WWilts

Demolition rubble disposal

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Posted (edited)

Demolition of garage.

 

Options

 

1) Crush (noisy for neighbours, crusher hire charge over £600 for 2 hours). Use the hardcore on site

 

 or

 

2) Disposal, followed by purchase of hardcore. About 22 tons can be used within footprint

What would you do?

Edited by WWilts

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32 minutes ago, WWilts said:

What would you do?

Maths , how many muck away lorry @ £xxx + 22 ton hard-core delivered add the 2 together minus £600 +labour ÷ which method is the path of least resistance = answer 👍

 

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I have the same question, but how do I calculate how much hardcore we will need.

 

I used to be good at maths, but then I got old 

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1 minute ago, LSB said:

how do I calculate how much hardcore we will need

Footprint area in sqm x 0.35m = (roughly) cu m of hardcore for footprint
Can use for any area, to get ballpark figure

 

1 cu m of crushed concrete hardcore = 0.7 tons

 

Once you work out the cu m required, (say x) you divide by 0.7 to get the number of tons you require

 

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Area m2 ,multiplied by depth ,will give you m3 then check how much a m3 of chosen materials weight. 

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3 minutes ago, WWilts said:

Footprint area in sqm x 0.35m = (roughly) cu m of hardcore for footprint
Can use for any area, to get ballpark figure

 

1 cu m of crushed concrete hardcore = 0.7 tons

 

Once you work out the cu m required, (say x) you divide by 0.7 to get the number of tons you require

 

 

so, we had to dig out the floor of the barn which was 6" concrete then sand / rocks to lower the floor.  We used the sand / rocks for driveway and to fill a big hole and piled up the concreate.  Do you think that what we took out should roughly equal what we put back.

Sorry to highjack your question.

 

What we are considering, because it is 240 sqm is getting in someone to do the crushing, this will cost about 2k, but we can't possibly crush it all ourselves in 2 hours (cost same as yours) so in the end the cost won't be that much different.  I haven't got the cost for a grab lorry yet, but someone on here said about £300, but I'm not sure how much that will be for.

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23 minutes ago, WWilts said:

1 cu m of crushed concrete hardcore = 0.7 tons

I'd check that I'd say your closer to double that weight. Especially if  to see small for backfilling floors

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Grab lorrys are typically 18.5 tonnes payload 

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Good rule of thumb for type 1 is 2 tonnes per m3 , some lighter, limestone i think is 2.2 .

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As Roman said, concrete crusher run is typically 1.6t per cube depending on how much dust is in it.

biggest mistake most people make with excavations is not factoring in how much expansion occurs when soil is removed. 1 cube in the ground fills almost 2 cube in a truck or skip

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19 hours ago, Buzz said:

Good rule of thumb for type 1 is 2 tonnes per m3 , some lighter, limestone i think is 2.2 .

 

sorry to be dim, but is this what you are saying that you need ?

 

an example from one of my sheds.

 

Width 3.29 * Length 3.62  =  11.91 sqm, * 0.35 = 4.17 = cubic m 

 

So, I have the concrete from this in big lumps, will I get 4.17 * 0.7 when crushed = 2.92

 

And, will I need 4.17 * 2(ish) to put back of hardcore = 8.34

 

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Not exactly. 

when you dig up rock or soil it bulks up with jagged edges and lots of air between so the density is reduced.

For gravel or pure sand it will not bulk much, but the more jagged the product the more air is between the lumps, 0.7 is a decent estimate for concrete or clay..

So 1m3 of solid concrete becomes 1.4m3 of pile of concrete. If you send it away you fill the lorry with 0.7 concrete and 0.3 air.

 

They or you crush it, and the density varies a lot depending on if it is all one size or there are smaller bits and dust to fill the gaps.

If completely graded, like type 1 stone, it is very much denser. Then if you compact type 1 well, it is almost like concrete or rock again.

 

If you crush on site to put back the same volume, you will have surplus hardcore.

If you buy  it in, you can have a choice of qualities, and densities....ask the supplier what the conversion is.

You pay them by the ton, and use the conversion between 1.8 and 2.2 ish to convert to m3 you need.

 

The crushing process can vary in quality, and ethical approach, I have seen earth being mixed in, and have had wire and plastic in it.

How did a toilet seat get through the crusher and the sieve? 

I have rejected a load for being full of mud (mixed thoroughly) and had no argument back from the supplier.

