Sheet-drain system is the correct call for Louisiana wood plant

With geosynthetic sheet-drain technology, a more-efficient and cost-effective system was proposed and eventually built.

A new engineered-wood manufacturing facility is up and running this year, thanks in part to a comprehensive geosynthetic sheet-drain system.

Martco Limited Partnership, the manufacturing arm of the Roy O. Martin Lumber Co., completed a new oriented-strand board (OSB) plant near Oakdale, La., this year that is the largest of its kind in North America. The $210 million state-of-the-art facility, 30 miles southwest of Alexandria, is the second Martin Co. OSB plant in Louisiana.

At full production capacity, this plant will utilize about 1.7 million tons/yr. of small-diameter pine pulpwood and produce 850 million ft.²/yr. of ³⁄₈-in.-basis OSB board. OSB is often used as sheathing in roofs, walls, and subfloors. About 170 hourly and salaried employees are now working at the new Martin Co. plant.

The construction plans for this facility included a “press pit” requiring a 30-ft.-high, 23,000 ft.² underground wall. The original design called for an intricate drainage system using pipe and stone. But with geosynthetic sheet-drain technology, a more efficient and cost-effective system was proposed and eventually built.

Specified in this project was a two-part, prefabricated soil sheet drain consisting of a formed polystyrene core covered with a nonwoven, needle-punched polypropylene filter fabric on one side of the core. The fabric is bonded to each dimple to prevent soil intrusion into the water channel, and allows the water to pass into the drain core while restricting the movement of soil particles that might clog the core. The core provides compressive strength and allows water to flow to designated exits (Photo 1).

Sheet drain is designed primarily for vertical, one-sided, sub-surface drainage applications requiring an increased compressive strength and a high flow capacity. For this installation, the core side was placed against the wall surface of the foundation, providing full-coverage protection to waterproofing materials (Photo 2).

Sheet drain products typically are used where large surface areas require drainage. Vertical applications include foundations, basement walls, and retaining walls. Horizontal applications include plaza decks and green roofs.

The entire surface area can be covered to provide maximum drainage capacities. Sheet drains usually are made in 4-ft.(1.2m)-wide sheets in rolls 50-100 ft.(16-33m) long. The core can be ¼- to ½-in.(6-12mm) thick. Most sheet drains also serve as protection for waterproofing material (Photo 3)—as seen here at this new OSB facility—thereby eliminating the cost of a separate protection board.

Trang Schwartz of American Wick Drain Corp. and Ron Bygness, editor of Geosynthetics magazine, contributed to this article.