DIYers…. subbase / rubble question

I’m currently taking out an old patio slab which we want to turn back into lawn.  Turns out its a good foot thick so its taking a bit more effort than expected…

Worked out I will have around 6 ton of broken up concrete to dispose of, and a corresponding big hole needing lots of soil – rough estimate is disposal and soil will be quite alot – in the region of £1k.

So, we would also like to extend the old drive (was planned for sometime in the future, not now).  I’m thinking I could dig out the area for the drive, use the soil to backfill the old patio, and then the rubble from the patio for the drive subbase, then bang some MOT over the top to level.  We haven’t decided on a surface yet, likely to be either tarmac or gravel – I’m not planning on taking out the adjoining old concrete drive as I know that is up to 2 feet thick in places as we had foundations cut through some of it.

I have no idea why they wanted to use so much concrete in the 50s!

Is this a dumb idea?

I have no idea why they wanted to use so much concrete in the 50s!

Perhaps they just had ‘a lot’ of it? Are you anywhere near any decommissioned WW2 airfields? (Sorry, doesn’t really answer your fundamental questions)

Sounds like an excellent idea! It’s how I would do it, broken up patio and foundations will make a good drive base. Break it up as small as you can be arsed, lay it down and then type one over the top tamped/whackered level to fill the gaps. It will be something you perhaps weren’t intending doing yet but will save you money. Unfortunately the patio sub base sounds like my approach to longevity!

Sounds like a plan but what are you moving over from the patio, chunks of concrete or broken up rubble?  I would have thought your new drive sub-base would require comparatively fine stuff in order to be compacted.

Real mixture of sizes, biggest take 2 hands to lift, but most are about fist size.  like I said its not coming out without a fight.

And that foot thick is just the slab, there is then rubble / bricks and stuff under it which I think I’m going to leave, it doesn’t look solid so I reckon a foot of soil over the top will be fine for grass

I have started grading the rubble as I stack it (as i’m running out of space I’m having to go up…)  I think the bigger pieces I would still skip and use the fist sized and below bits, then cover with mot and compact

I also have a ton of mot already left over from the new patio base.

I’ve seen you can hire concrete crushers, not seen how much yet or if its possible locally or whether that is a false economy

re.  ww2 yes, alot of airfields locally in the new forest.

Don’t forget to account for the Mrs’ / victims bodies in any patio/foundation calculations.

I have no idea why they wanted to use so much concrete in the 50s!

I’d browse local news archives for unsolved murders :-)

It was quite voguish in the 50s for organised crime gangs to have a sideline concrete and civil engineering.

There is a bit of an odd smell as I’m taking the stuff out, like fish, I’m presuming that is the old soggy clay soil meeting the air for the first time in 70 years.  It’s gone when it dries out a bit.

So far nothing of interest, bodies etc…  other than a broken clay pipe and some sort of glass bottle lid / stopper.  Glass half full I was hoping for buried treasure, though maybe a body is more likely….

Its a good plan but bear/bare in mind that the volume of the dug out material will increase as it comes out so youll end up with left over material. Im going through a similar process digging out concrete floors to insulate.

We are hiring in a mini crusher, about 250 for a day and apparently will do 30 ton in a day. Will then reuse the crushed material – its way cheeper than skips, plus the volume will decrease. Currently it sounds like your sizes – usable as is, plus lots of heavy big lumps

Yep, that’s the opposite of what we did.

The soil dug out from the back garden where the summerhouse was going went into a raised bed out the front. And all the old crazy paving from out the front is buried under the summer house slab and patio.

Saved us a fortune in waste fees.

Probably best done this time of year as it took some effort to bed the rubble in properly so the base wasn’t full of air pockets.

You can use the rubble in with the MOT.  As long as you have enough MOT to cover it then you don’t need to add 50mm on top of that.

Sensible if you can make it work. Just breaking it up you won’t get nearly enough fines for a sub base though. You will need that crusher. I paid about £300 for a weekend crusher hire which was more than enough time and a lot cheaper, easier and more eco than skips etc. Worked perfectly. You can even adjust the grade that comes out. Some of it went in as mot, some went into the new concrete as ballast, even crushed some old tiles as garden chippings. It’s quite a fun machine to use.