Posted by Sherman in Idaho [24.32.202.166] on Monday, July 15, 2013 at 20:09:42 :
In Reply to: Yes... posted by Doc Dave [75.139.109.12] on Monday, July 15, 2013 at 16:40:40 :
That stuff started to show up (marked "SPF") on the west coast during the last building boom. The "Fir" in that grade is true fir, also called "white fir", not doug fir, which is graded higher. The standard west-coast construction lumber is "hem-fir", which is hemlock and/or true fir, the claim being that a lumber grader can't tell the difference at a glance. In reality, it's mostly hemlock (obvious if there are black knots or black wanes in very white wood) The trouble is it rots very fast, which is particularly bad on the wet side of the mountains where they sell so much of it. I stupidly used it on the barge rafters of my garage in about 1985, and had to replace them to sell the house 20 years later. Meanwhile the barge rafters on the house itself, which were doug fir, had been there since 1915 and still showed no sign of rot.
On the coast, you have to pay a premium for doug fir. We're lucky in North Idaho that the standard construction lumber is "D Fir-L", which means "doug fir or larch" Both are strong and rot-resistant, especially when they come from this area where they grow slowly. Some of that SPF I saw that came up from the south during the boom had growth rings 1/2" wide.
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