Homemade Foam Generator / Solar Heat Sink Floor

Well I finally got around to making my foam generator so now I can finally make some aircrete. I plan to make an insulated sub floor for like 1/2 the price of blue foam and then cover with 1 or 2 inches of harder concrete or maybe an earthen floor, that will act as a heat sink when the sun shins on it. I plan to make a few aircrete videos so make sure you subscribe so you won't miss out and thanks for watching.

Hello William,
I was curious how big is the area you are covering with aircrete ?
Is the floor under where the aircrete will rest dry year round or do you plan on put down some plastic or other membrane first?
Who's recipe are you going to follow for the insulated floor?

Hey Burton, sorry I was at the other homestead for a few days so I had no contact with the civilized world, lol, no cell service unless I go uphill about a half a mile.
It does stay dry and dusty so I really see no need for plastic and I really need to research and experiment with it to get the right mixture. I was watching Aircrete Harry and he used baking soda in the mix and ended up with a really hard mix. What I have made so far takes a couple of days to set up enough to where you will not crush it if I touch it very lightly. I may also try an excellerant.
I'm doing a 20 x 40 ft. area but 10 sq. ft. at a time. If you have any ideas or suggestions feel free to comment. I have a lot to learn about this stuff and what I have done shinks about 5 to 10 percent, I think using Drexel may help with that. I think I need to watch more Honey Do Carpenter and Aircrete Harry.

A person could make Papercrete for an insulated floor as well.

I do not have passive solar in my house, but I do have geothermal, and adding 400 ton of rock under the concrete slab has really helped increase my geothermal btu's. Last year I was not living in this house, and unheated, unlived n even, the house never got below 44 degrees. That seems cold, but it was -7 degrees below zero outside in (F). That is pretty chilly, and yet a home to be above freezing just by a geothermal slab.

I have made one as well.      I have made a L rocket stove with the design.


I have been thinking that would could combine this with broken concrete to fill a large void in a short amount of time.


I like your idea of aircrete on the bottom then to have concrete on top of that....

Mart Hale wrote:I like your idea of aircrete on the bottom then to have concrete on top of that....

That was what I was thinking, a few inches of papercrete to break the thermal bond, and then regular concrete on top of that, especially if using pex in a radiant floor heat situation.

The one problem I now see is the amount of cure time for aircrete, it takes about 2 days for it to get hard enough to even touch without making a dent, but I have a lot of research before I actually try this, Papercrete would be more solid but I think aircrete would have more  insulation value. Aircrete Harry, if you are familiar with him, has what he calls an epic mix that has styrofoam beads and paper in it but not sure of the exact mix he uses. He also puts baking soda in aircrete  to make it harder so I want to try that.Thank you all, Any input is welcome.

It is an interesting concept.

In terms of papercrete versus aircrete, I guess it just depends on how much insulation value is enough. I do not have the answer, but if say an R Factor of 4 is enough to stop the thermal bridge, it does not make sense to have an R Factor of 12. We learned this when I was a machinist. While we routinely worked down to .0001 of an inch, if the specifications called for a tolerance of only .010 then it was good enough.

Myself, I think the best concrete slab plan would be to go all out on the outside edge, say the first 6 feet, and get as much of an R Factor as possible, and then leave the center of the slab without insulation to let all that geothermal heat come up through.

But I did not do that, and I am getting good results so my guess is, the geothermal heat comes up through anyway. ???

Travis Johnson wrote:It is an interesting concept.

In terms of papercrete versus aircrete, I guess it just depends on how much insulation value is enough. I do not have the answer, but if say an R Factor of 4 is enough to stop the thermal bridge, it does not make sense to have an R Factor of 12. We learned this when I was a machinist. While we routinely worked down to .0001 of an inch, if the specifications called for a tolerance of only .010 then it was good enough.

Myself, I think the best concrete slab plan would be to go all out on the outside edge, say the first 6 feet, and get as much of an R Factor as possible, and then leave the center of the slab without insulation to let all that geothermal heat come up through.

But I did not do that, and I am getting good results so my guess is, the geothermal heat comes up through anyway. ???

Actually yes, you need to find out what the soil temp is at the depth your floor is.       The temp of the earth is constant   50 - 60 degrees in most locations ( depending on depth )   so your say 44 deg is reasonable.

Mart Hale wrote:

Travis Johnson wrote:It is an interesting concept.

In terms of papercrete versus aircrete, I guess it just depends on how much insulation value is enough. I do not have the answer, but if say an R Factor of 4 is enough to stop the thermal bridge, it does not make sense to have an R Factor of 12. We learned this when I was a machinist. While we routinely worked down to .0001 of an inch, if the specifications called for a tolerance of only .010 then it was good enough.

Myself, I think the best concrete slab plan would be to go all out on the outside edge, say the first 6 feet, and get as much of an R Factor as possible, and then leave the center of the slab without insulation to let all that geothermal heat come up through.

But I did not do that, and I am getting good results so my guess is, the geothermal heat comes up through anyway. ???

Actually yes, you need to find out what the soil temp is at the depth your floor is.       The temp of the earth is constant   50 - 60 degrees in most locations ( depending on depth )   so your say 44 deg is reasonable.

Yeah my soil temp here is always 57 degrees. But with a conventional home (not a WOFATI or something), I am going to get some cold infiltration into the unheated, unoccupied home. So to never have the temp go below 44 degrees was pretty good I thought. It says the home is super insulated, and enough heat is coming up through the floor to keep the home above freezing. It is not warm enough to be comfortable for living, but taking a home from 44 degrees to 70 degrees requires a lot less btu's then from 0 degrees to 70 degrees!