The Shingle
Equal parts function and recognizable form
BY PETER B. BRACE INDEPENDENT WRITER

ROB BENCHLEY/The Independent

Part 2 of 2

Maibec, headquartered in Sainte-Foy, Quebec, Canada, produces 300,000 squares of Eastern white cedar shingles annually, selling an estimated 7,000 squares on Nantucket last year. Wood shingles are sold in squares, with four bundles of shingles in each square totaling 100 square feet of wall coverage.

They begin as Eastern white cedar, coniferous trees found in swamps growing no more than 100 feet tall but living as long as 1,000 years. Also known as Eastern arborvitae, American arborvitae, Techny arborvitae and Northern white cedar, Maibec's Eastern white cedar trees are harvested predominantly in Aroostock County, the top portion of Maine.

Twenty-five percent of Maibec's trees come from forests certified by the Forest Stewardship Council, a sustainable forest group that sprouted from the 1992 Earth Summit in Rio de Janeiro to guide forest management worldwide. Maibec is the only such seller of Eastern white cedar shingles in the world.

Once harvested the trees are hauled to Maibec's four mills, debarked and cut into 16-inch blocks, which are then distributed to the 15 sawyers in each mill. The sawyers each operate several machines, which slice the blocks into rough shingles and trim their edges before they are fed into another cutting machine that re-squares each shingle so its sides are parallel with each other and re-butts them so each shingle's bottom edge is straight and square. From this machine, the shingles are packaged into 25- square-foot bundles for shipping.

Most sidewall shingles are sold in three grades rated for quality, the highest being clear of any knots and other defects, the next having no knots on the exposed face and the lowest quality being replete with knots. Maibec's three white cedar sidewall shingles grades are sold as place names to distinguish their quality from each other for the purpose of name recognition.

"Obviously, 'Nantucket' was our area for top of the grade," said Maibec sales representative Keith Ball. "We call them 'Extra.' The next grade is called a 'Clear' and that's the 'Kennebunk.' The 'Nantucket' is clear of knots. The 'Kennebunks' are allowed knots six inches above the butt. The 'Bar Harbor' is called a 'Second Clear' and you're allowed to have defects on the exposed face, but not open knots."

Naturally, Nantucket-model shingles are the most expensive at $200 a square; Bar Harbor is the cheapest at $90 a square and the Kennebunk is somewhere in between, said Ball.

Builders on Martha's Vineyard seem to prefer Maibec shingles treated with Cabot's bleaching oil, which accelerates the weathered aging process to three years.

SUN, WIND AND SALT

"It's an amazing piece of wood," Ball said. "It does not rot; it just wears away. The mold, mildew and moss - that stuff eats away at the wood fibers and it definitely wears away faster, but the wood, because of the tannic acid, it does not rot."

It does not rot because it is a naturally rot-resistant tree species, said preservation carpenter Michael Burrie.

"Different trees have different degrees of rot resistance depending where they grow," he said. "They're called extractives and the tree puts them in the heartwood inside to preserve it. I've seen hundred-year-old shingles that are in reasonably good condition."

Ball said the life of the White cedar shingle depends on its application to a building. If installed properly, with the right drainage and ventilation, he believes these shingles can last 30-40 years.

Certainly proper shingling techniques are key to making the shingles last and keeping the building dry. Along with the Nantucket carpenters who want to throw up more than the island standard of one square per person per day, operating on the time-is-money premise, there are equal numbers working at quality control.

One such builder instructed this reporter during his five-year stint as a carpenter to nail his shingles upwards of the five-inch mark of the exposed face so the nail heads did not show, keeping his shingles tight to each other and squared in place. Varying the widths of the shingles was key, as was allowing no less than an inch of each shingle to horizontally overlap the ones below it in order to prevent water seeping in.

The bottoms of windows were of particular concern for this builder, who taught his meaning of the phrase "wide-side-notch" with three courses of shingles that approached and went past the bottom corners of window frames. First, a wider shingle is nailed on - half under the sill and half outside of it. In the next course, a shingle is nailed alongside the frame, while the final waterproofing shingle is notched in an L-shape with part of it running under the windowsill and its length running up the side of the frame.

Historic building restorer Sandy Kendall, a carpenter on Nantucket for the last 36 years, said shingles need room to breath and move.

"Nail 'em high and leave some air space," he said. "What I see is guys with hand planes making perfect joints but they [shingles] get moldy. Nail them high

and they can curl up and dry off and leave a space - I