Cement Slab in Wet Boggy Ground

Asporadic

Im about to build a small slab down beside the river. Its my land dont worry.

The problem is the land is always a bit on the boggy side and Im wondering what way this will work with the cement.

Ive a hole dug (its 4ft x 3ft and about 2 ft deep) and I have a wooden frame built with some 4 x 1.

Im gonna fill the hole right up with gravel, right up to the last 4 inches and then put the frame in. Get the frame level and then fill the rest up with cement.

Would I be right doing it that way or should I do it differently.

Thanks for any input

wayoutwest

Asporadic - What are you gonna be building on your slab?

Asporadic

wayoutwest wrote: »

Asporadic - What are you gonna be building on your slab?

Nothing :P
Its just a slab for putting a small picnic table on.

You wouldnt see it by eye, but the ground is at very slightest slant downwards. The table wouldnt sit right at all (and the boggy ground wasnt helping matters).

So I decided to dig the ground and put some gravel down. But of course, at least once a year the river floods into the garden and it would wash away the gravel. So Im just gonna put a cement slab down and save all the messing.



EDIT: The finished job should look something a bit like this:

Philip82

Hi, sounds like a nice job, one thing you could consider is throwing a few steel rods into the cement when pouring to help
reinforce the slab so that if the ground underneath does sag or sink that your concrete slab wont crack or break!!

wayoutwest

Asporadic - So you've dug down two feet...are you down to something that is naturally compacted [ie: rock/clay/gravel] and is'nt brown organic stuff?
Compaction of the hardcore is the key to preventing subsidence of the slab in the future. It's too small an area to be hiring a whacker - a sledgehammer and a bit of effort will do the trick. Put in one 'layer' of hardcore ,whackit down before adding the next layer - finish off with an inch of sand [also compacted] - this will stop the wet concrete from settling too much into the hardcore.
The shuttering boards should be secured in place with some pegs[ bits of 2"x1"]
Concrete = 1 cement / 5 aggregate [mix of gravel and sand].
You could round off the edges, using curved edging trowel if the slab is higher than level of lawn.

gutteruu

If you didn't dig deep enough to hit something fairly solid, you can drive a load of stakes into the ground under and around the slab. Then cut flush with the ground. They act like friction piles and should help stop the slab settling. I would also recommend using some steel.