Complex groundworks - Options?

[Tony K]

Hi all,

Commencement of our new build is being delayed as I am struggling to get a groundworks firm to take on the footings. It's a fiddly little job....

 

I have no direct access to the road (long footpaths from the road lead you there instead).

The land must be reduced by about 60cm all over, equating to about 100 cubic metres of muck is to be taken out and away. 

Tree roots must be protected, so piles are to be used with a raft on top. The engineers design presumes 46 piles, each about 6m deep (soil test to confirm).

The reinforced slab will be poured on top of void formers to create space for heave etc under the slab.

Oh, and the slab is split level.

 

All of this can be achieved. A range of smaller diggers can access the site. Track dumpers can be used to carry the muck away to the roadside for collection. A mini-piling rig can access the land and install the piles. Setting out the formwork is fairly standard stuff. A pump can be used to get cement to site from the road.

 

But.... It's obviously more of a headache than most GW firms are used to, and it's putting off the relatively small number of local contractors who could do the whole job as one contract. 

 

My question is, how feasible is it for me to break this down into separate parts? I am thinking of hiring a mini digger and track dumpers with drivers to lower the site, then hire a piling contractor direct to do the piles, then a groundworker to cast the slabs. I would perhaps need to hire a surveyor to set it out too. 

 

Has anyone had to attack groundworks this way? 

Would it likely affect warranty?

Is it feasible to split the work up this way?

 

Thanks

[Big Jimbo]

I don't see why not. I know some piling companies that won't touch unless they do the lot, and some that are only interested in doing the piles. I see no reason why with the use of a lazer level you can't do atleast the ground reduction. Most tree roots, are in the top meter of ground. If you have to reduce the site by 600mm how are you going to protect the roots ? Don't say hand dig.

[Temp]

I don't envy you.

 

Are they public footpaths?

 

Some things also appear incompatible with each other such as..

 

3 minutes ago, Tony K said:

The land must be reduced by about 60cm all over.... snip...  Tree roots must be protected

 

Normally to protect trees you can't dig at all.

 

5 minutes ago, Tony K said:

My question is, how feasible is it for me to break this down into separate parts? I am thinking of hiring a mini digger and track dumpers with drivers to lower the site, then hire a piling contractor direct to do the piles, then a groundworker to cast the slabs. I would perhaps need to hire a surveyor to set it out too. 

 

I think that's probably the best route but you will probably need something bigger than a mini digger. Hammer in some posts and use a water level or laser to put marks on them, then tell them to excavate until its ?cm below the top of the posts. When level set out for the piling. Perhaps pay the engineer to make a few site visits to check before piling and before pouring?

 

I used a hired dumper truck to transport ready mix concrete around our site which worked ok provided you drove slowly.  Perhaps work out how many trips up and down the path you would have to make to move 100 cubic meters. Are neighbours going to complain?

 

The problem might not be digging but loading the muck away lorries. Is there space near the road to put a massive pile of dirt so you can use same digger to load the muck away lorry when it come to collect?  

 

How long are the paths? Can you pump concrete that far?

 

[Tony K]

2 hours ago, Temp said:

1. Are they public footpaths?

2. Normally to protect trees you can't dig at all.

3. Perhaps work out how many trips up and down the path you would have to make to move 100 cubic meters. Are neighbours going to complain?

4. The problem might not be digging but loading the muck away lorries. Is there space near the road to put a massive pile of dirt so you can use same digger to load the muck away lorry when it come to collect?  

5.How long are the paths? Can you pump concrete that far?

 

 

1. Open to the public, but not Council maintained. The path is the access to our house and the site, as well as to a few other neighbouring houses.

2. I should have been more specific. The slab is split level, the higher portion bridges over the tree roots. The rest of the site is reduced by 60cm.

3. Depends on how much muck the dumper holds I suppose. They seem to be able to handle up to 1 tonne, which I guess is more than a square metre of earth (?). I guess I'm looking at less than 100 trips. The neighbours are OK, and I'll make good any rutting on the path. Even if they are grumpy I've got right of access. 

4. There is space. I will put down boards on a wide verge at the end of the path and section an area.

5. Path is 80m long. I believe I can pump cement that far, but will check. 

 

Thanks for the comments and advice!

[Temp]

Sounds like it's doable. 

 

We have a public footpath near and across our land and someone pointed out you aren't allowed to drive vehicles over a public footpath unless you have a right of way. It didn't cause us too many issues in the end, although footpath officer said he wouldn't divert it to a new route until the grass seed we had laid had grown. So we turfed it and told him it grew overnight.

Edited March 5, 2020 by Temp

[Russell griffiths]

Instead of piles of dirt for collecting you could do what we had to do in London, put a couple of skips where the dirt is to go, then when the grab lorry comes get him to empty the skips, and just refill them. 

this solves lots of problems, it saves muck getting washed onto the highway, keeping it all tidy and neighbours a bit happier, then as you finish just get the loaded skips removed. 

 

You are probably better off getting multiple trades in to do each bit

if you get one company in and your site looks like an agro job they will do one of two things, not quote or price it very high. 

