For over a year, Canadian sawmills have drilled a few holes in each board of lumber they produce, which ostensibly allows homebuilders to easily loop electrical wiring through them but which also allowed the Canadians to call them a "finished product," and thus exempt from U.S. tariffs on raw lumber. Siding with U.S. lumber interests, customs officials subsequently closed the loophole. The homebuilders lobby says the change could cost the average U.S. homebuyer $500.

†