Page 25 - Maryland Historical Trust - Archaeology Colonial MD

By supporting the entire structure on posts, expensive masonry foundations were eliminated. It employed the most abundant construction material — wood — and the housewrights quickly began selecting or devising less labor-intensive methods of construction. The few surviving buildings from the 1600s in the Chesapeake show that mortise and tenon joints were only used for major timbers. For most others, simple lap joints assembled with nails were relied upon. This cut the labor costs sig-
nificantly. The walls and roofs were covered by thin five foot long sheets of riven oak called clapboard. Chimneys were frequently built of readily available wattle and daub. Earthfast construction was a me- dieval British architectural practice that had fallen into disuse as English forests were cut down and timber became less available. But it was well suited to the tree covered setting of early America and saw a rapid revival.These early colonial houses with earthfast foundations and walls and roofs made of
and the later Baltimore County Orphans Court6, puncheon construction was used mainly for expedient buildings and also rapidly declined in use.
Sill-on-ground construction entailed placing continuous timber sills directly on the ground, or sometimes in a shallow trench. These sills would then be framed together at the corners
and bents (see figure C) or framing studs attached to form the walls of
the building. Such structures are very difficult to identify archaeologically.
If the sill was laid in a shallow trench, portions of it may be preserved to provide the archaeologist with an indication of the building’s size, but more often than not the trench is either destroyed by plowing or was never present in the first place. Frequently
a sill-on-ground structure will be identified by the presence of internal cellars, subfloor pits, chimney falls, or other features that indicate a building was once present. Ground-laid sill buildings were a predominant form of architecture during the third quarter of the 17th century.7
Sill-on-block structures utilized
the same basic form as sill-on-ground structures, but the building was elevated on wooden blocks. This protected the continuous sill on which the framing members rested, and the support blocks could be easily replaced when decay
or insect damage got the better of them.8 The main disadvantage of such
a structure was that the gap between the sill and the ground surface meant
a simple packed earth floor could no longer be used. A more expensive plank wood floor would be required. Again, unless chimney remnants, shallow holes for the supporting blocks, or storage pits were present within the footprint of the building these structures leave few traces archaeologically.
Finally, post-in-the ground or hole-set framed buildings provided a compromise between structural stability, and ease of construction and repair.
For these reasons they proved to be
a popular design choice. Post-in-the- ground buildings used an interrupted sill (see opposite page), but with support posts (preferably of durable woods like black locust or cedar) sunk into the earth at regular intervals. One common method of construction was to assemble a structure called a “bent” consisting
of two opposing support posts and a joining tie beam or ceiling joist on the ground. Postholes would then be dug and the bents raised into an upright position (see figure C). Interrupted sills could then be joined to the upright posts and framing studs installed atop the sill and between posts. Another alternative was to build the sidewall of the building, consisting of the support posts and an upper wall plate. Then both sidewalls could be raised, sill plates installed, etc. Interestingly, these two methods lead to unique archaeological signatures. Sidewall construction
results in a building footprint whereby postholes with molds are arranged in parallel lines of rectilinear post holes
figure C
Raising a “bent” for a post-in-ground structure.
with their long axes perpendicular to the long axis of the building. Conversely, bent-assembled buildings will have parallel lines of postholes with their long axes in-line with the long axis of the building.9 Post-in-the-ground structures were not immune to termite damage and decay, but the added stability of durable sills and posts meant that one or the other could be replaced when necessary without sacrificing the overall structure’s integrity. Indeed, archival evidence and archaeology both suggest that frequent repairs were needed
to maintain these common earthfast structures.10
Earthfast construction gradually began to be replaced in the Chesapeake with more durable forms of architecture during the 18th century, especially for main dwellings. By the Civil War era, most earthfast forms were predominantly being used only for outbuildings, quarters, and more temporary structures.
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