Getting into my head too far. How to support my storage shed?

[rooster59]

I would look into using packed crushed rock and treated 6x6s or 4x4s. If there’s a bit of slope then definitely cut in some drainage.

 

[Sanderguy777]

I would look into using packed crushed rock and treated 6x6s or 4x4s. If there’s a bit of slope then definitely cut in some drainage.

Yeah, that's the plan. There is a slope, and I'll need to work out how much I adjust it, but there will be good drainage and all that

 

[MushCreek]

Also- weather wind reports are measured at 33' above the ground. During a tropical storm with winds reported at 60-80 MPH, my home weather system, which is only 8' above the ground measured a peak of only 22 MPH. We lost a number of massive oaks, but at ground level nothing got moved around. Unless your shed is sitting out in an open field with nothing around it, the wind probably isn't a factor. The one exception is tornadoes, but as we said, most sheds (or anything else) is not going to be tornado proof. Our house is made with reinforced concrete walls, but we still go down to the basement during tornado warnings.

 

[mike93lx]

I would never put wood in the ground for a structure. Sono tubes and brackets for me

I did a 8x8 shed a couple years ago with one tube at each corner. The floor was framed to allow for that and it's really solid. For an 8x12, 6 tubes and a couple 4x6's or two pairs of 2x8 are probably what I would do

 

[firebirdparts]

Would this work, or is this a terrible plan?

It's a great plan to hold up serious weight, but I think the 12" concrete in the bottom seems like a lot. As I mentioned above, I find it pretty easy to dig post holes, and if you want cone-shaped holes, you can do that easily using a hand post hole digger. I did exactly what you are talking about here when I rebuilt my deck. To keep your posts off the bottom of the hole, you can support them with something at grade. Stick a 2x4 on the side of it temporarily.

 

[firebirdparts]

P.S. You mentioned rammed earth/no concrete. If you do that right, it's amazing how much hard work it is. It's way harder than digging the holes. On the farm, we used to build cow fences that way when I was a tough teenager. Brutal.

 

[Fav Onefour]

I would never put wood in the ground for a structure. Sono tubes and brackets for me

I did a 8x8 shed a couple years ago with one tube at each corner. The floor was framed to allow for that and it's really solid. For an 8x12, 6 tubes and a couple 4x6's or two pairs of 2x8 are probably what I would do

I don't like the idea of putting the posts in concrete. There is a reason for standoffs and those are used above grade. It truly amazes me how many repairs I've done because of rotted wood from contact with concrete. The part that amazes me is the fact people are still using the practice. Today's treated wood isn't like the old days of posts dripping with creosote and tar. Some of the big box treated lumber is junk just waiting for an excuse to fail.

Keep it simple. Pour a decent flat pad and build an anchored shed on top.

 

[CraigStu]

This was a discussion w/ my garage contractor about redoing the fence we had to move which I said I'd cover. But I think it has some application here. His experience was dig the hole for the post, put 3-4' of gravel in the bottom, stick the post in and fill around it w/ tamped soil. He said that the problem w/ concrete around the post is there is no way you can keep rain from seeping down around the post into the concrete. Especially if there is concrete at the bottom of the post, that post spends it's life soaking in rain and that is why posts always rot and break off at or just below the concrete surface. So my take away from that conversation is this; if you want posts in the ground do as above. If you want to use concrete, build piers and use brackets on top to attach the wood.

 

[Sanderguy777]

Also- weather wind reports are measured at 33' above the ground. During a tropical storm with winds reported at 60-80 MPH, my home weather system, which is only 8' above the ground measured a peak of only 22 MPH. We lost a number of massive oaks, but at ground level nothing got moved around. Unless your shed is sitting out in an open field with nothing around it, the wind probably isn't a factor. The one exception is tornadoes, but as we said, most sheds (or anything else) is not going to be tornado proof. Our house is made with reinforced concrete walls, but we still go down to the basement during tornado warnings.

Did some searching and it looks like uplift becomes an issue even with an EF0 tornado if you are too close. Any direct hits overwhelm anything I could build, obviously. But a 6 post system with some bolts through the post inside the concrete and 24" deep concrete piers poured around them has enough that the roof is leaving well before the posts do.