With multiple trades the bit they will do probably won’t seem too bad so they will do it move on and be thankful that they didn’t get asked to price all of it. 

 

 

[Tony K]

2 hours ago, Russell griffiths said:

Instead of piles of dirt for collecting you could do what we had to do in London, put a couple of skips where the dirt is to go, then when the grab lorry comes get him to empty the skips, and just refill them. 

this solves lots of problems, it saves muck getting washed onto the highway, keeping it all tidy and neighbours a bit happier, then as you finish just get the loaded skips removed. 

 

You are probably better off getting multiple trades in to do each bit

if you get one company in and your site looks like an agro job they will do one of two things, not quote or price it very high. 

With multiple trades the bit they will do probably won’t seem too bad so they will do it move on and be thankful that they didn’t get asked to price all of it. 

 

 

 

Do you know what..... I had discounted the idea of a skip for muck storage as it was too small and would fill too soon. Didn't even think to get a second one! What a plum I am!

As you rightly say, the last two skip loads can be taken by the skip firm too. 

 

You are spot on about groundworks firms. Its all no quote for ages, and then after endless chasing I get a sky high price.

 

Am now quite looking forward to splitting this up and getting stuck in myself. I have recently seen a type of track dumper that has a lifter shovel on the front, which would be very useful. That way the digger driver can get on with the digging etc and not waste time loading up the track dumper every time in returns from the skips. This is the type of thing I mean:

 

 

Thanks for all the advice.

Edited March 5, 2020 by Tony K

[Moonshine]

17 minutes ago, Tony K said:

Do you know what..... I had discounted the idea of a skip for muck storage as it was too small and would fill too soon. Didn't even think to get a second one! What a plum I am!

As you rightly say, the last two skip loads can be taken by the skip firm too. 

 

And if two skips are too small per grab lorry load or how quick you get it out, think bigger!

 

How about hiring a roll on/off hook skip, there are doors are the rear but when full not sure how you would get stuff in

 

 

There are lower sided 15-20 cubic yard RoRo Skips

 

Edited March 5, 2020 by Moonshine

[Ferdinand]

You may getaway with fencing of the footpath if your drive is wide enough.

 

If you can put knocker posts in 80m should be pretty quick to do a post and rail or PST and tensioned wire fence, not expensive and you can reuse it all later if you take it out again when done.

 

Ferdinand

[Patrick]

@Tony K

Currently doing very similar thing on my site. No road access. Footpath to site with 100m to next road (approx). I did break it down into several jobs. I am avoiding a slab for the muckaway trouble it creates. You could think about a block and beam, saves a bit of dirt shifting.

Get in touch if you need a good piling contractor that works out solutions rather then come up with requests what you have to provide to them (had a fair few discussions with piling guys that requested a unseen list of specifics before starting the job.)

[Temp]

5 hours ago, Tony K said:

This is the type of thing I mean:

 

Can you go bigger? Those may carry 1000kg weight but the volume capacity is typically 250-400L depending on model and if the soil is level or heaped. If you really have 100m^3 to move that would be 200-400 trips.

[Tony K]

6 hours ago, Moonshine said:

 

And if two skips are too small per grab lorry load or how quick you get it out, think bigger!

 

How about hiring a roll on/off hook skip, there are doors are the rear but when full not sure how you would get stuff in

 

 

There are lower sided 15-20 cubic yard RoRo Skips

 

 

My only observation about the green one is whether I could drive the tracked dumper actually inside it, or would the floor of it split under the weight? If I can't drive into it then I couldn't use most of the area inside the skip as I couldn't reach it. The blue one might not hold as much but most track dumpers come with a lift up-and-over function to get stuff into skips, so would work well in that respect.

 

1 hour ago, Temp said:

 

Can you go bigger? Those may carry 1000kg weight but the volume capacity is typically 250-400L depending on model and if the soil is level or heaped. If you really have 100m^3 to move that would be 200-400 trips.

 

Yeah I had thought of that. The access path is about 90cm at its narrowest, so I'd be looking for a dumper quite long and thin, and also with a shovel function ideally. 

 

5 hours ago, Patrick said:

@Tony K

Currently doing very similar thing on my site. No road access. Footpath to site with 100m to next road (approx). I did break it down into several jobs. I am avoiding a slab for the muckaway trouble it creates. You could think about a block and beam, saves a bit of dirt shifting.

Get in touch if you need a good piling contractor that works out solutions rather then come up with requests what you have to provide to them (had a fair few discussions with piling guys that requested a unseen list of specifics before starting the job.)

 

Thanks, I will contact you.

[Russell griffiths]

6 hours ago, Moonshine said:

 

And if two skips are too small per grab lorry load or how quick you get it out, think bigger!

 

How about hiring a roll on/off hook skip, there are doors are the rear but when full not sure how you would get stuff in

 

 

There are lower sided 15-20 cubic yard RoRo Skips

 

No good for soil as they have a weight limit. 

[Tony K]

3 minutes ago, Russell griffiths said:

No good for soil as they have a weight limit. 

 

Both of those options have weight limits do they?

Sounds like its back to good old skips.

