Wow...this may just be what I was looking for!! I want to build an underground house and have been trying to figure out the best method with cost included. I love the AAC products but they are not meant for below grade. I am going to seriously consider this.

Ed Ryan, who started Ryan Homes, asked me to build 2 houses using the AAC block back in the early 90s. He had sold his company to NVR and retired to FL where it had just been devastated by a hurricane. He wanted a safer product that would withstand that event in the future and decided to do 2 test houses in FL and 2 in the northern climates. He visited this original AAC plant in Germany and had enough block shipped in to build four houses. Since everything here in this area is high side or low side, some portion of the foundation must be buried unlike FL where foundations are not even used. Therefore we used traditional block for those below grade areas and the AAC block for the rest of the home. I totally understand the silence!! It was like being in a tomb until we sheet rocked and trimmed. These two houses were monitored for a year before I was to sell them. They were full of technology ahead of that time to send all data to Ed in Florida. It turned out that the houses used less than 25% of the utilities a typical house used. I will add that the mason...after struggling with the fact of using over sized block...loved working with the light blocks! The mechanical contractors spent a bit of time on the first house until they figured out how to properly groove out the areas they needed but it went well. We applied the sheet rock directly to the block and never encountered a crack over the entire first year. I do not know what happened after that but I would think it would be sturdier than any wood could ever be.

I know the test houses were so successful that Ed started two building companies in FL that only use the AAC materials and my understanding is they withstand hurricanes and such just fine. I went to see them once after they were built but have not returned. They were the identical floor plan that I had to use and totally out of place in FL!!

I visited the Georgia AAC plant last year with the intent to build the next couple of hotels with it. Even with the shipping costs from there to PA, it is a savings of over $500,000 from steel/concrete or even wood framing and a much superior product. Thank you for posting the ICF info. I am off on this new quest as soon as the garden is finished! Very exciting stuff!

Yes, these forms are very light. One form is 4' long and 2' tall and they come in 6,8,or 12" widths. So, one ICF form will take up the area of 6 concrete blocks. The blocks (8" wide) weigh 30 lbs apiece or 180 pounds while a ICF of the same area weighs around 3 pounds. That is why they can be stacked so fast. The savings in time and labor is amazing not to mention the wear and tear on your body. You don't have to kill the crew on this job. In the spec sheet for Polysteel they claim that their wall system will bounce a 50 cal bullet! Running sewer and DWV pipes is a piece of cake, you just cut a hole through the forms with a pointed drywall saw and use touch and seal spray foam in a can to fill any miscuts or voids. To run romex on the inside you use a hand held gun type hot knife to slice a trough into the styrofoam to place the wires into. Same with the electrical boxes. The forms come with a galvanized nailer spaced every 16" so screwing drywall to the interior is just like over wood or steel studs. The 2by frames for the windows --on the bottom of the frame you use 2 -2x4s which allows an opening to pump the concrete through. We drilled holes through the wood frames and ran 5/8" hot dipped galvanized carriage bolts through the wood frames to secure them into the concrete. Super strong. I was impressed with the finished product. The forms act as a sound barrier as well as insulation and once you stepped inside, all exterior noise could not be heard, wind, overhead aircraft noise etc was nonexistent. We left 5/8" bolts sticking up out of the top of the walls to bolt down a mudsill to attach the rafters/truss system to. Then we used Simpson Strong Tie truss cups to bolt the trusses down so no windstorm can ever pull the roof off. He used hardy board for exterior siding and it looks real nice. This cement hardy board combined with a standing seam blind nailed metalic roof makes a fireproof house and thats what you need in the wild wild west. Ceiling insulation was R-40 foil faced rigid insulation. He use to brag that he built a fire in the wood stove on Thanksgiving Day and then another one on Superbowl Sunday to heat the house for the winter. :D This was a mountainside , in the hill type of house where one side was buried into the hill. I applied 2 coats of DryVit Primus acrylic cement waterproofing material over the exterior of the ICF walls where they were functioning as a retaining wall to act as a waterproofing agent. After it dried we set 4x8 sheets of soundboard up against the walls to act as a buffer to protect the walls when we backfilled them. So far there are no leaks.

Thanks Toepopper!! I was not aware of this process for subgrade use! I have used the AAC block and panels in construction for almost 20 years and have often wondered why a way to use it in foundations wasn't being looked into. Is the ICF a much lighter product too? I know AAC products have a R55 insulation factor and easy to work with running mechanicals, etc.

I have been watching the developement and acceptance by the building industry of insulated concrete forms. At the time I first saw these new forms I thought they would be just another fad in the building trades and considered them an inferior product that could not withstand the rigors of seasonal weather changes. I asked myself who in their right mind would build a home out of styrofoam? Then a friend retired from American Airlines and wanted to build a house using the Polysteel insulated concrete form system which was one of the first companies to manufacture these forms. At the time, 2001, work was slow so I hired on to construct the concrete foundation for the building using traditional wood forms and rebar supports protruding up out of the foundation walls. These vertical rebar uprights would go inside the Polysteel forms once the foundation concrete was dry. We poured the concrete foundation and I stood back to watch my friend and his daughter stack styrofoam forms and tie rebar in place over every row. The doorways and windows had to have a wooden frame built to allow for the appropriate sized opening. It took them only 3 days to stack the forms and tie all the rebar in place. He installed some vertical 2x6 corner braces on the corners to hold them plumb while pumping concrete into the forms. We pumped the walls up with concrete at 3 foot intervals dragging the pump hose around the perimeter 3 times so as not to put too much pressure on the forms. These forms have an insulation value of R-40. This house continued with a second story so the walls were a total of 16 feet high. I was impressed with the forms, the speed in which this house was built and the quality and sense of permanence the finished product had. The forms remain in place and act as the insulation and you can attach wood siding, brick, stucco or cedar shakes onto the outside of the walls and use regular drywall on the interior. The house was so well insulated that he only used one cord of wood to heat the place during the winter. Since that time there have been many more producers of insulated concrete forms with different types of systems and the cost has come down during this depression. These units may be used below grade for a basement or cellar and have been approved by all building codes. There is much information to read on the internet, just type in ICF and read about all the different types of forms being produced.