depth of concrete

[BrokenBiker]

how deep do you need to go with concrete for a driveway?

would be holding a range rover sized 4x4 if it makes any difference and is on a slop that rises about 2 meters over a 12 meter length

 

[Shedendman]

6 inch min for your top course,but you got a hell of a lot work to do underneath it going by those specs,what are you laying it all on,grass or dirt bank?

 

[Shedendman]

Oh and it would have to be re-inforced ie mesh

 

[julianf]

My opinion -

You wont get a sound, one size fits all, answer off the internet, as it depends on your local conditions. Different soil types in different areas will change things a lot.

Im in the process of cutting up an old concrete drive here - was laid in the early 70s. Its a 2" concrete skin over earth - no hardcore, no mesh. It has some minor fractures, but i couldnt believe it was so thin when i started cutting it!


This is in Devon, but i have some experience from Essex, where the soil is clay, which moves about a lot more - you would not see 2" last a couple of years there, let alone 40 of them.


Have a look about to see how other things are constructed in your area, and you will get an idea of what lasts and what does not where you are.

 

[BrokenBiker]

its going on a dense mud bank, no clay there. At the moment they are parking on the mud and even in the bad rain there aren't any discernable areas that have sunk. I was thinking along the lines of about 4 inches which is what my father had on his drive about 3/4 mile away, similar soil underneath, no reinforcement or hard ore underneath.

i was thinking of putting hard core down for this though as its on a slope so i thought that might help.

 

[cumbriasteve]

It's one of those jobs I would only be wanting to do once and certainly not want to see it breaking up within a year or so.

Without seeing the terrain/sub soil/area drainage etc etc I would say a minimum 4" on well compacted hardcore with mesh reinforcement and if I had a few £££££'s going spare I would prefer 6"

 

[tlovatt]

Oh and it would have to be re-inforced ie mesh

You can use fibrecrete instead (polymer fibres as steel tends to show surface rust) much quicker to lay and stronger.

 

[tlovatt]

its going on a dense mud bank, no clay there. At the moment they are parking on the mud and even in the bad rain there aren't any discernable areas that have sunk. I was thinking along the lines of about 4 inches which is what my father had on his drive about 3/4 mile away, similar soil underneath, no reinforcement or hard ore underneath.

i was thinking of putting hard core down for this though as its on a slope so i thought that might help.

If the ground underneath is solid you can get away with a couple of inches, but you will only be able to get general advice unless the soil is tested and a proper engineer involved. For site roads it is quite normal to use 4" of Type 1 followed by 6" of concrete single mesh. If it is on a steep slop then you need to consider the possibility for the slab to migrate downwards or the risk of washing out the fines from the sub base. It also depends how worried you are about a few cracks in the slab after a couple of years.

I personally have laid a 3" C30 fibrecrete slab directly over compacted earth without a problem or any cracks

 

[dan.taylor.1]

Our farm yards are only 4-5" with mesh and haven't cracked with 25+ years of abuse from heavy tractors etc.

If your prep is good, compacted soil then hardcore that's compacted then the concrete you shouldn't get any problems with 4" with fibre or mesh, I'd advise some form of binder like mesh as the contact presure isn't going to be even as the tyres will be Sat on the same 6-8" band most of the time so it'll want to crack near there, especially on the verge side.

Dan

 

[BrokenBiker]

right ive just been out to view the ground. Its not as big as they said over the phone. There is to be a 3.3X2M slab laid at the top of the hill where the ground is level, then 2 paths both 7.6X0.4M leading down to the road to drive up.

ive quoted them for 400mm deep 4" and they are happy with the price. The ground is really hard, had a quick go with a pick axe and its not easy to break up so it should be ok. At the bottom of the hill the paths will sit level to the pavement so that should stop anything sliding.

 

[God mode restorations]

i been a civil engineer for 22 years....on ground work construction...i would put a six inch slab with with mesh....as for the sub base..it depends on the condition..but a good 100mm of crush concrete or road plainings should be good....and dont forget to polythene the base before the concrete pour....also i would hire a poker that really makes a difference to the strength and finish.....