Harry,
I have spoken to the president of Airkrete wall insulation where they use Magnesium Oxide cement. I tried to make a portland based foam concrete as stiff as shaving creme to use as insulation but was unsuccessful. It is always a very runny mixture. I am interested what your results were with the Magnesium Oxide Cement and did you have a mixture that could be used to fill a wall cavity for insulation? Where did you buy the Magnesium Cement and how much did it cost? Thanks
Stephen Williams

Hello, I have been experimenting with a Portland based foam airkrete mix super light to see if I can come up with a mix that will work like Airkrete. I spoke with the inventor of airkrete and yes they are using Magnesium OxyChloride as the base, mixing in calcium chloride (road salt)which acts as an accelerator, talc powder as a filler, magnesium hydroxide, and a proprietary chemical. They are able to generate it down to 2.5 lbs/cu ft. And it is stiff enough to hold it's shape. Mgo is 10 times the cost of Portland though. You can get it from Premier, the only Mgo mine in the US. He said the raw materials cost 18 cents per board foot (12x12x1). So $2.16/cu ft or $58.32/yard when placed in the wall. Installers charge 70 to 90 cents per board ft installed. That gets pricey. It is a great insulation and with his new patented foaming gun they have gotten up to an R6 per inch. They were at R3.9 per inch prior to the foam improvement. I read the patent on the gun and they are using a 2 stage process where they pass the foam through tightly packed glass beads. They then go through a size 20 mesh screen, have a little gap and go through a final 30 mesh size screen (30 holes per inch). This is a very fine mesh but it creates a very fine uniform bubble foam which is much stronger and has much better insulating properties. I have bought some of this mesh to experiment with. I am getting down to around a 10 lb/cu ft mix so far but the mix slumps and will not stay in a wall without a form to hold it. If I try lighter mixes it is collapsing on me as it dries and is worthless. A company called Allied Foam Tech has a mix that is very stiff and can fill an open wall without slumping out. I found out they are adding an epoxy to the mix and it is a pricey concrete mix. I am trying mixing some inexpensive glues to the foam water and getting some stronger bubbles. I have some Calcium Chloride on the way to try accelerating the cure. I will keep you posted how it works. Stephen

Hi All, I just got my gallon of Drexel FM 160 foam agent. I have been experimenting with Ivory Dish liquid and 2x Dollar General concentrate. I got some good looking solid blocks with the Ivory. The Dollar General 2x concentrate made good looking foam but it evaporated quickly and I got horrible crumbly concrete out of it. This Drexel foam makes beautiful rich foam and it lasts a LONG time on the ground. I can tell a difference how it mixes with the concrete. It looks like I will get great block out of it. Stephen

Hello, I wanted to know if you could pour aircrete about 4 inches thick up around the outside of the footings to insulate it for a monolithic concrete floor pour? Can you backfill up against this without any sealing or do I need to seal the aircrete for moisture below grade? This would be a better solution than rigid foam board as is commonly used if it will work. Thanks Stephen

Thanks Hajjar. Is it necessary to use fiber reinforcement in the floor pour? I have been told that fiber in the concrete is stronger than laying wire mesh in the concrete. I am wanting to prevent cracking.

Hello, I am wanting to pour an aircrete floor for the house, porches, garage, and driveway. How do you finish the surface of this pour? I am assuming it needs a hard finish coat of some kind. Does the aircrete pour need reinforcing? Does the surface coat need reinforcing with something? Thank you for your help. I have learned a tremendous amount from watching the videos and reading the discussions.
Stephen