This Instructable includes complete step-by-step instructions on how to make an insulated earthbag foundation. You can use the same process to make insulated foundations for any type of structure – straw bale, earthbag, cordwood, etc.
Yurts or gers are very efficient and practical in harsh, cold climates, as evidenced by centuries of use in Mongolia. Benefits of yurts include affordability, rapid construction, ease of construction, wind resistance, great looks and portability (ability to take your home with you if you ever move). You may even save on taxes since some jurisdictions do not consider yurts permanent homes.
Many people build their yurts on a raised wooden platform to reduce moisture problems. But wood is expensive and building a platform/deck requires a fair amount of tools and carpentry know-how. Wood is vulnerable to fires and prone to rot and insect damage. It also requires regular painting or sealing.
In addition to the many other uses for earthbags, you can build insulated foundations by filling the bags with insulation such as scoria. The benefits of the insulated earthbag foundation system described here include:
– Very low cost, especially if you can locate recycled grain bags from farmers
– Very simple construction using just a few tools most people already have
– Save energy and enjoy a more comfortable home because the floor and foundation are superinsulated (plus, there’s no wind blowing under the floor to suck heat away)
– No deep footings/excavation required (research Frost-protected Foundations for technical details if you’re interested)
– The finished floor can be raised above grade as high as necessary (Deep snow? Flooding? No problem.)
3D AutoCAD drawings show each step of construction.
You might want to follow the Earth-Sheltered Solar Canadian blog, who’s planning to build an insulated earthbag foundation that’s suitable for extremely cold climates. It’s the same process as outlined in this Instructable, but they will use a deeper trench with insulated earthbags below grade to create a Frost-protected Shallow Foundation (FPSF). Combine these two ideas – FPSF and insulated earthbag foundations as shown in this Instructable – and you’ll have everything you need to know for free.
You can read the complete Insulated Earthbag Foundations for Yurts article by Owen Geiger at Instructables.com.