This is the second article on building a solid wall yurt.
Although yurts both are vastly lighter in weight than conventional housing and offer minimal wind resistance, they, like any house, still require solid piles on which to rest.
There are a number of options available to provide a solid base for your yurt, with the simplest and most solid being beams on pad, with no posts and no piles.
When you opt to construct a solid wall yurt, rather than tarpaulin and lattice, you add significant weight to the structure, but, through the use of innovative top and bottom plates, cable reinforcement, hurricane ties and mending plates on the walls, you can build a yurt that equals any house for structural integrity.
To design a base system for a yurt by boring piles is an illustration of overkill, however. Not only do you change the definition of your building for zoning and permitting purposes, you provide a degree of reinforcement that is quite unnecessary.
The most cost effective and structurally sound combination of bases for your yurt is a simple pad system. However, you may, depending upon the grade and type of soil, need to use posts and pads, notched pads, crossties and webbing, saddle brackets and so on.
Let us look at the most simple design: beam on pad. Whereas conventional wood frame homes may require 2 by 12, 2 by 10 or doubled versions of each for beams, imbedded joists, grade beams, piles, etc., yurts, even as large as forty-two feet in diameter, will require no more than single 2 by 10 or 2 by 8 beams under 2 by 8 or 2 by 6 joists. For flat terrain with packed soil and good drainage (or in high wind regions), use a basic patio pad. For sloped ground, gravelly or soft soil or windy regions, use notched pads, or notched pads on patio pads secured with anchor bolts.
Begin by ensuring that all pads are level with each other. Simply lay the beam into or onto the pad, and then tie the joists into position, sixteen inch on centre separation. Beams should be spaced a minimum of eight feet apart, with pads spaced four feet apart for greatest stability. Reinforce the beams by nailing cross supports between beams at eight foot separation. As in conventional housing, joists should be tied together with webbing (2 by 2s).
To use post and pad on heights not exceeding twenty-four inches, use four by four double saddle brackets and double the beam using a second eighteen inch length of beam material in the upper saddle bracket. Set the foot of your four by four pile into a slotted deck pad, ensuring that the top of each four by four posts is level versus each other post top.
To use post and pad systems on heights exceeding two feet, be sure to use diagonal cross supports extending from the bottom of each post to a nearby beam or joist on two adjacent sides, alternating sides with each sequential post location.
After laying the joists into place on the beams, be sure to install appropriate headers, using a minimum of four 3.5 inch nails per joist-to-header connection, and three nails, toe-nailed into place on each beam intersection.
Since you already have ensured that the structure is level (by levelling either the pads or the tops of the posts), you should only need to check level of the joists to ensure that nothing has shifted during construction. Now, lay your underlay into place, using 2.5 inch nails. The tongue-and-grove ¾ inch OSB or plywood should be placed so that edges meet at the centre of the joist. Use plywood ties between joists for added structural strength. Your next layer of flooring will be installed at right angles to the underlay, at a later time.