Fixing bodge job in paving for shed

I've got a new shed on order, arriving in 4 weeks and being assembled by the supplier. I finally pulled down the old shed today, which is sat on a pretty basic patio of large slabs pushed pretty much right up to each other, but sometimes with a small 1-2mm gap.

Removing the old shed revealed that the centre of the patio has been bodged together even more than the surrounding slabs. See pic.


What have they done here? There seems to be a lot of sand? What is the easiest and quickest way to fix it?

It won't be visible as the new shed is bigger than the old one and will totally cover this middle bit of the patio, so I don't care about how it looks.

Should I just try and find some slabs to fit? Or is there some easy way to get some kind of level concrete in this middle bit?

I've got 2 kids under 3 so I don't have much free time to do this - so easiest and quickest solution would be preferable!

Also I want to totally kill the possibility of anything growing up through the patio, so what should I do to this centre section and the gaps between the surrounding slabs to achieve this?

Many thanks.

EDIT: Sorry, I didn't mention that the centre bit of the patio is not flat at all, it's got some big undulations that go higher and lower than the surrounding slabs by up to 10mm! And from what I understand - sheds need to have a decent flat base in order to go up properly.

JoeA said:

It won't be visible as the new shed is bigger than the old one and will totally cover this middle bit of the patio

Click to expand...

Just leave it as it is then.

Also I want to totally kill the possibility of anything growing up through the patio.

Click to expand...

Generally weeds don't "grow up through", they grow down into due to seeds blowing in.
So first, eliminate sources of seeds e.g. nearby out-of-control patches of dandelions.
Then there are special sands that you can brush in to gaps that discourage germination.
But ultimately, just accept that sometimes you will need to poke out a weed. (Train your kids to do it.)

Sorry, I didn't mention that the centre bit of the patio is not flat at all, it's got some big undulations that go higher and lower than the surrounding slabs by up to 10mm! And from what I understand - sheds need to have a decent flat base in order to go up properly.

If its in the way of the new shed bearers then remove it and replace it with some lean mix concrete If its not in the way then leave it as it looks relatively solid. Nothing will grow if there is no light. Looking at the levels i doubt there are any level flat spots so the shed will undoubtedly need packing up here and there etc so this may take you clear of the high spots.

Was the old one sat directly on the flags or on packers of some sort?

I don't think it's very solid, large chucks of what seemed to be mostly sand were coming away when I prodded it.

Old shed was directly on patio.

So... I've dug up the offending patch. It looked a bit like concrete that hadn't been smoothed down at all, but it broke apart very easily, and had a very sandy consistency.

This is what I'm left with.

Can I literally level the surrounding slabs and then pour concrete into the hole, using the current slabs as the boundary against which the concrete sits?

Yep no problem, sounds like the best solution. Scrape out the loose stuff and pour in the concrete. Use a length of wood to level it with a sawing action and that'll do. If you want you could trowel it lightly to smooth it but not really needed.

Considering I have no access to a mechanical mixer, would it be easier to just buy some slabs to fit in the hole? Or would mixing up the amount of concrete needed for this hole by hand, be achievable? I'm just a bit nervous as I've never used concrete before.

Either is fine, It shouldnt be a huge amount to mix by hand. You could mix it on a sheet of wood no problem.

or look out for the thick plastic spot mixing tray/boards. They have a rim to reduce spillage and are easy to clean. I also use mine for mixing up compost, and holding the spoil when I dig planting or fence holes.

About £18 in DIY sheds.

I think you will need 10 ballast and 2 or 3 cement.

You won't need to go to the gym after you have mixed it

Many thanks for all the advice, in the end I decided to fill most of the gap with flags, and then I concreted the little bit left over in the middle.

Now there is a shed sat on it, all my lovely work is hidden anyway!