How to break concrete?

sancho

I have a 4ft by 4ft piece of concrete in by back garden which I believe had a shed of some description on it. I want to remove it to extend the lawn

I started trying to remove it late last year........

It's about 10 inches deep (probably more substantial than the footings on my house!) I have attacked it with a sledge hammer, drilled holes to make it weaker, then hammered again, used an angle grinder to make 'sections', then hammered again. No joy.

I got sick of it and gave up, but now I want to get it sorted for this year, I have put the job on mybuilder.com and the quotes are around £300 :eek: which I won't pay, I rang a hire place this morning and they say the only breaker they have is more for paths (3-4 inches deep)

Is there anything else I can try (semtex would be useful i think....)

Thanks in advance

optimus_primera

When you tried to sledgehammer it, where did you start?
Start by breaking off one corner, then carry along one edge and do it that way.
http://http://www.hss.com/g/2151/Vibration-Damped-Breaker-110v.html

http://http://www.hss.com/g/2111/Heavy-Duty-Breaker-Avt-110v.html

one of those will do it.
Just ask for extra points and chisels.

macman

Must have been the best built shed ever with a 10" base! Try another hire shop for a Kango or similar that will tackle the heavier jobs.

Ebe_Scrooge

A breaker is going to be your best bet. If it really is that deep then it's still going to be hard work, but it's do-able.

Two other options. If you have the necessary access, you could look into hiring a mini-JCB for half a day. This is likely to be pretty expensive though.

The best way - and this involves a bit of luck, but worked for a mate of mine - if the gas board or water board or anyone happens to be digging up the road nearby, if you ask very nicely and slip them a few quid each, they may be prepared to come round and break it up for you. The big breakers they use are much more powerful than the ones you can hire yourself. Might be worth a try :-)

sancho

Funnily enough they are re surfacing my road from tomorrow, not sure they'll have a breaker though, the bloke who spoke to us implied they were using big machines.

No access for a digger which is a shame.

It really is that deep! I think the people must have had shares in concrete, it is really dense stuff too, hardly any gravel in it. I'm going to have another bash in a bit, will take a photo

27col

You might find that the slab is only thick around the edges. In the middle it might well be only 100mm thick.This is a well known way of providing a good base for a shed.

DVardysShadow

The way to break concrete manually is to start with a sledgehammer until you put cracks in, and then use a heavy crowbar with a point, working on a crack by hitting it with the point. Sooner or later you will get the bar in far enough to lever the concrete apart

bobhawke

Hit it directly in the middle with a sledgehammer until it breaks. It will be the slowest and hardest option but you will get a hell of a workout (cardio, core strength, forearms, grip).

Canucklehead

O.P.: as said, hire a breaker. It will cost a bit of dosh but will save you time and aches. The OH uses one for drains work etc.

Canucklehead

DirectDebacle

Drill a line of holes edge to edge and not quite all the way through. Hammer in tight fitting dowls and then soak with water. Never tried it myself but apparently a similar method was used by the Egyptians to split granite for building pyramids.:D

I do know that expansion of wood is a powerful force and once started (almost) nothing will stop it.

If it works it will be very MSE.

sancho

Success!!

I've obviously got stronger, or more angry.....

I started on the corner as suggested and managed to chip away bits until I'd broken about a third of it, then while using a spade to dig a bit near it I noticed I could get underneath it and lever the whole thing up, couldn't lift it though, not even a mm. so I jimmied the spade under it and gave it a wallop where it promptly broke into 4 (equally heavy) pieces. Was reasonably easy to then make those a little smaller, well just 'lift-able'

Was pretty much 8 inches deep throughout the whole thing, underneath there is a small amount of gravel and sand, and guess what's under that? ...........

That's right, more concrete!! Is only an inch or two and seems to be coming up with a spade. I'm seriously worried there is plutonium or a dead body somewhere under there though, you really could have put a house on it.