The state of North Carolina advised inspectors today against automatically disqualifying European lumber on Tar Heel construction sites or automatically requiring an engineered design. But builders will need to provide additional information for the use of that foreign wood to be acceptable.
"DOI will be releasing web interpretations (https://www.ncosfm.gov/interpretations) later this week noting how to safely use such lumber," wrote Carl Martin, a deputy commissioner of the North Carolina Insurance Department. "Note that the documents will be fluid while additional information is received or developed.
"Today we are aware of only one European species, Norway Spruce from Romania/Ukraine, that has insufficient ability to hold fasteners (specific gravity <0.42) and should not be used for carrying loads without proper engineering because the required nailing pattern will be affected," Martin added. "This and other information will appear in the web interpretations."
The state's update was prompted in part by the alarm bells sounded after its June 15 alert declaring that North Carolina's Building Code Council "has determined European lumber ... does not meet N.C. building code requirements and, in some cases, could cause catastrophic failures in wall, floor and roof framing."
The Pacific Lumber Inspection Bureau, American Wood Council, and American Lumber Standards Committee replied with memos that basically argued most European lumber is safe to use provided engineers consult span tables for those species. "Adequate resources exist for use by plans examiners, builders, and designers to accommodate the use of European lumber with these standards," AWC's statement said.
That argument is similar to one that Pak Yip, a state Insurance Department construction code consultant, made in a June 17 phone call with Webb Analytics. He said said the possibility of failures could be avoided if builders simply take care to follow the American Wood Council's design values and similar documents that specify the expected strength of European species. Then be prepared to show a building inspector you followed those rules.
Yip said North Carolina's building code focuses on just four wood types for construction: Douglas fir, SPF (spruce-pine-fir), Hem-Fir, and Southern yellow pine. Before the COVID pandemic, these were the state's go-to construction materials. But as supplies for these products dwindled and prices shot up, imports of lumber from Europe began to rise.
Typically, European lumber imports are most popular on projects nearest the East Coast ports where they arrive. But Yip estimated European lumber is being used in "tens of thousands" of projects across "just about all" of North Carolina's 100 counties. The dollar value of imports of forest products from European Union nations between January and April rose 64.5% from the same period last year, the U.S. Department of Agriculture reports.
The problem, he said, is that builders are used to planning homes based on the qualities inherent in the four common North American wood types. "If people are using the [span] tables [for those products], even if they pick the lowest one and use it for European wood, that span could be 30% too long," Yip said. "I'm not saying 100% of the European species are weaker, but some of them are."
The state Insurance Department alert had similar language, declaring: "... European lumber can only be used as an alternate material that must be reviewed by the code enforcement official before it is used. This does not mean European wood products are prohibited, it simply requires additional supporting documentation to assure the wood characteristics are properly reflected in the overall project design."
One problem is that this statement came in the second-to-last paragraph of the statement, while the headline read: "N.C. Building Code Council warns of the use of European lumber in North Carolina." Fears have arisen that the wording of that headline and the early reference to potential catastrophic failures might lead people to avoid selling and using any European wood.
The bottom line, Yip and others told Webb Analytics, is this: You need to look beyond the number on the grade stamp to notice what type of lumber it is. Then use it based on its distinct properties.