Foundation for small building

I'm building a schoolbus shelter at the end of my driveway and for months I've been breaking my head over the foundation. It will be a small building, just 7' x 5' and about 8' tall.

The building will be made out of rough hemlock (4x4 and 2x4) with spruce log siding. I will also install two original schoolbus seats inside, so all together the structure will be super heavy. But I have no idea if it can get tipped over by the wind. It can be pretty windy around here, but I see so many building in this area that are just on cinder blocks and nothing happens to them.

I'm either going for concrete or just cinder blocks. If turns out it's too risky I can consider adding hurricane anchors afterwards. I will most likely also transplant quite some 8-9' pines that could function as a wind breaker.

If I'm doing concrete, the cheapest way for me would be to just order a cement truck and pour a foundation. I've been thinking about 8' or 12" x 4' concrete forming tubes but in the end it's a ton of work (very rocky soil) and even more expensive than a full slab.

Any advice or recommendations is appreciated!

Several of my neighbors have structures for that purpose and they're on skids. I'd probably build it like that, drag it into place and then watch it on a windy day to see if it needs anything more in the way of tie-downs or wind-breaks.

If it were me, I'd go with a slab.  For the cost, durability, and simply ease of building, a slab will probably be your best bet.  It isn't hard to anchor the building to it if you like.  If it were my building I would anchor it "just in case".

So many questions first!;
- where are you building
- how far does concrete need to come
- what is your soil type
- can you start with a pole structure
- can you drill holes for poles or dig them?

From the picture, I presume the seats will be along the back wall. As a bus shelter, I can think of no reason why the front wall needs to be 8' tall. I would suggest making the front just 7' or tall enough to fit the door, and sloping down to the back wall. That could be as short as 5'-6" and not risk anyone hitting their head since they will be sitting at the back. This would considerably reduce the wind exposure, and a small unheated space will be cozier in the winter and easier to warm with body heat.

I built a small fuel shed for Hubby with a shed roof with the tall part facing the prevailing winter winds and with enough slope to make it easy to remove our wet, heavy snow. I ended up having to add anchor ropes to the front even though it wasn't particularly enclosed - just tarps.
So when I made a wood shed using essentially the same design, I used less slope on the roof. It still vibrated enough that although it never tipped, it just wasn't secure enough.
When the fuel shed had to move and eventually I rebuilt it, I secured it down to the foundation and that's been much more satisfactory.

In all three cases, there were reasons the sheds had to face the windier direction. However, winds have been increasing in many areas, and there's another permie whose garden shed tipped right over, so to me it's not worth the risk of not fastening it down some how.

I hear you about the rocky soil - I see people digging holes all the time on the web or permies and making it sound so easy - NOT! The last hole I dug, Hubby had to haul out the rock drill and break it into 5 pieces to get it out of the hole and even then he needed help lifting one of the pieces!

I like Glenn's suggestion of lowering the roof to decrease the wind load and keep it warmer.

I just noticed the 'rocky soil'.
If the rocks are big enough you may be able to get a Ramset bolt in enough to bolt brackets and go from there.

Glenn Herbert wrote:From the picture, I presume the seats will be along the back wall. As a bus shelter, I can think of no reason why the front wall needs to be 8' tall. I would suggest making the front just 7' or tall enough to fit the door, and sloping down to the back wall. That could be as short as 5'-6" and not risk anyone hitting their head since they will be sitting at the back. This would considerably reduce the wind exposure, and a small unheated space will be cozier in the winter and easier to warm with body heat.

You seem unaware that these are his children...

It's been a while but the bus shelter is (almost) finished. I decided to go with a full slab, it was the most durable and smartest option. Only some window trim, painting and landscaping to do:

Daniel, your school bus shelter turned out really nice.

Looks very neat and official The round window is fun.

I do have some concern about the slab sticking out from under the walls all around. Every rainstorm will put water under the wall baseplate on one side or another, and I suspect it won't be too long before you get some rot at the bottom of the walls.

Nice results.

For others discussing this one other reason to look at skids instead is in Wyoming if it is under 200 square feet and on skids then it isn't counted in the property tax.  Does this apply in some form in other states?  The skids can be concrete so the base could be just as heavy.

In Illinois, the devil is in the details.  My understanding is Property tax can vary by what county you are in.  But there are other variables as well.  Allegedly, a farm building can only be taxed at a maximum of 1/3 of what is adds to annual farm income.   Of course, if one’s farm has no income, then the question gets raised if the property is a farm at all.  In my county, I have not heard of a building on skids being taxed.