Glulam Tall Walls Tackle Oversize Windows

By Nate Traylor

When architect Bayliss Ward designed a home to feature a l4-ft.wide centerpiece window that reaches the height of the lS-ft. vaulted ceiling, he knew the home would have mother nature to contend with.

The Bozeman, Mt., home meets code in an environment with extreme snow and wind loads-thanks in part to glulam. "Glulam is typically three times as strong and a third smaller than [dimensional timber] ," said Ward.

Engineered to bear the elements, the latest in glued timber technology is called upon when walls rise higher than l0 ft. and feature those large panoramic windows so common in homes with the views to justify them.

Typically called window walls, these large, expansive windows provide sweeping views and invite plenty of natural light. However, they are a building challenge. When framed with dimensional lumber, window walls can crack under horizontal pressure from extreme wind loads.

"This rarely has to do with the quality of the window," explained Jim Blair of Rosboro, the largest producer of glulam in the U.S. "Even windows with a lifetime warranty can crack if not properly framed."

Tall walls, those between l0 and 30 ft. high, are increasingly common in new home construction. According to the National Association of Home Builders, the market share for firststory tall walls was 5.98Vo in 2001. That figure jumped to l97o in 2006. The market share for second-story tall walf s was .98Va in 2001 and 9Vo in 2006.

"We definitely see an opportunity here," said Kerlin Drake, Anthony Forest Products. "Tall wall [constructionl is giving glulam a larger part in the specification process."

Capitalizing on the growing tall wall demand, savvy glulam producers are are rolling out products to meet