Yet Another Cycling Forum

General Category => The Knowledge => OT Knowledge => Topic started by: mrcharly-YHT on May 11, 2014, 03:18:50 pm

Title: Getting through 12" of concrete
Post by: mrcharly-YHT on May 11, 2014, 03:18:50 pm
I need to make sure that the enormous pit, aka ex-pond, drains before I start to fill it in with rubble, sand etc. The space will then become useable.

Bought a 400mmx12mm drillbit to drill exploratory, hopefully draining holes.

I now know how thick it is. 12" concrete base. The centre has a sunken bit about 8" across and the concrete at the bottom of that is only 6" thick. Managed to drill about 10 holes in total yesterday - but it still didn't drain. Could be compacted rubble below the concrete, could be clay, could be anything. Ideally I'd remove a chunk a couple of feet square and make sure it can drain, but short of explosives I can't see any practical way of doing that. 12" is too thick for any cutting saw, too thick to break up with an SDS drill or even a jackhammer. Absolutely ludicrous.
Title: Re: Getting through 12" of concrete
Post by: Poly Hive on May 11, 2014, 03:26:12 pm
Interesting one.

All you can realistically do is to use your drill bit to make as many holes in the foot square you want as the drain. If you also use a bolster hammer and a chisel you will hopefully be able to remove a fair bit of material then drill down again. There are longer bits available and you might consider hiring a Kango hammer or similar.

Good luck

PH
Title: Re: Getting through 12" of concrete
Post by: Torslanda on May 11, 2014, 03:42:46 pm
If it's a pond there's no replenishment, yes?

What's wrong with a pump and a long hose? Get the water out and get it filled in PDQ . . .

Sorry if I haven't understood.
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 11, 2014, 03:47:19 pm
Because it will fill up with water from the rain.
Title: Re: Getting through 12" of concrete
Post by: Ham on May 11, 2014, 04:46:39 pm
A Kango will do the job. If you want to remove the concrete use a spade bit, if you just want to drill holes a chisel bit will go through.
Title: Re: Getting through 12" of concrete
Post by: tiermat on May 11, 2014, 04:50:30 pm
6" was about the thickness of our kitchen floor, and it was >70 years old.

Make a hole approx 6" across, then break it up from the edges. A small impact driver might not cope, but a two handed job shouldn't cost too muchmore to hire, and should be doable in a day.
Title: Re: Getting through 12" of concrete
Post by: Ham on May 11, 2014, 05:14:54 pm
No need for 2 hander (although obv better at it) Something like: https://www.us.hilti.com/drilling-%26-demolition/demolition-hammers-%26-breakers/r287 will get through just about any domestic situation.

(I have the 15 year old version of the same, I've not found anything it won't get through)
Title: Re: Getting through 12" of concrete
Post by: PaulF on May 11, 2014, 05:45:38 pm
Surely the standard answer to this sort of problem is "Dust off and nuke it from orbit. It's the only way to be sure."

:D
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 11, 2014, 05:51:36 pm
12" of concrete doesn't break that easily - I've dug out concrete floors and broken things up.

A kango will chip away, sure, but it won't smash this up.

Anyway, I've re-drained out the rainwater (getting fountained in sludge in the process) and drilled again through the same holes I did yesterday. There was 4" of water in yesterday so I couldn't probe about much.

There is clay under the pond. So no matter how big a hole I make, it isn't going to drain.

There is a 6" pipe leading to the lowest point in the pond. I reckon I can feed a pump down through this, rigged to a float switch. Really not the solution I wanted but looks like it is the only way.
Title: Re: Getting through 12" of concrete
Post by: Tim Hall on May 11, 2014, 08:38:46 pm
Hire a diamond core drill from HSS (other tool hire outlets are available)?

like this: http://www.hss.com/g/1121/Light-Duty-Diamond-Driller-Kit.html (http://www.hss.com/g/1121/Light-Duty-Diamond-Driller-Kit.html)
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 11, 2014, 08:41:06 pm
um - I'd need the heavy-duty version - that is £162 per day :(

As I said tho, still wouldn't drain because of the clay. It's going to have to be a pump
Title: Re: Getting through 12" of concrete
Post by: David Martin on May 11, 2014, 09:17:34 pm
Concrete will disintegrate on repeated vibration, such as from a jackhammer. When you have a hole, excavate underneath. Concrete is realtively strong in compression but not in extension - it should be easy to break into a hole.

