I am about to cut several thousand board feet of 4/4 cypress, dry it, and then machine it in a ship lap pattern (avg 8 1/2" wide boards with 1/2" laps) to use as siding. The client wants me to hang it vertically as he is going for a barn look. It will be installed over 1/2" vented battens spaced 36" vertically.
Reading a quick synopsis of Cypress written for Sawmill & Woodlot by Dr. Wengert, it says to expect approx 1% size change across the rings (tangentially) for each 5% change in EMC. Reading from the tables in "EMC of Wood in Outdoor Locations in the U.S. and Around the World" (by W.T. Simpson, and published by the USFS FPL) it says that the EMC of my location near Charlotte NC varies from a low of 11.4% to a high of 13.8% throughout the year.
So if I dry the Cypress to 12% initially, I should still see less than 1% of seasonal movement (or less than .085") as the outdoor EMC range is less than 5% over the course of the year.
Am I doing this right? And further, I should be able to place two columns of fasteners in each board without fear of splitting because the amount of seasonal variation is so small, right?
Any corrections or amplifying info would be much appreciated.