They Don’t make ‘Em Like They Used To – Update #4 (February 20, 2013)
Over the past year or so we have been posting on the changes in the design values for Southern Yellow Pine. You might recall that 2011 test results for the strength values of 2×4 lumber showed that the strength values for Southern Pine were about 33% lower than listed on the strength value tables. Tests were performed on other sizes of Southern Pine lumber in 2012 and the official results are here.
New design values for all sizes and grades of visually graded Southern Pine were released on February 11, 2013 by the Southern Pine Inspection Bureau (SPIB). Click HERE to review the new design values in Supplement No. 13.
A quick review of the results for 2×6’s through 2×12’s shows a reduction of about 10% to 25% depending upon the size and grade of the lumber. This is much better than the 33% reduction for 2×4’s. The new design values take effect on June 1, 2013. But since the design strength of the lumber available today is probably more in line with the new values it may be prudent to use the new design values immediately for critical members.
The SPIB states, “Southern Pine’s strength and stiffness remain comparable to other softwood species used in residential and commercial construction.”
In this process we have seen that the procedure set up for the review and correction of wood design strength values has worked very well.
We still plan to specify Southern Pine where it is of benefit to the end user.
I suspect that this post will be the close for this topic.