Obviously the challenge is to get a hole from which you can excavate (possibly through pumping out the water, then washing away the clay into a slurry.)

..d
Title: Re: Getting through 12" of concrete
Post by: mike on May 12, 2014, 07:22:32 am
hire a breaker...  Dad asked me to get rid of a 10' x 10' x 2' concrete block when I was about 18, tried using a sledgehammer and it was stupidly hard work. Persuaded him to hire a pneumatic breaker and it was done in a day - and was quite good fun too (in an 18-yr-old, only for one day, kind of way)
Title: Re: Getting through 12" of concrete
Post by: asterix on May 12, 2014, 08:11:56 am
Dyn4mite. 

You need an expert quarryman, demolition expert or maybe a tree surgeon.

May we assume it is not reinforced with steel? :o   After all, they were clearly anxious to do a proper job of it..
Title: Re: Getting through 12" of concrete
Post by: andyoxon on May 12, 2014, 08:20:39 am
Short of a pneumatic type drill/kubota mini digger, I'd try and remove a plug of concrete by means of closely drilled holes, then excavate a hole into the sub-whatever (as has probably been said).  But 12" of concrete is one super thick pond lining... Our's is 1-2mm butyl sheet, with old carpet underlay.  ;-)
Title: Re: Getting through 12" of concrete
Post by: Jaded on May 12, 2014, 08:46:09 am
Could there be a carpet with bones in it underneath?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 08:59:30 am
Could there be a carpet with bones in it underneath?
It had crossed my mind!

There is absolutely no need for it to be so thick; 4" would have done the job, 6" would have been more than ample. 12" is ridiculous, particularly given that it also has a heavy fibreglass liner.
Title: Re: Getting through 12" of concrete
Post by: jogler on May 12, 2014, 09:18:33 am
Is it practical to consider infilling the ex-pond pit with clay?
Title: Re: Getting through 12" of concrete
Post by: Ham on May 12, 2014, 09:21:23 am
So your alternative is to report your suspicions to the Police with added local rumour that the previous incumbent's wife/grandfather etc disappeared some years ago.

Job done, you won't have to lift a finger ;)
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 09:40:36 am
Is it practical to consider infilling the ex-pond pit with clay?

Well you see it is over 7ft deep (about 1.5ft of which is above lawn level. - and my wife want to use it as a sitting/firepit area, slightly sunken. This weekend I discovered that rendering it in such a state takes priority over all else, even putting up a wardrobe for her clothes.

The whole thing is ludicrous. It is big enough for two hippos to have a bath in. It is visible from space. The garden really isn't large - the pond takes up over a 1/4 of the whole garden.
Title: Re: Getting through 12" of concrete
Post by: vorsprung on May 12, 2014, 09:45:45 am
Is it practical to consider infilling the ex-pond pit with clay?

Well you see it is over 7ft deep (about 1.5ft of which is above lawn level. - and my wife want to use it as a sitting/firepit area, slightly sunken. This weekend I discovered that rendering it in such a state takes priority over all else, even putting up a wardrobe for her clothes.

The whole thing is ludicrous. It is big enough for two hippos to have a bath in. It is visible from space. The garden really isn't large - the pond takes up over a 1/4 of the whole garden.

Ignore the drainage problem and cover with decking?
Title: Re: Getting through 12" of concrete
Post by: hatler on May 12, 2014, 09:47:22 am
So your alternative is to report your suspicions to the Police with added local rumour that the previous incumbent's wife/grandfather etc disappeared some years ago.

