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Posted: Sat Jun 21, 2014 5:02 pm
by r896neo
Personally I think its a bad idea not to have a hardcore sub base under a concrete drive. A path would be fine but why take the risk with a driveway.
It looks like there is more excavating to do anyway as the concrete needs to be at least 100mm thick with 125 probably being a better bet on a drive.
Are you sure this guy is up to the job? Concrete as a finished surface is a very easy thing to get wrong. I would want to see previous finished concrete paths or drives he has done.
Posted: Sat Jun 21, 2014 11:03 pm
by digerjones
why has he took the old drive up. it would have been better to leave the drive in till hes finished the garage. it needs to be dug out at least 9/10'' from finished floor level.
good luck
Posted: Sun Jun 22, 2014 8:36 pm
by Flotsam
Thanks for the information so far. I think the reason the driveway was taken up was because a minidigger was used to dig the footings for the outbuilding and to break up the existing concrete drive. The guy is pretty amiable, but I just want to make sure I am more informed so I can counter anything I may not agree with. Work is stopping for a few days, so am trying to gather information. The clay surrounding the house is very thick and was what the original concrete driveway was laid on, although some cracks had developed (mind you it had probably been down since the house was built). Is there are test for the stability of the clay?
At the moment, one of the reasons for not going lower is the gas pipe. Is there a standard procedure for dealing with this e.g. would you just place hardcore/sand round, to protect it? Should it be covered by something e.g. surrrounded by plastic pipe and embedded in the concrete?
Posted: Sun Jun 22, 2014 9:13 pm
by mickg
don't take it the wrong way but like other have said the correct way would be to excavate the foundations, remove the existing concrete driveway and the clay down to the correct depth and then to lay the sub base for the new driveway, this way means both the builder and your family are not walking through dirty clay and walking it everywhere mainly on your carpets looking at the state he has left the front door area - what are you suppose to do balance yourself on a 125mm floor board he is using as a plank whist carrying the shopping in doors 
he could have just dug out for the foundations and completed the work at the rear then to of removed the driveway including any surplus building materials or waste left over from the rear building work
how he has left the driveway at the moment means he still has to bring the mini digger back to remove the surplus clay down to the correct level, or he has no intention of removing it and was aiming on pouring the new concrete drive on top of what he has left as per the photos you posted above - if this is the case then it is not the correct way
everyone can operate in different ways but the way this guy has approached your work is not what I would call the correct way whist keeping the site spotlessly clean and above all SAFE for everyone
Posted: Sun Jun 22, 2014 10:16 pm
by lutonlagerlout
^^
needs to be dug out at least 225mm below finish
125mm type 1 wacked in to levels then minimum 100MM of c30 concrete (pavemix) laid to falls tamped brushed and arris troweled
LLL
Posted: Sun Jun 22, 2014 11:29 pm
by sy76uk
would he need any re-bar in with that?
Posted: Tue Jun 24, 2014 11:58 am
by msh paving
^^^^ no need , maybe a small mesh but cant see a need
MSH 
Posted: Wed Jun 25, 2014 8:16 am
by GB_Groundworks
A layer of 142 50mm from the top wouldn't do any harm and help with plastic cracking.
I wonder if there will be any expansion material next to the building, crack formers or contraction joints cut into 24hrs hours after pouring.
Posted: Wed Jun 25, 2014 4:54 pm
by lutonlagerlout
I would say 2 hopes Giles and bob is outta town
LLL
Posted: Wed Jun 25, 2014 8:43 pm
by msh paving
^^^^^^
Posted: Wed Aug 13, 2014 7:19 pm
by Flotsam
Just got the feed for the builder's horses- he has skipped town! Week 12 of the job and think I drew the short straw re: builders and need to get a few more quotes for the driveway and some paving flags at the rear of the house.
Originally the driveway was concrete which had been poured straight onto the clay base you can see. The builder was under the impression that as it had been down for so long then not much would be needed as a base (MOT1?)- "just a few stones whacked into it". Although, from the posts above it looks like 125mm type 1 would be best.
Could you please help answer the following so I can arrive at a spec to give re: quotes?
(1) Linear drain will be placed alongside the house wall- should it fit flush against the wall (I think there will be a small gap so the linear drain lines up with the hoppers/gullies, so it won't) or should there be some flexible filler board+sillicone and a thin strip of concrete to fill it?
(2) The driveway height will be 2 courses below the dpc. On the neighbour's side, the concrete was going to be edged with some pin kerb but I don't think this will extend far enough down into the ground. Would the kerb easily be kicked away from the concrete/what else would be better for the edging?
(3) The spec he suggested was, at the top of the driveway (where the car is parked) 150mm concrete with a single sheet of rebar to support the car at the beginning of the drive, 100mm concrete along the rest of the driveway with no rebar- foot traffic only. Does this sound ok?
(4) A concrete pathway in front of the bay window is to be replaced- nothing will be put under it, 100mm concrete would be poured straight onto the exposed clay.
(5) I suggested, from what I had read, that 12mm filler be used to create expansion gaps with silicone (30mm) on top, roughly every 3-4m.
(6) Would a layer of DPM be needed along the length of the driveway?
(7) The driveway was to be formed in sections. Will steel dowels be needed to join each section? How should this done?
(8) Driveway crossfall towards linear drain is 1:60. The concrete is be brushed and trowelled.
I have found this forum and site to be really useful and did use it to inform my discussions with the 'builder'. Thanks for the information provided previously and for any replies.
Posted: Wed Aug 13, 2014 8:14 pm
by GB_Groundworks
just get someone who knows what they are doing in to do it, pay cheap pay twice
randomly sticking mesh in concrete does no good, its used in specific ways depending on the stress and strains, light mesh in the top to stop cracking, large mesh in the bottom of the slab for strength
for normal everyday car use 100mm with a layer of a142 mesh is fine(assumes good ground and 100-150mm of mot well consolidated , 3.5 ton vans etc 150-200mm
yes you need dam all the way to stop the concrete loosing to much water into the ground or being attacked by minerals etc in the ground
no pour it one and cut contraction joint 25% of the depth within 24 hours of pouring, you can put some crack formers in if you want
id want a troweller and brushed finish as well
here this is on the main site
http://www.pavingexpert.com/concrete.htm
copyright the gaffer
Edited By GB_Groundworks on 1407957322
Posted: Tue Aug 19, 2014 7:05 pm
by Flotsam
Thanks GB, Thought I'd got someone in that knew what they were doing, before!
I have had specs from two local driveway comps, both said that they would put down 100mm concrete, 100mm hardcore, no dpm and no rebar. I asked both whether rebar should be used in the concrete under where the car will be parked and they said there is no need.
Does this sound ok from the people who know what they are doing?
Posted: Tue Aug 19, 2014 7:53 pm
by msh paving
you cant do a good job with no DPM under the concrete as the water will run out to quick before you finish it.
for a good job i would use 150mm of concrete, 1 layer of A252mesh 50mm from the bottom,you dont have to use mesh but it will make a far better job and stand the test of time.
You say driveway contractors but are they concrete people or just general paving men MSH
(Side of house)
(Driveway down side of house)
(Driveway entrance/exit)
('Pin' kerb? Showing proposed height of driveway)