Reconstruction of a "Virginia House", the Godiah Spray Tenant House, at Historic St Mary's City, Maryland.
The Spray House was modeled on the 1662 - 1667 records of Robert Cole's plantation at St. Clement's Manor. It is an 18 feet by 20 feet, post-in-the-ground dwelling with dirt floors and a clay chimney, or so called Welsh chimney.
Typical of the Virginia House, the sides and roof are covered with oak or chestnut riven clapboards. Although difficult to see in this photo, the roof rafters are supported by tie beams, a special type of joist which extended beyond the wall lines.
Figure 1 from Garry Wheeler Stone, "The Roof Leaked, But the Price Was Right", Maryland Historical Magazine, Vol. 99, No. 3, 314. 
In the above photo of the re-construction of a Virginia House, you can appreciate the large, hole-set corner posts with intervening hole-set vertical studs. The joists, so called "tie beams", extend beyond the walls to support the "false plate" over which the roof rafters are lapped near their bottoms. Half way up, each pair of opposing rafters are connected by "collar beams" which provide structural support. Collar beams were a characteristic eighteenth century refinement.
In "The Roof Leaked, But the Price Was Right", Garry Wheeler Stone discribed three stages in the development of the Virginia House:
"The first, substitution and selection, dates from the arrival of the first settlers in 1607 until about 1650. During this stage, immigrant carpenters discovered which European building practices and Chesapeake materials were best suited to withstand North American termites and thunderstorms.
During the second stage, evolution, dating roughly from 1650 - 1675, the Chesapeake carpenters....developed the basic structure illustrated in Figure 1. The massive wall posts gave the structure some termite resistence, while the light 2 in. by 4 in. scantling and riven (hand-split) boards permitted rapid nailing together of the remaining building....
During the stage of refinement, 1675 - 1725, frontier pressures slowly eased and carpenters and their clients began to be concerned with the longevity of their structures. Increasingly, they selected rot-resistant wood for their wall posts and sills; and joints were refined for strength and ease of assembly. The Virginia House continued to evolve after 1725, but no longer as a frontier structure." [353 ]
If you came to this webpage directly, you may read more about the innovation of Virginia House here (link) .