Job done, you won't have to lift a finger ;)
I worked in the world of underpinning for a while. The foreman of one of our gangs was arrested on suspicion of murder. The police believed they had quite a good case, except they needed the murder weapon, an axe I think it was.

The gang had just finished a large underpinning job and the police came to the conclusion that the axe was in the bottom of one of the bases. They asked him which one. He pointed them at the one, and the police hired his gang to dig it out. It wasn't there. "Oh, perhaps it was that one." It wasn't. I don't know how many they worked through, but it was a great way to have his gang trebly employed for a good period of time.
Title: Re: Getting through 12" of concrete
Post by: rafletcher on May 12, 2014, 10:00:37 am

There is clay under the pond. So no matter how big a hole I make, it isn't going to drain.


But on top of that will be topsoil - otherwise your garden would be a constant lake surely? So, rather than draining out the bottom, don't you need to drain through the sides at some level between surface and clay subsoil?

Of course, you'll discover the transition will be above the level at which the aforementioned SWMBO will want the sunken level to be.....
Title: Re: Getting through 12" of concrete
Post by: jogler on May 12, 2014, 10:02:06 am
Is it practical to consider infilling the ex-pond pit with clay?

Well you see it is over 7ft deep

'kin ell :o

that'll be a "no" then
Title: Re: Getting through 12" of concrete
Post by: Vince on May 12, 2014, 10:09:46 am
Fill it with rubble then cap off with a 12" concrete floor at the desired depth. Then make drainage holes through the side.You should be able to dig a soak away at the side of the pond liner avoiding the clay.
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 10:27:26 am
Not a bad idea, Vince.

I can make an exploratory hole at the side to see what happens - if a jet of water comes in I'll blame you . . .
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 10:28:52 am
Is it practical to consider infilling the ex-pond pit with clay?

Well you see it is over 7ft deep

'kin ell :o

that'll be a "no" then
Indeed. Getting in and out requires a rope hung from one of the 3"x5" steel beams that are handily overhead.
Title: Re: Getting through 12" of concrete
Post by: jogler on May 12, 2014, 10:39:47 am
This was a pond?
More likely a rocket launching silo or a nuclear waste shaft ::-)
Title: Re: Getting through 12" of concrete
Post by: Woofage on May 12, 2014, 10:51:18 am
Use it as a rain water store?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 10:54:03 am
For the entire neighborhood?  It hold about 17 000 litres and takes up over a 1/4 of the garden.
Title: Re: Getting through 12" of concrete
Post by: rafletcher on May 12, 2014, 11:11:14 am
You should be able to dig a soak away at the side of the pond liner avoiding the clay.

Which soakaway would have to be deep enough to penetrate the clay layer?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 11:19:59 am
I don't think it would need to - the clay layer is quite a long way down, possibly below the general water table. I just need drainage that will stop the whole thing from filling up with water.

Will measure up the overflow pipe (which actually goes to the lowest point in the pond) to see how big a pump I can feed down it - from memory, the pipe has an 8" internal diameter.
Title: Re: Getting through 12" of concrete
Post by: Vince on May 12, 2014, 11:22:19 am
Presumably the whole garden isn't under water so the clay layer is limited to either the vicinity of the pond or part of the way through the current depth of the pond. From just below ground level it would also be possible to pipe the water away to the normal land drain, no pumps or sumps needed.

X-posted with mrcharly.
Title: Re: Getting through 12" of concrete
Post by: Jaded on May 12, 2014, 11:24:04 am
Was it a swimming pool?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 11:39:30 am
We semi-seriously discussed using it as a swimming pool. There is a concrete pit (4ftx12ftx3ft) adjacent to it with all pipework (and power) needed for a filtration system. I was up for making it a salt-water pool. However everyone else would demand heating.
The steel posts and beams around this (I think the pond builder was going to make a pergola and had access to free steel + a welder) would allow easy construction of a diving deck. Just need to board it, add a ladder and done. My second suggestion of a sundeck was also vetoed, I don't know why. One of the children wanted a rope slide from their bedroom window.

