get a polished finish.
    Building forms is easy...I even used cardboard boxes as a test.
    Dragging heavy things like a 50 gallon drum about will score the surface.
    My solution for these things is to put a 1/4 to 1\2 inch layer of store bought mortar and finish it like any concrete job.

  • I thank you both for the information. As mentioned I don't think there will be much of a load on the steps and the footer under them. I too am in Hawaii--on the Big Island in North Kohala. I want to use aircrete but only if it is 'doable'. I was reading in the some of the posts here, that the use of a 'fabric' adds the much-needed strength to the building as a whole. I'm wondering if it will add some compression strength to the steps and footing if I were to wrap them, once completed in the fabric that is set in 'airmortar'. I am very new to this and want to do more with aircrete in the future, that is why I would like to figure out a way to do this footing and set of steps using it, instead of the 'quickcrete' that I have used in the past for projects. I like the idea of a 1/2" of mortar over everything and even using tile over the aircrete seems like it would certainly disperse the compression load. Any and all comment/suggestions are more than welcome. Mahalo for getting back to me. Aloha...

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