Barn options

I'm going to be putting up a 41x40 bolt together Quonset shed. Looking at going two Lego blocks high for the foundation. They will be sitting on packed inch minus Rock about a foot deep into the ground. I am in Southwest Illinois. This will be for cattle and sheep. Think I should go deeper with the packed rock? I figured that would be down to the clay and a little deeper.

You may not be that far from me. I'm close
to Rend Lake

That sounds like a good plan to me.

I dont know what LEGO block is. But if it is 8inch
wide concrete form. I dont know how that wont turn
on you in time. Around here we have to pour 2ft by
8 inch thick footing and set on that No packed
gravel just dirt and clay to pour onto.

IMHO pouring a concrete footing 2 foot high x 8 inch wide is a lot easier than laying cinder/concrete blocks (if that is what you mean by LEGO Blocks). I have no idea how deep you need to go in your
location. I usually try to get below the frost line and always get below the organic material.

How are you planning on holding it dowN? As I am understanding it you get a big wind and it would be in the next county. I think you need fastenerd to a 3 foot deep concrete foundation. Neighbor had a pole barn pulled up out of the ground by wind, did not break a pole but pulled them all up out of the ground and this is heavy clay. Here those blocks would be pulled up with the building if you had it fastened to blocks in any way.

Poured concrete wall with some good anchors in the concrete is the way to go.

If the blocks are what I think they are, they are about 2 ft square x 6 ft lg. If that's what you are talking about, you are probably fine as long as you can live with a
little bit of frost heave. You may want to consider banking up a couple of feet on the outside of the blocks to counteract the outward force of the walls and the buildup
of bedding on the inside

I think that it will depend on the soil and slope. If water can drain off you should be good but if the ground below your rock is clay you could end up with enough moisture to cause bad heaving especially if you get a rain followed by a hard freeze. Your roof will have the potential of putting a lot of water under your blocks.

How would you sujest it be fastened to the blocks?

A Quonset building is relying on the anchorage at the ground to hold it down and keep it from flattening out. As others have
said lego blocks? whatever they are, probably will not give you the lift protection or side support needed for your building.
Drainage will be a huge issue as a lot of water will cascade down both sides to saturate the soils alongside your support
blocks. Your area probably has a frost line near 48 inches. A cast in place concrete wall down below frost line will give you,
1) a good point of anchorage for the side wall. 2) great horizontal support for the bottom of the sides. 3) Best opportunity to
direct drainage away from the building with backfill at the cast in place wall. I do know of a Quonset that is setting on
crushed stone, the closed in end walls hold it together and keep the wind from lifting. So it can be done. Do whatever you want
or can afford. Many times I have regretted doing something on the cheap. You will be so happy to have a building for your stock
and machinery. I know I was. gobble

My 30' Quonset is on poured in plce footings and cross tied with steel I would think a 40' would push more and not being in the tied would be
a disaster.

First thing that comes to mind is, how are you going to bolt it
down to the blocks? If they are not selling you the Z track for
the base ask them why,and then be ready to look for a different
building. My seller didn't mention the Z plate till after I had
agreed to buy,then he wanted another $1,500.00. I told him
no(made me mad)It would have been a lot cheaper than pouring the
U shape concrete foundation.
You will need a way to hold the building up while is goes up. At
the very least you need a flat packed floor down the center.
Mine is 40X60X16,mine is 1/2 inch off end to end. Wind just
blows over it, not a flat surface on it. Mine is a shop,if I had
to do it again it would be a pole barn. Hard to run
water,electric,and air lines without putting holes in the siding.

Bkpigs is asking about drainage not about blocks to use and securing to the blocks. There is a known and proven and accepted method of securing the frame to the blocks. Pretty much the same as used for huge fabric barns. Go see your local building inspector. He can look it up in the national building code.

The YT Members map lists Bkpigs at Okawville.

On of the biggest issues with a Quonset building is the amount of side force they place on a walls
I don't know what the lego blocks you've mentioned are but the instructions that comes with a quonset building state clearly the the walls or pads need to be tied together to prevent them from pushing out or rolling

We built a 40x44 in 2010, the photo looks bad as we had 3 rings up when a storm front rolled in and layed it back, we disassembled it and used rubber mallets to reshape the pieces and were able to reuse all of them
I posted the photo to show the walls and cross ties
The walls are 3 ft tall setting 12 inches below ground level, the outside of the wall is tapered so the wall is 18 inches at the bottom and 12 inches wide at the top. The cross ties are 6x6 concert with 1/2 inch rebar tied into the walls
A local shop bent me a 3/16 galvanized trough for the buildings panels to set in, they are anchored to the concert wall with 1/2"x4" tapcon anchor bolts, once the building was finished we filled the pockets in the trough with grout to add weigh and shed water



Here is the nearly finished barn 7 days later, we back filled around the walls so that they are 18 inches below grade
What is not shown is the 3 inch stone we added to the inside to raise the inside floor 6 inches above the outside dirt
It may have been a little overkill but I live on top of a hill were we get some pretty strong winds and after 10 1/2 years it hasn't moved
I'm 80 miles east of Evansville, Indiana so our weather is pretty close to the same

Before doing anything, consult your county building inspector.
Frost line in TH is 24 inches, so setting on crushed rock may
not pass building inspector.

Just something to think about. In the 50's my dad had a Morton 3
sided pole barn for cows. In the winter you wanted to avoid the
pole barn around 9-10 am when the sun melted the frost off the
underside of the roof, it was raining cow pee..

A "lego block" is a concrete block about 2' high, 2' wide and 6' long, weighing I think around 3500lbs.

They are made from surplus concrete that comes back from jobs at the ready-mix plant, and are relatively cheap for what you get.

Some are called "lego" because they have pins and holes like the lego toy to interlock. Others have a simple key and keyway to allow stacking.

They're dry-stacked in a typical "running bond" brick laying pattern.

You would fasten the building down to the blocks the same way you'd fasten it to a poured slab or wall. On a 40' building you've got 14 of these blocks or almost 25 tons, holding the building down if you do nothing else. Fasten the first row to the second, and you have 50 tons holding the building down.

Lego blocks:

Google up "concrete lego blocks". I never hear of them before but I think he's going to have a substantial foundation there that the bidg. can be tied to with little worry about wind.

Sorry for the delay, busy at work and home. Yes, I live in Okawville, IL. The blocks will be 2x2x6 weighing 4,000 pounds each. If I do 2 rows it will be 39 of the 6 footers and 3 of the 3 footers. Roughly 80 tons. The building will be bolted to the top row and the top bolted to the bottom.