Title: Re: Getting through 12" of concrete
Post by: CommuteTooFar on May 12, 2014, 02:15:03 pm
Perhaps this 'pond' is a construction to prevent your house subsiding into a small sinkhole.  :demon:
Title: Re: Getting through 12" of concrete
Post by: Tim Hall on May 12, 2014, 02:28:15 pm
Cracked it. It's a retractable swimming pool.  Are any of the wall lights indoors suspiciously wobbly? Do the eyes in portraits light up when the phone rings? Do you have a row of palm trees controlled by hydraulics?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 02:38:51 pm
Cracked it. It's a retractable swimming pool.  Are any of the wall lights indoors suspiciously wobbly? Do the eyes in portraits light up when the phone rings? Do you have a row of palm trees controlled by hydraulics?
Don't be ridiculous. This is Yorkshire.

There are three ceramic ducks on the wall that seem to rotate. In the living room there is a beer pump handle that isn't connected to a keg.
Title: Re: Getting through 12" of concrete
Post by: asterix on May 12, 2014, 04:03:10 pm
So you are going to fill it with sand and rubble you say?

My suggestion is that you do precisely that. As you fill it with the sand and rubble, go over it with a whacker every foot depth to get it nice and firm  until it is level filled to within say 12 inches of the rim (you'll want a nice strong platform).  Blind the surface with sand, lay a DP membrane overall then level fill with concrete.   It probably will fill with water underneath the 'raft' so you might provide a bit of overflow pipe or else just let if go where it will.   

Sorted.
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 04:07:01 pm
So you are going to fill it with sand and rubble you say?

My suggestion is that you do precisely that. As you fill it with the sand and rubble, go over it with a whacker every foot depth to get it nice and firm  until it is level filled to within say 12 inches of the rim (you'll want a nice strong platform).  Blind the surface with sand, lay a DP membrane overall then level fill with concrete.   It probably will fill with water underneath the 'raft' so you might provide a bit of overflow pipe or else just let if go where it will.   

Sorted.
Overflow to where?

I probably wasn't clear; MrsC wants this converting to a sunken seating area - sunken by about 3ft below ground level at the lowest. So water will enter and needs to be given a route out.

It's possible that I could drill holes in the sides and insert drainage pipes. I'll be investigating that at sometime.

Still, I need to remove water from the main structure, or it will just stink. Stagnant water with lord knows what small debris etc. ugh.

Title: Re: Getting through 12" of concrete
Post by: asterix on May 12, 2014, 04:17:18 pm
I'd a similar problem at the back of our barn. A bit of rain and we got a lake plus a stream flowing through the building.  Unfortunately it is solid rock and there is nowhere for the water to go. It did seep through it very slowly, took over a week to go down much.

First I retiled the back slope letting all the bust tiles fall in the pit above the solid rock.  Only c.45cm deep probably. Then I put guttering up so the roof water could flow away.  Finally I put geotextile over the tile layer and topped it with soil seeded with grass.  That was a few years ago and not even torrential rain can make the ground soggy.  The inside of barn is lovely and dry too.

In another area where I left rock exposed I noticed it became porous after a very cold winter with long periods c -11°C.  Guess frozen water cracks exposed rock.
Title: Re: Getting through 12" of concrete
Post by: andyoxon on May 12, 2014, 06:40:03 pm
I was surprised - excavators (mini diggers) not too pricey per day (£70)...  http://www.tvehireandsales.co.uk/DIGGERK8.asp?Product_ID=63&ProductType_ID=9&ProductCat_TypeID=16
Mind you, not sure it'd have enough reach down (with drill rather than bucket) for 7ft depth, or power for 12" concrete.   
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on May 12, 2014, 08:37:18 pm
plus I'd have to lift it over a 9ft wall to get it into the garden.
Title: Re: Getting through 12" of concrete
Post by: jsabine on May 12, 2014, 09:56:06 pm
You can get folding diggers (http://www.ukminidiggerhire.co.uk/mini-diggers.html) for confined spaces ...

