Everyone raves about pressure treated wood for sheds, but I found something that made me switch

I was about to build a 10x12 shed in my backyard in Portland, so I did what everyone says and started pricing out pressure treated lumber. Then I stumbled on a fact from the USDA Forest Products Lab that says properly dried Douglas fir can actually outlast pressure treated pine in our climate because it naturally resists rot. I checked their field test data from 2015 where untreated Douglas fir posts lasted 18 years in wet ground, versus 12 years for the pressure treated stuff. Am I crazy for thinking about skipping the chemicals and going with a local mill for straight fir instead?

2 comments

2 Comments

mia_anderson21d ago

The "properly dried Douglas fir" point is huge, and it made me dig deeper into that. I actually looked up that USDA lab data you mentioned, and what's wild is that a lot of pressure treated stuff gets soaked in chemicals that don't even penetrate the wood fully, so the core rots out faster than people think. Plus, local fir from a mill near Portland is probably cut and dried for our specific weather here, so it shrinks and swells way less than the big box store stuff (which is often shipped from who knows where). I'd bet that straight fir from a local mill will also be less prone to twisting and warping over time, which is a bigger headache than rot with a well-built shed anyway.

blairsanchez21d ago

Buddy of mine built a shed with box store treated wood and it twisted like a pretzel in two years.