Super dry fill, Impending rain and extra compaction

   / Super dry fill, Impending rain and extra compaction
  • Thread Starter
#11  
I will second the recommendation for a plate compactor. It works a lot better than driving back and forth over it. It's probably too late for you but when you are going to be pouring concrete, a base of rock (road base or crushed concrete) will be a lot better than dirt.
Well I left the dirt low about 3 inches (probably more after it settles) we will fill the rest of that in with crusher run in preparation for the concrete. I didn't want to fill the entire area with crusher run, that stuff ain't cheap anymore. I am going to start cruising FB Marketplace for a plate compactor. I see them for ~$500 or less a bunch.
 
   / Super dry fill, Impending rain and extra compaction #12  
Ill throw my 2 cents in on this one. ( I tend to over think things as well )

Assuming your ground water and surface drainge around this are is good then....

My concern would be the low point or the area of most fill having enough compaction and support over time. If its one corner consider digging down to clay and pouring that corner deep?

Is the current grade of the fill at where you want to put your concrete on top of you current fill or are you going to be cutting it back down to begin the process of preparing for a slab?

I assume you putting a couple inches of 3/4 clean under the slab for drainage?

Are you building the shed on top of the slab or can you build it like a pole building and have posts then put the slab down? This could be an option.


Talk dad into a wood floor?



I think if your cutting your grade back down you might be ok. Cut it down... wet and compact that.... add in your stone for slab drainage.... compact that... pour the slab and build.





In hindsite.... it would have been best to have taken off any topsoil then built back up using stone like the crusher run or clean 3/4 - 1 inch using a tamper to compact about 2 inch each time.

However.... keep in mind it is for a shed but yes still do not want major settling over time cracking the concret and twisting the structure.

Of course you can always build and see how it goes! Maybe have to come back and dig under to add support for that corner.

Good luck...!
 
   / Super dry fill, Impending rain and extra compaction #13  
Like the others have said. Water is a good thing. If the deep end was mostly filled in one lift it needs lots of water to help compact. On my big pad I watered it as much as I could and when we got rain I loaded up the dump truck and drove back and forth over the whole thing. I overlapped tire tracks then turned 90 degrees and did it again. Drive something REALLY heavy on it when it's really wet, you will find any non-compacted spots. I understand the plate compactor to do really well to settle the top couple inches and help the fines fill in. But if there is a void from underneath there's nothing better than something really heavy on a small footprint.
 
   / Super dry fill, Impending rain and extra compaction #14  
It sounds like you know what is needed to compact the soil. Best case scenario you would have used water and compacted in 2 lifts when the soil was initially placed.
Trying to compact 14" at once is doable but harder so ...... Based on possible soil settling later I would make the slab ridgid with a rebar mat. You can do this with an 18"-24" grid of 3/8ths bars tied to a single perimeter bar. That way the shed foundation will remain one flat piece if it shifts later. GL
 
   / Super dry fill, Impending rain and extra compaction #15  
Rain will provide compaction, do not disc it after…before maybe but not after. The more rain the better
 
   / Super dry fill, Impending rain and extra compaction #16  
he guy who I got it from said it was good dirt. It was a REALLY dense compact cherty clay,
Clay - an earthy material that is plastic when moist.
I would never call clay "good dirt" to go under concrete.
About 1985 I manually over-built a 15x20 shed. Hand dug about 6" into dense clay. Some of it involved using a pick and 5' pinch bar to break up the clay. When it rained and the water finally soaked into the cracks in the clay it was slick mud.
Then poured a truckload or 2 of #57 over it, built forms, put in some rebar, added 3"+ of concrete. I've stored motorcycles, parked my tractor in it, have not had a crack yet.
You might want to put some landscape fabric over the clay and under the concrete.
 
   / Super dry fill, Impending rain and extra compaction
  • Thread Starter
#17  
Clay - an earthy material that is plastic when moist.
I would never call clay "good dirt" to go under concrete.
About 1985 I manually over-built a 15x20 shed. Hand dug about 6" into dense clay. Some of it involved using a pick and 5' pinch bar to break up the clay. When it rained and the water finally soaked into the cracks in the clay it was slick mud.
Then poured a truckload or 2 of #57 over it, built forms, put in some rebar, added 3"+ of concrete. I've stored motorcycles, parked my tractor in it, have not had a crack yet.
You might want to put some landscape fabric over the clay and under the concrete.
Yeah, I will put some landscape fabric under the crusher run over the concrete.

I am no soil expert but I would say there are a lot of different types of "clay" soils. Clay is not actually a type of soil it is a grain size. But we associate a certain look or texture of soil "clay". To really tell exactly what you are working with one must crush the soil and run it through sieves to determine the different grain sizes. It is hard tyo tell excatly what I am dealling with in this soil. It was dug from 6 feet deep at the bottom of a bigger ridge. And again it was really dry. Once that moisture hits it we will see. I am pretty confident it will pack in quite nice. A guy that does this for a living called it nice dirt, I am inclined to believe him.
 
   / Super dry fill, Impending rain and extra compaction #18  
To compact soil, and add moisture, it needs to be dug up and mixed, and then put back in place in layers. The thickness of the layer depends on how you are going to compact it. On commercial jobs, like roads and parking lots that I was on, it was built up in just a few inches and then gone over with a sheepsfoot vibratory roller. This goes on all day, day after day, until it's built up to where it needs to be. Even with a water truck adding water, and loader mixing the dirt, a dozer spreading it, and a huge sheepsfoot vibratory roller compacting it, it's still very hard to pass the test when working on a small area.

