Using hardwood posts

[Bricklayer]

I've been saving 4x4 hardwood lengths from work now for 3 years. They are mostly ash and oak. Probley about 9' lengths most of them. I was planning on making a couple harvest tables out of them but the tables would weigh a ton. I figured since I have enough, I could built my 14x20 sugar house with them. Post and beam style
Is using hardwood ok for this. I know it will be a lot harder to work with then pine or hemlock but my theory is why not. It's free. I also picked up some 12' 3x8 pine also left over at work that I will be using for the rafters.
It's a concrete slab on grade build also so none of the posts will be in the ground.

[maple flats]

Oak will be hard to work with since when fully dry it is very hard, BUT it would last a very long time. Ash, easier to work and will last good if not in direct contact with moisture. Either will make a great post and beam sugarhouse.
You may want to isolate the bottom of the posts from the slab to minimize moisture transfer.

[Bricklayer]

I will be putting 2 courses (16") of 6" concrete block on the slab all the way around. Then sill gasket and use the 4x4 posts for a sill plate. Notching the sill plate 2" every 4' to attach the posts to.
A friend of mines father was a carpenter and believed everything could be made out of oak. He made a trailer hitch out of oak for a trailer at his farm and it is still in use today. Probley 40 years old.

[maple flats]

Oak does last longer than you would think. Back in the early 80's my brother, father and I were cutting firewood in a section that had lots of Swamp White Oak. As we made the logging road we ran against a log across the trail, it looked all punky. My dad cut it, scraped off about a half inch of punky mush and the rest was hard and solid. It was maybe 6-8" diameter before cleaning off the punky part. Dad sawed it and used it to heat his greenhouse. It was very solid inside.

[Ghs57]

I timber frame using mostly eastern white pine (EWP) or hemlock (the local evergreens), but, when needed, hardwood posts may be called for. Some guys say they are easier to work than EWP or other evergreens. Of course, they are green when used in framing. My stuff's all small, so I haven't used too much hardwood. EWP dulls chisels in no time flat though. I just rough cut some poplar posts, so I am interested to see how they are to work. They also dulled the chainsaw quickly. All our ash here is dead and has tuned to mush.

Good luck with the building. It should be very nice that size, and with a concrete floor. I'm very envious.

[johnallin]

Oak does last longer than you would think.

White Oak is very rot resistant and is used often in wood boat construction for that reason. Red oak is a completely different animal and will rot very quickly.

[maple flats]

John is likely correct, the logs I mentioned above were "swamp white oak" not red oak. That woods had no red oak.

[GeneralStark]

If you keep red oak dry it will last a long time. No reason not to use hardwood for timbers...