Conversely there are very thorough suppliers, and it is as good as virgin stone.

 

answer? diy crushing you will bulk up and have surplus.

diy or send away and buy back? you must do the sums. My hunch is crush on site but crush it very thoroughly. Some might have to through twice. 

Have a hose to hand to keep the dust down, and some beers for the neighbours.

 

BUT  !!!!!! are you sure you need to take it out/ why can you not leave it there as a very good sub-base?

More to say on that subject if required, but I have observed that most(?) consultants say to take it out and then put stone in, but it is not their money.

 

 

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2 hours ago, saveasteading said:

Not exactly. 

when you dig up rock or soil it bulks up with jagged edges and lots of air between so the density is reduced.

For gravel or pure sand it will not bulk much, but the more jagged the product the more air is between the lumps, 0.7 is a decent estimate for concrete or clay..

So 1m3 of solid concrete becomes 1.4m3 of pile of concrete. If you send it away you fill the lorry with 0.7 concrete and 0.3 air.

 

They or you crush it, and the density varies a lot depending on if it is all one size or there are smaller bits and dust to fill the gaps.

If completely graded, like type 1 stone, it is very much denser. Then if you compact type 1 well, it is almost like concrete or rock again.

 

If you crush on site to put back the same volume, you will have surplus hardcore.

If you buy  it in, you can have a choice of qualities, and densities....ask the supplier what the conversion is.

You pay them by the ton, and use the conversion between 1.8 and 2.2 ish to convert to m3 you need.

 

The crushing process can vary in quality, and ethical approach, I have seen earth being mixed in, and have had wire and plastic in it.

How did a toilet seat get through the crusher and the sieve? 

I have rejected a load for being full of mud (mixed thoroughly) and had no argument back from the supplier.

Conversely there are very thorough suppliers, and it is as good as virgin stone.

 

answer? diy crushing you will bulk up and have surplus.

diy or send away and buy back? you must do the sums. My hunch is crush on site but crush it very thoroughly. Some might have to through twice. 

Have a hose to hand to keep the dust down, and some beers for the neighbours.

 

BUT  !!!!!! are you sure you need to take it out/ why can you not leave it there as a very good sub-base?

More to say on that subject if required, but I have observed that most(?) consultants say to take it out and then put stone in, but it is not their money.

 

 

 

I would love to have left the floor, but as we cannot go up and had quite a lot of roof at 1.8m we had to go down.

What we have in the remove / crush pile is pretty much solid 6"+ thick concrete.

Obviously, there is mud on the rubble, but not mixed in.

This little lot is a side pile that is too heavy for our digger to lift and put in the main pile.

 

 

rubble2.thumb.jpg.888180e775e68eadf1a16b605653506f.jpg

 

 

We have this currently from approx 20m * 4m = 80m and will ultimately have about 200 sqm.

There is a small area which is already low enough as the roof is sloped.

 

The plan is then to put in mot type 1 sort of layer, sand, dpm etc. etc. to raise the floor back up to 20cm lower than where we started.

After removing the rubble we dug out old sand / mud and stones all of which were used or stored elsewhere.

Most of it has become the build drive as the deliver lorries were getting stuck coming up the slope.

 

With so much crushing it ourselves is probably not feasible.

But when we bought our house 20 years ago there we many concrete pig sty's which were knocked down and crushed on site by a company.

The lot cost 14k, but we were able to then sell it all via a company (friend) and ended up a little in profit.

 

I have been very careful to remove the old DPM and any metal so I think it's fairly clean.

 

Ironically the person we know who will supply MOT type 1 if we need it will arrange to take this lot away, get it crushed and then sell it to people like us.

 

From the previous lot many of the houses in our village had some for driveways, house extensions etc.

 

We are aware that a lot of this is so solid that it will need a large crusher, the smaller Rhino that we looked to hire wouldn't touch it.

 

thanks for all your points I shall do some sums tomorrow.

 

 

 

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The amount of mud on your concrete is trivial. I was commenting on muck deliberately mixed through from a separate pile.

Likewise the odd bit of plastic and steel is to be expected, but not branches., toilet seats and areas of steel mesh.

 

Yes you send away good stuff, and unfortunately sometimes buy back a lesser mix. 

If in any doubt, ask the supplier if you can observe the crushing process.

It will help the price a lot if they can use the lorries both ways, ie delivery and collection, but that depends on having enough space.

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