[Russell griffiths]

Forget that silly loading dumper, only any good at loading materials, will be about as much use as a chocolate teapot for loading soil. 

They also track very slowly. After 400 loads you will be very unhappy. I would have 2 dumpers running the soil out and one digger, you will be surprised how much you can shift with a 1-5 ton machine. 

 

Have you calculated the soil bulking up as 100m is not a lot. 

[Tony K]

1 hour ago, Russell griffiths said:

Forget that silly loading dumper, only any good at loading materials, will be about as much use as a chocolate teapot for loading soil. 

They also track very slowly. After 400 loads you will be very unhappy. I would have 2 dumpers running the soil out and one digger, you will be surprised how much you can shift with a 1-5 ton machine. 

 

Have you calculated the soil bulking up as 100m is not a lot. 

 

Do you have an example of a 1-5 tonne machine you can point me towards at all?

Not sure what you mean by calculating the soil bulking up? Whats that mean then?

Thanks

[Russell griffiths]

16 minutes ago, Tony K said:

 

Do you have an example of a 1-5 tonne machine you can point me towards at all?

Not sure what you mean by calculating the soil bulking up? Whats that mean then?

Thanks

Oops so that means you haven’t done it. 

You have a hole to dig it’s 1m x1m x1m so you would expect to excavate 1msquared. 

If you imagine what you dig out is now loose and fluffy not compacted into a 1m block so it now has gaps full of air, your 1m hole has now produced 1.4m of spoil. 

This varies depending on soil type. 

As a safe margin if you think you will dig out 100m allow 40-50% for bulking. 

[Tony K]

8 minutes ago, Russell griffiths said:

Oops so that means you haven’t done it. 

You have a hole to dig it’s 1m x1m x1m so you would expect to excavate 1msquared. 

If you imagine what you dig out is now loose and fluffy not compacted into a 1m block so it now has gaps full of air, your 1m hole has now produced 1.4m of spoil. 

This varies depending on soil type. 

As a safe margin if you think you will dig out 100m allow 40-50% for bulking. 

 

Ah, yes then in that case I have thought of soil bulking up!

[ProDave]

Is there anywhere on the site to use the excavated soil?  I used all ours to raise the ground level of the lower parts of the site, no muck away at all.

[Temp]

2 hours ago, Tony K said:

The access path is about 90cm at its narrowest, so I'd be looking for a dumper quite long and thin, and also with a shovel function ideally. 

 

I agree with Russell. It would take too long picking up dirt with the shovel. I reckon much quicker to get the digger to load it/them and you could probably fill them better as well.

 

Is there no way to make it wider even temporarily? The thing I hired was more like a Thwaites 1 ton dumper...

 

http://www.thwaitesdumpers.co.uk/PDFLibrary/Sales lit UK/201 - 1 Tonne Hi-Tip - UK.pdf

 

 

 

 

  

 

 

[ProDave]

I once saw what looked like a pretty standard small dumper with a back hoe on it.  At first I thought what a neat idea, until I realised there was no way it could self load.

[andyscotland]

If it's that narrow, no idea if it would be viable cost-wise over your distance but have you explored conveyor belts? You could just have the digger dump the muck on at one end and spit it out into the skip/whatever at the other, might be quicker than all the back and forward. You'd need multiple units, don't know how that compares to two dumpers + operators.

[Tony K]

18 minutes ago, ProDave said:

Is there anywhere on the site to use the excavated soil?  I used all ours to raise the ground level of the lower parts of the site, no muck away at all.

 

Nope. The whole site has to be reduced. 

 

15 minutes ago, Temp said:

 

I agree with Russell. It would take too long picking up dirt with the shovel. I reckon much quicker to get the digger to load it/them and you could probably fill them better as well.

 

Is there no way to make it wider even temporarily? The thing I hired was more like a Thwaites 1 ton dumper...

 

http://www.thwaitesdumpers.co.uk/PDFLibrary/Sales lit UK/201 - 1 Tonne Hi-Tip - UK.pdf

 

 

I would investigate the usefulness of the shovel as part of my planning. I agree that it looks like it might not cope well with clay soil, but I'll check. If it can cope then I have the option to get the digger to do his bit and then go, leaving me to it with the shovel/dumper. Less cost for the digger that way. I will find out for sure that the shovel could cope though.

 

Path cannot be made wider, its more like an alleyway really with fences all down both sides. I'll be looking around for the biggest, deepest, strongest dumper that fits. 

 

3 minutes ago, andyscotland said:

If it's that narrow, no idea if it would be viable cost-wise over your distance but have you explored conveyor belts? You could just have the digger dump the muck on at one end and spit it out into the skip/whatever at the other, might be quicker than all the back and forward. You'd need multiple units, don't know how that compares to two dumpers + operators.

 

My instinct is that conveyors would be hugely expensive, but I'll check. 

 

Thanks

[Oz07]

No way would that dumper loader pick up compacted or sticky material. Its more for loading stone, sand or gravel tipped loose

[Russell griffiths]

If it has fences down the sides you will want to screw plywood to protect them, or price in to replace them afterwards.