Page 1 of 2
Posted: Sat Apr 21, 2012 1:04 pm
by lutonlagerlout
pricing another awkward job so this is one for you digger fellas
due to proximity of conifers some of the founds need to be 2400mm deep,some 1800 some 1500 and some at 1200
I dont mind hand digging but I know that this is way too deep for that
heres the crunch
the access is only 900mm
I have a feeling that there are machines that small but will they dig in clay and flint to 2400?
other options are piles and ring beam
or maybe a raft
what says the digger men?
thanks
LLL 
Posted: Sat Apr 21, 2012 1:15 pm
by DNgroundworks
A micro will not dig to 2.4 mtrs im pretty sure of that, 1.8 is the limit with a kubota U10. The kubota U17-3 is 990mm wide with a dig depth of 2.3 mtrs. most machines will be similar, im just familiar with kubota. The U series are higher speced than the kx series btw, in terms or reach etc.
Look like it could be the ring beam jobby? Or crane a 3 tonner in
Posted: Sat Apr 21, 2012 1:16 pm
by msh paving
tony most 1.5 ton m/c's will dig 1.8-2.2m but the 900mm is out off the question, my micro is 750 wide will dig 1.7ish maybe a tad more,most 1.5 ton are 1.3m wide,you may get a small drop hammer rig in a 900mm and then pile the job or as Giles said this week use a grundomat and pile 150mm with them ,I would suggest a raft is the way forward but im not a str. engineer MSH
Posted: Sat Apr 21, 2012 2:56 pm
by digerjones
msh paving wrote:tony most 1.5 ton m/c's will dig 1.8-2.2m but the 900mm is out off the question, my micro is 750 wide will dig 1.7ish maybe a tad more,most 1.5 ton are 1.3m wide,you may get a small drop hammer rig in a 900mm and then pile the job or as Giles said this week use a grundomat and pile 150mm with them ,I would suggest a raft is the way forward but im not a str. engineer MSH
think your wrong about the width of 1.5 minis, i've got 2 and sure they are just less than 1m and one of mine is 1.6ton.
tony if the access is tight but you have plenty of room in there you could get a micro in and reduce the dig before you start digging the footing.
Posted: Sat Apr 21, 2012 4:24 pm
by dig dug dan
tony, i spoke to some builders up the road on my estate doing a side two storey extension, on a house exactly the same as ours, next to mature oak trees.
The building officer asked them go to 2.4m. He told me it was cheaper to pile it.
One reason was the amount of cart away, the amount of concrete that had to go back in, and the time to do it all.
The piling company did it in a day
Posted: Sat Apr 21, 2012 4:30 pm
by lutonlagerlout
we have had fairly reasonable piling quotes in the past,around 3k for a small extension ,we then had to do the ring beam ourselves
problem is i just aint up for digging more than 1.2 unsupported,if it goes you are gone
i saw a trench 2.7m go 4 years ago and it went like a pistol shot,any man down there would have been dead and the concrete wagon had just pulled up
thanks for the advice ,i had considered craning a 3tonner over but at £650 + vat each way its a big lump straight on the job
LLL
Posted: Sat Apr 21, 2012 5:33 pm
by Pablo
Crane it thats what I've done in the past it'll surely be the cheapest way to do it and a local firm could do it way cheaper than that it's only a quick lift and should fit it in early before they head off to the next site. Even at day rate thats a huge price. Can you get access from other properties through a fence etc and use track mats to protect the ground
Posted: Sat Apr 21, 2012 5:41 pm
by dig dug dan
Crane it thats what I've done in the past it'll surely be the cheapest way to do it and a local firm could do it way cheaper than that it's only a quick lift and should fit it in early before they head off to the next site. Even at day rate thats a huge price. Can you get access from other properties through a fence etc and use track mats to protect the ground
by the time you have paid for the crane, machine, muck away, concrete in, re-inforcing + trench shoring, Piling WILL be cheaper
Posted: Sat Apr 21, 2012 5:53 pm
by lutonlagerlout
already rang around pablo,you pay for half a day even if the lift is only 20 minutes
TBH i dont like the idea of a 3 tonne machine going over someone's house,plus you still have a deep excavation to deal with
piles or raft it is for sure
thanks
LLL
Posted: Sat Apr 21, 2012 6:40 pm
by Pablo
Fair enough Tony how big are the conifers by the way becuase they're generally the shallowest rooting of all the trees it would be unusual to find anything more than fine fibre at .5m and below on even the 90ft+ ones so 2.4m seems beyond over kill.
Posted: Sat Apr 21, 2012 8:29 pm
by GB_Groundworks
maximum dig depth is ok but you never really dig at that say its 2.5m then realistically dig depth is 2.3 say as youve got a small working envelope
id mini pile it then 400x450 ground beam, our structural engineer says £30m linear metre for 150mm piles and then £300 mobilisation cost thent he ground beam
id definetly think pilling is your best option, ive done a few at 2.4 near tress and its a pain in a 3 ton, plus the amount of stuff you'll be getting rid off means the muck away costs will be more than pilling it.
Posted: Sat Apr 21, 2012 11:07 pm
by Al Jardin
From what planet do these building control people come from. I've heard many stories regarding deep foundations for buildings near non threatening trees. Then for another officer to come out and say 'it doesn't need to be that deep' after you've spent x over the top. I take it they're not retired builders.
Al
Posted: Sun Apr 22, 2012 9:23 am
by Mikey_C
excuse my ignorance but aren't you going to suffer with the same access problems for the piling machine?
Posted: Sun Apr 22, 2012 9:37 am
by Dave_L
Mikey_C wrote:excuse my ignorance but aren't you going to suffer with the same access problems for the piling machine?
No, that'll come in via helicopter.
Simples! 
Posted: Sun Apr 22, 2012 10:58 am
by Pablo
micropile machines are the same width as micro diggers but they're very long so getting through isn't the problem it's turning the corner that is.