Questions first, details second:
Is 8-10% and 12-15% MC SYP dry enough to use for a workbench in a non-insulated garage shop in Austin, Texas?
Given that the MC ranges across a board, which figure should I use? Max? Average? What about small wetter spots?
My cheap moisture meter states "Measurement accuracy: ±4% for both hardwood and softwood". Does that mean a reading of 10% could actually be 6% or 14%? Does that make it almost useless for determining if wood is dry enough for woodworking?
I started building a Roubo-inspired workbench during my vacation which has 1 week remaining (back to work on 1/14). I was really hoping to have it done by then. The plan is to build a 4.25"x28"x6' top by gluing up 8/4 Southern Yellow Pine. The base will be made from doubled up 8/4 SYP as well.
I chose SYP because it is pretty darn cheap here in Austin, Texas and is recommended by Christopher Schwartz in his book on building workbenches. I was sourcing from lumberyards when I found my local Big Box store sells construction grade "kiln dried" #2 prime SYP for dirt cheap. I picked through the stacks and found some decently straight and clear 2x10x12' flatsawn boards that I could rip in half.
I wasn't considering moisture content because it was advertised as "kiln dried". When I got home I could feel that one of the boards was noticeably damp to the touch (not sure how I didn't notice at the store). I bought myself this cheap $45 pinless moisture meter to check it out. I moved the meter over the face from one end to the other. That board ranged from 35-40%... Luckily, that board was from a different bunk/stack than the rest. Of the others, about 1/2 read between 8-10% across the board with spots at 11% and the other half 12-15% with spots at 16%.
This is my first large furniture project so I started reading up on acceptable wood moisture content. I learned a lot but was also inundated with often conflicting information lacking context. Some put a dead stop on figures like 9% or 12%. My case may be atypical since I am building a beefy workbench and not fine furniture. As such, I don't mind cosmetic flaws like small cracks that might result from the wood settling as long as they are not detrimental to the integrity. Also, the bench will not be indoors and instead in my non-insulated garage shop and exposed to the changing humidity. This site states "In most of the U.S., when wood is outdoors but protected from the rain, the wood will attain an EMC of 12% when the RH is 65%" "in more humid locations ... wood outdoors can attain 16% EMC." So maybe the wood is actually about were it should be for outdoors in Austin? Idk
It seems quite a few people have built workbenches using construction grade SYP from a Big Box store without reporting any issues. Am I overthinking and over-worrying?
Let me know what you guys think and I appreciate any input.