Small pole barn advice

[LD1]

The cost savings of going with fewer and smaller posts to get back to reality will probably save enough money to pay for concrete

 

[mopardude318]

let me fix this post

 

[Gary Fowler]

With your house location, you have to haul in fill to the low side, no excavation on the side near the house or you will have a water run off problem.
I would haul in crushed rock and compact it in with either a roller or vibratory plate. Make sure your fill extends at least 6 feet from the side of your building on the low side so that you can put a gradual slope on the fill for drainage without washing.
I would go with a slab for sure and then build on top of the slab. You can set L shaped anchor bolts in the concrete when pouring so you don't have to drill and set concrete anchors. As others have said, get your trusses established first and your engineering done so you know where you have to have the uprights set (and the sizes) so you can correctly set the anchors.

When I built my 30x30 shop on a concrete slab, I had my builder put a layer of 8"x16" CMU blocks (wish I had gone with 2 layers for the additional height) around the perimeter and then built on top of that using 2x4 standard house construction. I had this done for a several reasons, 1) it allows me to power wash my floors without getting standing water on my walls 2) it also raises the siding up off the ground so rain splashing doesn't get on the outside siding3) it gives me additional ceiling height.
The blocks are tied into the slab with rebar and concrete fill and walls are tied to the blocks with embedded anchor bolts.

 

[drizler]

Yup if youre ever gonna go slab do that NOW and save your self the headaches later. I like the idea of putting a cinderblock base around the perimeter because in my case it gets walls out of the snow and imagining in your case to keep the bugs off of it like termites. 2 blocks high might get your walls up high enough that you can do the walls close enough to your 10' that you can do the walls in 8' lumber (should be cheaper). 4x6 is plenty fir uprights.
One thought on trusses, why 6/12 in sun country? Tin roofs get pretty slippery so why not go shallow pitch and make it easier on yourself unless you are going to try to squeeze some storage out of the middle of those trusses. You won't get much anyways in practical terms. One thing for sure you won't need all that pitch to shed snow. Drop it down to at least 4/12 if possible and you'll appreciate it greatly while you're up there working.

 

[Gary Fowler]

My roof is a 4/12 x30 foot span and I have a center width of about 12x30 feet that is more than 8 feet high at the center and more than 6 feet at each edge. That adds lots of storage area for bulky lightweight items. Admittedly, I don't have a lot of stuff up in the attic and I don't know what the PSF loading really is, but it is there. When designing your trusses, you could specify what amount of loading that you wanted to shoot for and see what the trusses would look like for various load factors.

 

[mopardude318]

Well here's an update. I decided to go with a slab. For some unknown reason I thought it would be a good idea to dig down slightly and level the area, which turned out to be a minor mistake. It costed me double the amount of base rock needed, about 70 yards, and two days time spent on a jumping jack and plate vibrator. I will say I built it back up and compacted the heck out of it.

It's formed up now with an 8" wide stem wall on 3 sides. The slab will be 6" thick with 1/2" rebar on 18" centers. It'll take about 40 yards of concrete.

 

[mopardude318]

 

[mopardude318]

 

[EddieWalker]

I'm a little late to this thread and what is done is done, but why did you dig out your soil and replace it with gravel?

 

[mopardude318]

I had a thought in my mind that if I dug it out and inset the slab into the ground below grade on the high side and have the stem walls hold the surrounding area, I wouldn't have such a large approach on the low side. But that was the flaw in my thinking and that's not how to do it. I would be fighting water entrance for life.

So in doing what I did, I screwed myself and had to buy a whole bunch extra base rock to build it back up. Its now compacted and solid as it was before. On the next one I'll listen and not jump the gun. Live and learn.