Building wood with freshly felled hemlock and cedar.

[Breckinridge Elkins]

But that really doesn't go to the OP's question.

The boil it down:
Pressure treat would be a better choice for those posts than hemlock or cedar. If you want to use what you have on hand, use the cedar but place a pad of 30# roofing felt between the wood and the concrete.
The green hemlock will be fine for framing the shed.
Any hemlock exposed to the weather needs to be dry, primed, painted.
A shed built like this will outlive it's owner, even in WA (I built homes in western OR as well).

 

[Mad Professor]

Then I'd recommend slamming some metal fence posts in the ground and draping a tarp (blue of course) over the posts. It might last a winter if one drains the rainwater off it--in a normal western WA winter that would be every day.

I've read the complete Lewis and Clark journals, and their stay at Ft Clatsop. I understand the rain.

 

[Mad Professor]

Hemlock makes nice trim . View attachment 1149820My barn built in the early 1800s used black locust posts and beams that made ground contact . I need to replace some of the sills but close to 200 year life span is good enough for me

Locust is great wood for ground contact, fence posts will last 40 years untreated. Take care of that old barn!

The real go to wood for sills back then was chestnut. The sills in my timber framed home are original chestnut and date from early 1800s. I'm ~100 miles northeast of your location.

I got to learn about timber framing, old barns/houses restorations, from Richard Babcock, a master timber framer.



He also taught me scribe rule layout, all done using a divider/compass, chalk lines, and a plumb bob. No need for a: square, rulers/tapes, etc.....and as accurate as any modern layout method. Also hewing timbers from logs.

If your barn is early enough it may be scribe rule. If so You'll see the layout lines on the joinery, and someplace on the frame will be a series of scribed circles, usually on a plate or tie beam. The circles are the compass/divider settings that were used to do the layout, and serve as a reference if repairs were ever needed.

Here's a woodrack I built using ash I milled, you can see the layout line in pencil and chalk. I used a drafting compass w/pencil, and chalk line for layout. And joinery done with old hand tools.

I mentioned scribe rule as OP was going to use round posts. You can scribe joinery accurately to a round post or irregular out of square timber, and frame will be 100% square.

 

[SS396driver]

The barn is pre civil war

 

[Mad Professor]

The barn is pre civil war View attachment 1149859View attachment 1149860View attachment 1149861

Nice!

I'd like to see some more picture of the joinery and how the frame is laid out, but don't want to hijack this thread.

 

[SS396driver]

Nice!

I'd like to see some more picture of the joinery and how the frame is laid out, but don't want to hijack this thread.

I’ll start a thread need some more pictures