With them, I could handle 100+MPH winds just fine. without them I only need 66mph to flip it. You're right about the trees blocking things, but we had linear winds that took down tons of trees. Imagine what a swirling wind would do.

I would never put wood in the ground for a structure. Sono tubes and brackets for me

I did a 8x8 shed a couple years ago with one tube at each corner. The floor was framed to allow for that and it's really solid. For an 8x12, 6 tubes and a couple 4x6's or two pairs of 2x8 are probably what I would do

That's so expensive, though. Posts in concrete gets me significantly more lateral strength (no bracket to bend) and saves about $250 on brackets. Wrapping it with impermeable plastic and adding through bolts makes it last longer and let's me use a smaller amount of concrete. It won't last quite as long, but would last 40+ years probably.

 

[Sanderguy777]

This was a discussion w/ my garage contractor about redoing the fence we had to move which I said I'd cover. But I think it has some application here. His experience was dig the hole for the post, put 3-4' of gravel in the bottom, stick the post in and fill around it w/ tamped soil. He said that the problem w/ concrete around the post is there is no way you can keep rain from seeping down around the post into the concrete. Especially if there is concrete at the bottom of the post, that post spends it's life soaking in rain and that is why posts always rot and break off at or just below the concrete surface. So my take away from that conversation is this; if you want posts in the ground do as above. If you want to use concrete, build piers and use brackets on top to attach the wood.

The issue he is talking about is that there is air and heat and critters at the surface and to about 6" below. Those exist everywhere, especially in dirt.

Concrete can cause the issue if it gets water into the seam, but that isn't an issue since it would be covered by the siding. Also, I plan to cover the posts with impermeable plastic so there is little to no contact with the concrete at all, and any water will have to get into the shed, and then up 6" of concrete or more.

The idea he had WOULD work great in an area with good drainage (I wanted to do that myself), but the issue is that the soil here is clay. My yard has an 18" deep pond in the back. It is so bad draining, that it was filled by one storm, and still had 12" of water in it 2 days later when the next storm hit!

My parents' yard has a slope,so it is better than mine, but it's still got the same clay. (Also, there is apparently a shelf of rock between 2 and 20 feet down right underneath us LOL)

 

[CraigStu]

.....
Concrete can cause the issue if it gets water into the seam, but that isn't an issue since it would be covered by the siding. Also, I plan to cover the posts with impermeable plastic so there is little to no contact with the concrete at all, and any water will have to get into the shed, and then up 6" of concrete or more.

Ah, I see what you are saying.

 

[Sanderguy777]

Ah, I see what you are saying.

I could do that with the post protector things, but as someone said, packed earth is a lot more work than concrete.

 

[mike93lx]

Did some searching and it looks like uplift becomes an issue even with an EF0 tornado if you are too close. Any direct hits overwhelm anything I could build, obviously. But a 6 post system with some bolts through the post inside the concrete and 24" deep concrete piers poured around them has enough that the roof is leaving well before the posts do.

With them, I could handle 100+MPH winds just fine. without them I only need 66mph to flip it. You're right about the trees blocking things, but we had linear winds that took down tons of trees. Imagine what a swirling wind would do.





That's so expensive, though. Posts in concrete gets me significantly more lateral strength (no bracket to bend) and saves about $250 on brackets. Wrapping it with impermeable plastic and adding through bolts makes it last longer and let's me use a smaller amount of concrete. It won't last quite as long, but would last 40+ years probably.

I hear you. Not telling you what you need/should do, just my take

 

[Sanderguy777]

I hear you. Not telling you what you need/should do, just my take

Yeah. I'm just worried about the tornadoes. you're almost certainly right, but if it flies away I didn't save anything.

 

[mike93lx]

Yeah. I'm just worried about the tornadoes. you're almost certainly right, but if it flies away I didn't save anything.

If a tornado takes a shed on sonotubes, it was done anyway

 

[Sanderguy777]

If a tornado takes a shed on sonotubes, it was done anyway

Oh, for sure.

I was talking about just setting it on gravel or something and the savings not being worth it.
If it's in concrete then it's with not going anywhere, or the house will be gone and no one will be worried about the shed