Toronto — Du Pont Canada thought up the idea more than a dozen years ago as a way to sell more of its quality foam insulation. Pan-Brick Inc. recognized it as a great way to provide a building with the beauty and durability of a brick-finished exterior and high energy-efficiency at one and the same time.
The product, now being manufactured in the Canadian province of Saskatchewan and soon to be produced under license in several other areas of North America, is an easy-to-install brick-faced sheathing with an R value of 8.7 (compared with 1.2 for conventional brick veneer).
It was introduced to the construction industry at the January convention of the National Association of Home Builders in Houston and most recently at the New Neighborhood Forum here in Toronto.
Pan-Brick, as the product is called, is a panel made up of half-inch-thick kiln-fired clay brick slices imbedded in 11/2 inches of polyurethane foam insulation and backed by plywood sheathing.
Each panel interlocks at the sides (somewhat like a jigsaw puzzle), has tongue-and-groove edges, top and bottom, and is screwed to the stud wall which may be either wood or metal.
Each panel is 4 feet wide by 16 inches deep and weighs a mere 35 pounds. This calculates out to some 3 tons for an average three-bedroom home compared with 18 tons for one with a full-brick exterior.
When attached to a conventional 4-inch stud wall, filled with R-12 batts, with a drywall interior, the R-factor of the wall totals a respectable 22. The fact that the polyurethane sheathing core enfolds the building without any breaks means that heat leaks through the studs are effectively eliminated.
Other pluses for the Pan-Brick panel:
* With minimum training a semiskilled workman can lay out and fasten the panels.
* The panels are put on dry, no sealants being necessary nor are fasteners visible after installation.
* Cold weather is no hindrance to the installation. As a general rule a Pan-Brick wall should come in at 20 percent under the cost of a conventional brick wall while providing vastly more resistance to heat loss.
Between 1969 and 1973 Du Pont Canada researched and developed the panel, eventually applying it to more than 400 buildings in 13 centers in Ontario.
Ken Sexton, owner of Pan-Brick, says he became sold on the product after viewing several hundred buildings. They had a ''true-brick look'' and had retained their ''like-new appearance after 10 years of weathering,'' so he bought the patents from Du Pont ''right down to the filing cabinets.''
As part of the deal several Du Pont researchers helped in the start-up of the Regina, Saskatchewan, plant.
Some refining of the manufacturing method has since taken place and Pan-Brick is now ready to license other manufacturers. Ultimately, Mr. Sexton sees seven plants in Canada and perhaps 20 in the United States as the ideal. Overseas licensing is also planned.
While only a fraction of the weight of conventional brick, the product is heavy enough to make long-distance hauling a significant cost factor, hence the need for regional manafacturing plants.
Because the bricks are set into the polyurethane while it is still in raw form, the chemical reaction is tremendous, providing an iron-tight bond. No adhesives are needed.
* More than 700 pounds of force is needed to tear an individual brick slice from the foam core.
* High freeze-thaw resistance. No effect after 200 cycles from 80 degrees F. to minus 20 degrees F.
* No water penetration after 20 minutes exposure to direct water spray at 70 gallons a minute and a pressure of 70 pounds per square inch.
* No degradation after 7,000 hours of exposure to ultraviolet light and water.
* The mortar joints are puncture resistant to 900 pounds per square inch.
For more information write to Pan-Brick, 610 Henderson Drive, Regina, Saskatchewan S4N 5X3, Canada.