Home DIY

Just straight smashing with a sledge hammer.

Whereabouts are you?

It won't kill you but it'll be really fucking hard.

Where is it?

Basically if you've got a solid slab firmly connected to the ground it's really hard. You hit the top of the concrete with your heavy (but relatively smooth) hammer and all the engery goes through the concrete and is absorbed into the ground below and dispursed through the slab.

What you need is an 'in'.

So if you can dig out part of it to create a void then the energy can't flow to the ground in the same way. If you create fault lines, etc. then it fractures along those and breaks. Etc

Does that make sense?

Having a look and a think. Possibly drilling or digging bits in the right place will have it smashed to peices with ease.

YouTube delivers
https://www.youtube.com/watch?v=w9DbICsil_o

You don't need to watch all of it. But see how when he starts hitting along that central crack it breaks it with one swing. But yet when he's just pounding it he needs 4 or more.

Easy for me to say, but I bet if he'd started by working his way along just the crack, then given the other two a pry bar or something to dig under a bit to create a void it the rest would have smashed up faster and probably into bigger single pieces.

The promise lands of Woking.

Back garden, I can dig under it at the corner I checked. I may just save the faffing and hire a breaker.

thank you, as ever. feels a bit scary making it much worse before fixing it but seemed to have gone well.

I did this last year with an old carp pond. Used a pointy chisel thing and lump hammer to make some initial holes and then expanded from there with sledgehammer. Very satisfying but very tiring.

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Pry bar and sledge will do it especially if you can undermine it but a breaker will chew it up in no time. With a sledge beware of flying chips of concrete hitting things like cars etc

pointy chisel thing

Careful with all these techinal terms, we're not all experts!

something like this would probs be a help:
https://www.screwfix.com/p/magnusson-guarded-concrete-bolster-3-4-x-16-/3822v

i pulled up an old concrete kitchen floor this way, didn't seem too bad..? but perhaps that's hindsight talking...

How solid was the kitchen floor? How much depth did you pull up? How long did it take and what did you learn? I had discounted being able to smash out the concrete ground floor in my 1950s house. It is freezing. I would like to add insulation. I have spent a long time looking for advice and there doesn’t seem to be much that is useful, things like “insulate under the concrete” only work if you don’t already have concrete…

There are two types of thin insulation that could work for me without smashing the concrete but both are expensive and have other draw backs - aerogel and vacuum panels.

If I could smash out enough to gain even 50mm then I could probably get 70mm of insulation in and a screed without losing too much head room.

If you have the head height one of these is a good idea https://www.tudorenvironmental.co.uk/tudor-chisel-and-point-steel-crowbar-6-039 just lift 600mm of the gound and let gravity do it’s thing. Once you get the hang of it you can do a load of damage without too much effort.

I think what you'd need to know is whether there is anything structural to the house about the slab, and how any services integrate into that.

Eg our 1950s house has the gas pipe running through the concrete slab, and now has some rad pipes running through another bit.

Thank you. Yes, interesting. The slab doesn’t have pipes in it, there is no gas, and the water comes in from outside above it, but I would probably have to get a structural engineer out to tell me if it is holding the house up I suppose.

here’s some progress photos - tbh can’t remember that much of the process, during-after-before judging by the upload order. Also dug out the hardcore/crush subfloor, as previously there was zero insulation.

feel like with many of these things, if it’s one-off (ish) DIY, any pains during the process are quickly forgotten - i’d certainly not say ‘i’m not doing THAT again’ for what it’s worth.

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The other consideration is impact on living arrangements - ie how long can you live without a floor, or can it be done in stages.

Thanks all, going to buy a massive hammer and a pointy thing.

I've done this to an external path before I built my extension. I would save my money and hire a breaker. You will do it in a fraction of the time

Thanks, looks ok. I read some retrofit eco website that said it is often not possible just because old concrete is too hard. I guess next steps are structural engineer and test hole.

Presenting without comment.

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Not sure that would help with the insulation problem

Quite a way to spend a penny

Smashing concrete update. Pointy thing is pretty useless but it's nice to finally own one. The slab is easy to break up if I have dug under it a bit. Digging under is easy as the ground is soft. I had a go at not digging under and it was hard work.

Let down by the basic bitchness of the rest of the bathroom. Needed more black marble and sparkles. And a soft close loo.