Plank House

The plank house is the traditional large dwelling of the Indigenous peoples of the Pacific Northwest coast of North America, from northern California through Oregon, Washington and British Columbia to south-east Alaska. It is a post-and-beam building clad on its walls and roof with wide planks split from cedar, often housing several families.

Roof forms

Two main forms are described:

• Gable roof: paired ridgepoles carry roof planks sloping both ways, over vertical plank walls; some houses had an interior pit reached by steps. Chinookan houses on the lower Columbia River were gabled, with doors usually in the gable end.
• Shed roof: a single-pitch roof, described by James Cook on Vancouver Island and around Puget Sound; these were among the largest houses of the region. Accounts suggest the pitch was set according to the direction of the rain, regionally from the south.

Planks

Western red cedar, with its straight grain and natural weather resistance, was the preferred wood in south-western Canada, Washington, Oregon and northern California; further north in Alaska, spruce was more often used. Planks were split from logs or even from standing trees with wedges and finished with an adze. Simon Fraser, descending the Fraser River in 1808, noted planks 3-4 in (7.6-10 cm) thick.

Roof and wall planks were tied to the frame with cedar withes or cordage rather than nailed, so a household could move them between frames in summer and winter villages and leave the frames standing. Planks were sometimes sunk in ponds, probably to kill vermin and keep them from drying and splitting.

Size and lifespan

Lower Columbia houses ranged from about 30 ft to more than 400 ft (9-120 m) long and were commonly 15-30 ft (4.6-9 m) wide. The house at the Meier site near Scappoose, Oregon, measured about 55 by 90 ft (17 by 27 m); one at Cathlapotle, Washington, was 33 by 185 ft (10 by 56 m). A house could remain in use for 400 years or more, but roof planks needed replacing every few years and posts about once a decade; maintaining the Meier house over its life is estimated to have taken 700-1,400 trees. Fraser also described a house with walls 11 ft (3.4 m) high under a slanting roof.

Age

Basic plank-house features on the lower Columbia are at least 2,000 years old, with the oldest houses there dated to about 2,200-2,500 years ago. The Paul Mason site at Kitselas Canyon, British Columbia, is about 3,000 years old, a rectangular building at the Maurer site dates to 2830-1920 BCE, and a rectangular structure in northern British Columbia about 7,000 years old is, according to the Oregon Encyclopedia, the oldest known on the coast.

Peoples

Plank houses were built by many nations, including the Coast Salish, Quinault, Chinookan peoples, Kwakwaka'wakw and Tlingit.