I want to transform my South London back yard into a rural idyll. Currently my back yard is almost completely covered in concrete, with an extra thick bit where a ludicruously oversized shed sits (that's going too). I guess I want to remove this, but how do I go about it? How thick is it likely to be? Do I need to hire a pneumatic drill or similar?
When I remove it, will I likely just have soil underneath?
Another consideration is that manhole covers and drains are built into the concrete.
1/ hire skip and be prepared to hire another because there's probably more concrete there than you think, especially if you leave it in big chunks ;-)
2/ go at it with a selection of sledge hammers (my fave) or an electric drill/breaker/SDS+/- ... until it's all in the skip. this willprobably take more than the time set aside for the purpose. this is also normal.
that's what's called an easter egg, you never know
try electric 1st, one of them cheapo £35 SDS jobbies from screwfix et al ought to do it but, as I said, I prefer to use a big FO sledgehammer and reduce the concrete crust to wheelbarrow sized chunks.
hopefully, watch out for pipes, cables, ex tennants, bombs etc.
indeed. best get rid of the concrete before deciding what to do about them :)
I rented an electric breaker. I can't remember how much or what type, but it was 110 volts so I needed a transformer, so could indicate an industrial type. It cut through like a knife through butter and some of that concrete was 9 inches thick. I did try a sledge and chisel first but it bounced off. Cheers Graham
However thick the people who poured it wanted it to be. When I had a 900mm deep retractable post fitted into an area of concrete a few years ago, the builder didn't break through the bottom of the concrete when digging the hole. However, it had once been a runway.
You don't need to, but it will be a lot easier if you hire an electric or pneumatic concrete breaker. A chap I know simply invited a lot of friends around, laid in lots of alcohol and got everyone to help with the job. He had two concrete breakers and several wheelbarrows.
You won't know until you take it up. Properly laid concrete should have a wel-compacted sub-base below it, although you might just find a layer of rubble. You are unlikely to find useable topsoil, so you will need to buy that in. Someone else I know simply broke a few holes through the concrete, built dwarf walls and put the topsoil over the concrete in raised beds.
Lift them to find out how deep the drains are. If they are shallow, breaking the concrete above them might damage them. Take care breaking the concrete around the manholes, in any case.
Thinking out loud.... what about hiring a petrol still saw and score the concrete around the manhole covers and then score the surface in a grid pattern all over.
What will this do????
It will allow the concrete to be seperated from the covers/drain easily and then while you have use of the saw all day you might as well score the whole surface and make it a bit easier to break up the concrete into manageable pieces.
Unless the concrete was built to withstand WWIII it's probably easiest to smash it using a big (as big as you can comfortably lift and swing) sledgehammer. It's surprising (and very satisfying) how easy it is to break garden-grade concrete if you hit it right (and suprising how feeble power tools that are quite macho at knocking holes in walls are in this application). The trick (as with swinging an axe) is to start the swing with hands at opposite ends of the handle (right hand at the head end if you're right-handed) and in mid-swing transfer the right hand about half-way along the shaft to accelerate the swing. Try not to slide your hand along the shaft or you'll quickly get blisters. Cotton (e.g. gardening) gloves are probably a help, maybe the sort with rubber blobs on the outside to give grip.
Been there and done that, biggest cost is the skips, large at £100 + vat, I hired a bosch 10kg breaker and transformer which, if your concrete is thick i.e. 4" + makes it relatively easy, wear eye protection and gloves
Build upwards instead. Use stone to create flower beds and fill with good qaulity earth. Use sawn in half barrels for shrubs or small trees. Remember concrete has one advantage - no weeds !
This will be the third reference to safety kit! In addition to goggles & gloves, buy a pair of toe capped boots. Doing this sort of work is a REALLY good way to trash your toes. They don't cost much, and if you aren't doing this often will last forever, your toes will thank you.
As no one seems to have mentioned it so far, "air" is your friend here! As in, concrete will break much more easily if you can get a space under it. So hit it a bit to get a crack, then use a very long lever to lift the edge. If you are working with someone, get them to clomp it while you have it levered up, if working on your own you need to leaver a bit up, kick some half bricks/rubble under it, and then go clomp it yourself.
Having played this game before I found a sledge, long bar, and pick did half the concrete I needed lifting very quickly. The other half required a hydraulic breaker and a 1.5 tonne mini digger!
I had a concrete garden path that was about 3 inches thick. A sledgehammer or pick just bounced off it unless you really got savage with it, but then there seemed to be more prospect of damage occurring to me rather than the path.
I then hit upon the idea of trying to lever up a section of it, using a strong pole. Once you can prise the concrete away from the ground by just an inch or two, it only needs a tap with a club hammer to break it off into manageable bits. Seriously, it needed so little force to break it that a child could have done it.
The only trick is to put something under the raised section so that it stays off the ground when the lever is moved, otherwise you have to keep lifting it again.
60 feet of paving was demolished in a part of an afternoon. The only hard bit was barrowing it all away.
I could have done the whole job in the time it would have taken me to drive to the hire shop and return their kit afterwards.
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The op will not be able to lever up his yard in that way but he could try undermining it.
The reason why it breaks relatively easily when unsupported is that concrete is very strong in compression but weak in tension (unless it has been properly reinforced).
One of my friends has a kid so destructive that all you would need to do is invite him round to play in your yard and tell him to be careful because the concrete is expensive and delicate. It'd be dust and fragments in an hour....
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