Dear Waterstar, Yes, I agree it is confusing! It took me many readings of Sunny John's site to understand how it works. I am not sure about the foundation. I think it is possible to excavate, install the tubing and then backfill the ground flat enough to put the greenhouse on brick but you probably need to mechanically compact the soil. You should insulate the heat sink around the perimeter to protect your heat from being siphoned away by the frost layer. About clay soils Sunny John says, "Our experience shows that heavier subsoils continue to act as good heat sinks if the tubing has 6" of subsoil above it (8" OC from the surface) You should go deeper if your soil mass is lower." Whether on not it makes sense for your greenhouse, I don't know. It seems to me that your greenhouse is a little small for this system but I have heard of people using SHCS in a small greenhouse and being happy with it. Sunny John did say that having the tubes at least 30 feet in length is optimal. For the greenhouse I am building it will only be 20 feet and I am using stone for the storage medium. I would not worry too much about soil/clay getting into the tubes unless you are in an area with a high water table. If you are, I would use stone because then the water can come in and out without bringing in any mud. Contact David Roper. He is wonderfully helpful!

kathi- There are some homes on the bay in Appalachicola, Florida (a/k/a near ground zero in hurricane activity) that are made out of a modular concrete coated styrofoam. They were built in the last 5 years, so I know they meet current code. I do not know what the product is called, but it seems that an architect or structural engineer in the area that you will be building should be able to easily ascertain the modular products that meet local code requirements.

Charannthom, you can find all sorts of discussions and "experts" describing what it costs to build in Texas, Ecuador or anywhere in the world. None of these have much meaning, since they don't apply to you, your needs and wants, your property costs and the applicable building regulations, cost to improve your property, the price of materials and labor, the extent to which local builders are busy or slack, availability of skilled labor, and a host of other things over which you have no control. Only a builder with current local-area building experience knows about these key pricing issues on a local level. Regional differences are often enough to make or break a construction budget. And then there are the funds needed for "contingencies" and the "oops" that happen in almost every project. Thus, "regional averages" won't help much. Trying to budget by using regional average cost/SF numbers from other projects is probably construction roulette--spin the wheel and take your chances! The only way you will know what it costs to build where you wish is to get a detailed, written contract from one or more builders that's binding for at least 30-60 days. Verbal comments, "estimates" and averages are not worth your time, since they aren't binding, and you have little knowledge about the specific circumstances which comprise the averages. Your best bet may be to look for recently built homes similar to the one you have in mind and find out their finished cost. Look for recently completed homes similar to your ideas and find out what it took in time and dollars. Your other "best" option may be to take completed construction documents to several builders you trust and ask for a written estimate and owner-builder contract. Every builder's contract is different, and you may be surprised at what's included (or omitted) from the terms and conditions of one builder versus another. Don't be surprised if one or more builders asks for a deposit or to be paid for the time it takes to prepare a detailed estimate. Their time is money to them. You give the impression that you have strong opinions about your situation and proposed project. If so, I strongly suggest you do your full due diligence and not rely on "regional averages" or some thread from this or other Internet-based forum. Good luck on your project. This post was edited by virgilcarter on Sun, Oct 26, 14 at 17:15

Nursetammi: Yes - it's the same as the rule of 6 & 10 - here's an example: Let's say that you have 2CM stone and you want an 18 inch deep overhang - you'll need to have at least 12 inches of the total span supported by either a corbel or a Counterbalance Plate from Chemical Concepts. here's another example: Let's say you'd want a 15 inch overhang span and your stone is 3CM - in this case, you'd need to have at least 5 inches of this total span be supported by a corbel or a Chemical Concepts Counterbalance plate - so that no more than 10 inches of the total span is un-supported. Dos that make sense? Just remember that the amount of unsupported span of the stone depends on the thickness of the material - 2CM means no more than 6 inches can be unsupported of the total span, and 3CM means that 6 inches of the total span can be unsupported. Also - remember that 2CM stone should ALWAYS have a sub-top of 5/8" PLYWOOD - preferably ACX (sanded one side). IMHO - Marine grade plywood is overkill - unless the assembly is going to get wet much of the time. Plywood - in and of itself - does not add structural rigidity to an overhang - it provides support when installed over cabinetry, but plywood WILL flex in an overhang application if not supported by corbels, structure or counterbalance plates.... hope that helps ya kevin