THE RETURN OF THE CORDWOOD HOUSE

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The Alberta Oil Sands Environmental Research Program (AOSERP) contracted with the Northern Housing Committee of the University of Manitoba to design and supervise the construction of a "stackwall" structure to house the 5,000-gallon potable water tank for the AOSERP research facility at Mildred Lake, Alberta. Most of the work was done by native people of the Fort McMurray area as a training project.

Construction was done during the cold weather of November and December 1975. The final outside dimensions of the building are 32 X 16 X 9 feet.

The stackwall method is to lay two-foot log lengths side by side, and mortar them in place to form a permanent log pile. Wood shavings are added between the log layers to improve the insulation. Logs of various diameters can be randomly placed, thereby eliminating waste of materials or time.

The advantages of the stackwall construction include:

[1] The high insulation value of correctly constructed walls lowers the overall operating costs of the building and equipment;

[2] The construction technique is labor intensive and thus a large percentage of expenditures can be channelled to man-hours as opposed to capital oriented machine-hours;

[3] The use, where possible, of indigenous materials reduces the capital output for materials.

The building was instrumented to determine heat retention and ease of heating. The insulating ability (or thermal resistance) of the structure was found to rate at least R18, which is about equivalent to a 6"- thick glass or mineral fiber insulation batt.

The total cost was $10,960.20 which included $6,685.85 for labor. Thus, if a person built it on his own during warmer weather the cost would be very low.

LOG GATHERING, CUTTING, AND SORTING

The collection of the necessary logs started 28 October 1975 with a crew of three men. The logs-a variety of spruce, poplar, and pine-had been cut and piled for approximately three years. They were located 12 miles from the construction site and were transported in a 3/4-ton truck with a load capacity of about 0.75 cords.

The cutting and sorting began while collecting and transporting continued. The crew was increased to four men, two collecting and two cutting. This procedure, using recorded man-hour data, required 38.6 man-hours per cord. It includes the time involved in construction of a suitable jig to enable more accurate cutting of logs with available handheld chain saws. The tolerance, measured by random sampling, was 1/2". Lags within the range 23-3/4" to 24-1/4" were accepted, all others discarded. Also cut were the "sawn three sides" 8 X 8's. They were ripped at a nearby sawmill and delivered to the construction site in 12foot lengths. For construction purposes, they were cut into 30" lengths and used as corner blocks (discussed later).

In total, 10.6 cords of logs and 288 lineal feet of 8 X 8's were cut, costing a total of $1,706. In terms of price per cord of wood used in construction, the figure would be $160 per cord, and in terms of price per square foot of wall area (materials only, no labor), the figure would be $1.71. The labor-to-material cost ratio is 1.7:1.

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