Although yurts are considerably lighter than conventional houses, there still is considerable weight to the materials, and the proper support structures need to be in place.
Many yurts are built as elevated structures, either in total or in part, since many are built in locations with considerable slopes. There is a tendency to construct these units on simple 4*4 stilts, with little regard to lateral rigidity. Additionally, when yurts are built on platforms or raised decks, they alter the wind flow in, around and under the building. This practice also exacerbates drainage and snow build-up issues, as moisture tends to flow more freely under the building.
The primary consideration should be to structural integrity. Merely walking on a platform or deck that is held up by 4*4 posts causes the building to vibrate. Like the harmonic effect of a bridge structure swaying in the wind (or a child’s swing being propelled on larger and larger arcs), this rhythmic motion can increase in intensity, causing the supports to break loose over time. Cross supports should be used, in addition to ties to hold the structure caps tightly to joists or beams. Ensure that you have placed a sufficient number of stilts along the length and breadth of the platform, to prevent sag.
Wind flow can be a very serious concern for yurt design. A moderate wind, funnelled beneath the yurt, may billow, like the air beneath a parachute canopy. This air flow has a detrimental effect on heating & cooling, as well. Yurts are designed to allow for easy air flow around and over the structure, and were never designed to allow for air flow beneath.
The third concern is moisture redirection. Allowing snow load to build up under your yurt will result in high moisture content in the spring, and the contingent possible decay or mould formation on the underside of the structure. Allowing water and snow melt to drain freely under the platform, as well, will contribute to the undermining of the earthen base on which deck posts rest. This, in turn, decreases structural integrity. You should install a water redirection system on the upper edge of the yurt platform, and redirecting barriers in a lead position on each deck support leg. This will minimize the risk of water erosion.
Just because yurts are considered as an “alternative” to conventional housing does not imply that improper or inadequate construction techniques should be employed. Care in design, construction and maintenance of your yurt supporting network is a critical to building integrity as it is in conventional housing.