Cheap Concrete Pads for Plastic 8x10 Garden Sheds

Old 10-21-18, 05:20 PM
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Cheap Concrete Pads for Plastic 8x10 Garden Sheds

My knowledge of concrete is just about enough to make me dangerous.
But, I can build the forms, mix it, and work it up to get reasonable slabs for the sheds to be placed on.

I live in an area where precipitation is in the 150"/yr range, so wooden platforms are out of the question.

I will be erecting a couple of HD special type plastic yard storage sheds soon.
I have been setting up the location by spreading 1-1/2"- red cinders to make a place to put them.
It has been a few months since I began spreading the cinders.
I am not finished yet.
Due to the time and rains since beginning to spread them, the location, so far, has become very firm and looks to be a good stable base for the slabs.
There is still enlarging and leveling to be done yet.

Each pad, if 4" thick, will use almost a cuyd each.
The cost of using a Quickcrete mix is going to be too high for my Scottish blood.
Doing a "standard mixture" will be too complex to gather up and still quite expensive.

The most abusive use for these sheds will be parking a riding mower and other yard machinery in one, and tool/materials storage in the other, very light duty use with a plastic floor over it.

I have loads of the 1-1/2"- red and black cinders sitting in the yard.
They are the same screenings, but overall the black is much finer.

The black is much softer than a regular aggregate, and the red is a bit softer still.
I think they can be used in a portland cement mixture in what would normally be classified as a C5 mix, fulfilling my needs nicely.

Old 10-21-18, 10:30 PM
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1-1/2"- red cinders
Unfamiliar with the term, what is a red or black cinder?
Old 10-22-18, 01:50 AM
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The cinders are broken up volcanic rock, hardened lava.
I purchase them by the truck load for things needed doing around the yard, filling in low areas, a gravel for the driveway and as a base for making soil.
They are rock not dirt.
The fines are sand.
The black is harder than the red.
They should make a somewhat light weight concrete compared to a denser aggregate as would normally be used.
They have been used in the past as aggregates for road asphalt around here.
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Old 10-22-18, 03:15 AM
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Do those volcanic rock cinders deteriorate over time? That would determine how suitable they are for the aggregate.
Old 10-22-18, 06:32 AM
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I would place cinders and compact with a rented tamping machine and forget the concrete. If this proves unsatisfactory, you can always add concrete pads down the road.
Old 10-22-18, 02:06 PM
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For all intent and purpose the cinders do not deteriorate.
They are porous which is why they're lighter in weight.
They do not dissolve in water like limestone, coral sand and similar.

I'm only going to do this one time.
I'm 75.
I can do this now.
Don't know about 5 years down the road, though.
Plus, I have other projects to get done, too many to go back and redo one that was supposed to be finished.
Old 10-23-18, 03:05 AM
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I did a quick search on ACI's (American Concrete Institute) website and it appears it's been researched (I suspected it might have been) using pumice for aggregate. ACI wants you to buy their study paper, but maybe you can find a free version online with a little searching.
Old 10-23-18, 04:09 AM
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@Bruce H
I think you've put me on the right track.
That link set me to looking at self leveling concrete.
A high percentage of fines giving a much easier to work mix.

Even if I screw up and make a relatively low strength mix, the use is not so abusive that I really need to worry about it very much.
I will look further into it.

I am beginning another project tomorrow, replacing the roof panels, and the screening on the screened area of our back lanai.
I should be finishing that in less than a month even if I drag my feet.
I will spend time looking further into the concrete while doing that.

The eruption has held me up for about 6 months in getting this started.
I'm antsy to get going.

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