(Tracks move under the body of the machine to let it get through a gap as narrow as a standard doorframe.)
Title: Re: Getting through 12" of concrete
Post by: Jaded on May 12, 2014, 10:11:31 pm
plus I'd have to lift it over a 9ft wall to get it into the garden.

Get a digger. Knock a whole in the wall with it.  :thumbsup:
Title: Re: Getting through 12" of concrete
Post by: fuzzy (retd.) AAGE on May 28, 2014, 10:10:25 am
A couple of yeras ago I removed a 12 ft by 6 ft concrete slab from the front of Fuzzy Towers. I hired an electric breaker for the task similar to this  (http://www.eroshire.co.uk/breaker-heavy-duty.html) and for a similar cost.

It stated up to about 6" of concrete but some bits were thicker. I'm sure you could do the job you need with this type of kit.
Title: Re: Getting through 12" of concrete
Post by: drossall on May 28, 2014, 11:04:40 pm
According to a programme the other night, you need one of these (http://en.wikipedia.org/wiki/Tallboy_%28bomb%29).
Title: Re: Getting through 12" of concrete
Post by: Paul on February 08, 2019, 01:35:18 pm
I found this thread while looking for a different answer (drilling some small holes into a concrete floor), but now I need closure.

How did you resolve this? Was the answer 'more concrete'? Or to move? Or did you decide that, actually, Mrs C was the problem?
Title: Re: Getting through 12" of concrete
Post by: Cudzoziemiec on February 08, 2019, 02:38:59 pm
I found this thread while looking for a different answer (drilling some small holes into a concrete floor), but now I need closure.

How did you resolve this? Was the answer 'more concrete'? Or to move? Or did you decide that, actually, Mrs C was the problem?
If there weren't bones under the concrete before, there are now?  :o

Or did it turn out to be a portal to another dimension? A lost world of prehistoric creatures ordinaries and boneshakers?
Title: Re: Getting through 12" of concrete
Post by: mrcharly-YHT on February 11, 2019, 03:54:39 pm
I found this thread while looking for a different answer (drilling some small holes into a concrete floor), but now I need closure.

How did you resolve this? Was the answer 'more concrete'? Or to move? Or did you decide that, actually, Mrs C was the problem?
Sorry, didn't see your reply.

I drilled about 30 holes through the concrete, with a large SDS drill (40mm bit about 400mm long). Filled bottom 3ft with rubble. Conveniently a house up the road was demolishing stuff, so I barrowed away a load of their rubble. Covered that with a garden mesh. Then barrowed in sand; 4 dumpy bags of the stuff.

Never got round to building the steps down to this.
Title: Re: Getting through 12" of concrete
Post by: Paul on February 11, 2019, 09:24:56 pm
Well done  :thumbsup:
Title: Re: Getting through 12" of concrete
Post by: Andrij on February 12, 2019, 08:42:38 am
Too late now, but I'm surprised no one suggested thermite...
Title: Re: Getting through 12" of concrete
Post by: Paul on February 12, 2019, 12:44:38 pm
Thermite was passed over (https://yacf.co.uk/forum/index.php?topic=82364.msg1683492#msg1683492)
Title: Re: Getting through 12" of concrete
Post by: fuzzy (retd.) AAGE on February 13, 2019, 09:22:52 am
I found this thread while looking for a different answer (drilling some small holes into a concrete floor), but now I need closure.

How did you resolve this? Was the answer 'more concrete'? Or to move? Or did you decide that, actually, Mrs C was the problem?
Sorry, didn't see your reply.

I drilled about 30 holes through the concrete, with a large SDS drill (40mm bit about 400mm long). Filled bottom 3ft with rubble. Conveniently a house up the road was demolishing stuff, so I barrowed away a load of their rubble. Covered that with a garden mesh. Then barrowed in sand; 4 dumpy bags of the stuff.

Never got round to building the steps down to this.

Some millenia hence archeology students are going to have a field day working you out ;D