db71 wrote:I am on a very small budget but I have land with lots of rocks in se oklahoma. Due to our economy we are planning to build there and sell our current home in texas. Any info on this type of building design is greatly appreciated. What are the insulating material options? What is most cost effective?
Pictures tell the story, unfortunately I lost many of my slipform pictures in a lightning strike.
For wall insulation, I used 2" white styrofoam sandwiched between the two layers of slipform rock. I'm extremely pleased with the final product, but have to say that the work was very slow and physically demanding at every step of the way. That's why I only went up 5 feet with rock. Construction got more difficult as the height increased and I had to carry rocks and buckets of concrete up a ladder.
But the rock portion of the wall will last forever, there are absolutely no air leaks, it looks great, and it's cool in the summer and warm in the winter.
My 16" thickness was only needed because it was supporting a 16" thick cordwood wall above. Otherwise 10" would prolly be plenty for a single story wall.
Budget wise, IMHO you don't save much with rock or cordwood or any other unconventional building materials. Even if the walls are free, most of the total cost of the house is in stuff other than the walls -- the foundation, windows, rafters, roof, ceiling insulation, electrical, interior, etc.. The foundation footings have to be more substantial to support a rock wall so that actually increases the cost. Framing the windows and doors requires quite a bit more lumber for this type of construction because the walls are thicker, so that increases the cost. Electrical has to be imbedded in the rock wall so that increases the cost and difficulty. It takes much longer to build, so that increases the cost and inconvenience.
If your main goal is to save money, I would go with stud wall construction and a fire resistant 4x8 siding (like some of the concrete board products) on the outside, and drywall on the inside. I doubt if you could get a manufactured home up your so-called "road," otherwise that would be an economical option.
Like you, I was interested in alternative construction materials because they are "free," or nearly so, but bear in mind that they take much
longer to build and it doesn't save that much money overall. If you like the look, and if money and time are no object, then knock yourself out. If time and money are limited, it's hard to beat stud wall construction.