As a home owner, you will never get full compaction. You can get something that's workable, but most of the time, it's never even close. If you can drive over the soil with your tractor front tires, and a full load of dirt in your loader, and the soil doesn't settle, or sink it from the weight of your tractors, you need to keep working it. Once you get it hard enough to support the weight of your front tires with a load of dirt in the bucket, that's about as close as you can hope for.

How far away from the edge of the pad where the shed is going to be built is the retaining wall? The retaining wall is where you will have your biggest issues. Compacting next to the wall is even harder then compacting a small area. The farther away you have the retaining wall from the building, the most compaction you will get in the soil under the building.

Railroad ties do not last very long when they touch soil. Railroads put them on top of a bed of rock that allows water to drain so they don't sit in water after it rains. The wood used for railroads ties is considered junk wood that isn't good enough to make real money. The tar, or coating, or whatever is used on them will remain in place as the wood rots out on the inside. The bugs will eat it out from the dirt side and the railroad ties will look fine for years, but then one day, you will see something odd about them and realize that there isn't anything left inside of them. Cement retaining wall blocks when installed properly will last a lifetime, railroad ties will last a decade.

Deep footings around the walls, or setting treated posts in the ground will compensate for soil that isn't compacted fully.

In all likelihood, just pouring a concrete slab on the soil after you've driven over it a bunch of times with your tractor will give you something that should be fine. A shed is not a house, and expectations are not the same. Get it as good as you can and realize that it might need some maintenance in the future.

Rebar in the slab, resting on chairs, is the standard for a proper concrete slab. Anybody that pretends to pull up the rebar while pouring should not be hired. Anybody that suggest using wire instead of rebar, or fiber instead of rebar, should not be hired. Those are fine when added to rebar, but they will never replace rebar. The biggest mistake in pouring concrete is adding too much water so it flows easily. The concrete should pile up on itself when poured, and fight you when spreading. If it flows like soup, it's too wet and it will crack!!!! Cracks happen because of too much water. Rebar holds it together and adds strength, but too much water will still crack the concrete.

A slump test is easy to look up online. Knowing what slump is will stop them from adding water to the mix. Every crew will try to add water, it makes a huge difference in how much easier it is to spread.
 
   / Super dry fill, Impending rain and extra compaction #19  
Well I left the dirt low about 3 inches (probably more after it settles) we will fill the rest of that in with crusher run in preparation for the concrete. I didn't want to fill the entire area with crusher run, that stuff ain't cheap anymore. I am going to start cruising FB Marketplace for a plate compactor. I see them for ~$500 or less a bunch.

This is one area that renting kind of makes sense, since most people only need a compactor once in a blue moon. I just used one for a shed base. About $60 for a 4 hour rental. I think this was the second time in my life I rented one and I'm really old.
 
   / Super dry fill, Impending rain and extra compaction
  • Thread Starter
#20  
To compact soil, and add moisture, it needs to be dug up and mixed, and then put back in place in layers. The thickness of the layer depends on how you are going to compact it. On commercial jobs, like roads and parking lots that I was on, it was built up in just a few inches and then gone over with a sheepsfoot vibratory roller. This goes on all day, day after day, until it's built up to where it needs to be. Even with a water truck adding water, and loader mixing the dirt, a dozer spreading it, and a huge sheepsfoot vibratory roller compacting it, it's still very hard to pass the test when working on a small area.

As a home owner, you will never get full compaction. You can get something that's workable, but most of the time, it's never even close. If you can drive over the soil with your tractor front tires, and a full load of dirt in your loader, and the soil doesn't settle, or sink it from the weight of your tractors, you need to keep working it. Once you get it hard enough to support the weight of your front tires with a load of dirt in the bucket, that's about as close as you can hope for.

How far away from the edge of the pad where the shed is going to be built is the retaining wall? The retaining wall is where you will have your biggest issues. Compacting next to the wall is even harder then compacting a small area. The farther away you have the retaining wall from the building, the most compaction you will get in the soil under the building.

Railroad ties do not last very long when they touch soil. Railroads put them on top of a bed of rock that allows water to drain so they don't sit in water after it rains. The wood used for railroads ties is considered junk wood that isn't good enough to make real money. The tar, or coating, or whatever is used on them will remain in place as the wood rots out on the inside. The bugs will eat it out from the dirt side and the railroad ties will look fine for years, but then one day, you will see something odd about them and realize that there isn't anything left inside of them. Cement retaining wall blocks when installed properly will last a lifetime, railroad ties will last a decade.

Deep footings around the walls, or setting treated posts in the ground will compensate for soil that isn't compacted fully.

In all likelihood, just pouring a concrete slab on the soil after you've driven over it a bunch of times with your tractor will give you something that should be fine. A shed is not a house, and expectations are not the same. Get it as good as you can and realize that it might need some maintenance in the future.

Rebar in the slab, resting on chairs, is the standard for a proper concrete slab. Anybody that pretends to pull up the rebar while pouring should not be hired. Anybody that suggest using wire instead of rebar, or fiber instead of rebar, should not be hired. Those are fine when added to rebar, but they will never replace rebar. The biggest mistake in pouring concrete is adding too much water so it flows easily. The concrete should pile up on itself when poured, and fight you when spreading. If it flows like soup, it's too wet and it will crack!!!! Cracks happen because of too much water. Rebar holds it together and adds strength, but too much water will still crack the concrete.

A slump test is easy to look up online. Knowing what slump is will stop them from adding water to the mix. Every crew will try to add water, it makes a huge difference in how much easier it is to spread.
YOU DA MAN EDDIE!!! Thanks fore that excellent, honest and thorough post. Yeah, I honestly think with some added moisture and a bit of work with the tractor and a plate compactor I think it will work just fine. I might try to talk dad out of a slab. The last shed he had installed 40 years ago at his last house settled so now he is gun shy and doesn't want it to happen again.
 
 
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