Driveway advice

[bigray1]

Evening all

I am looking to extend my current driveway. At present I have a 25 x 17ft part of my front garden which is half grass and the other half concrete. I am looking to convert the whole area to a large driveway.

I know you are supposed to have around 100-150mm type 1 then around 60mm of sand before laying my slabs/blocks. However, my sub base soil/earth is full of stones/pebbles and as a result is very very hard. I have parked my car on the grass for the last 2 weeks and it hasnt even made a mark (and we have had some torrential rain).

My question is, do you think I can simply remove some soil and lay the sand straight down without any type 1????

Many thanks

 

[HERTS P&D]

No.

Andy

 

[pred]

And no to 60mm of sand also!

 

[bigray1]

Why no to 60mm of sand mate? Paving expert site recommends 55-65mm.

I have just removed the turf and began removing the soil, however I can only physically dig down a couple of inches before the ground becomes too hard and rocky. I can't even get through it with a large pick axe. Will I need to hire a mini digger now to excavate it???

 

[^woody^]

The problem with soils are that they are unstable and can easily move/compress with water, frost and vehicle weight.

If the ground is as hard as you suggest and is free draining, then it may be OK. But its a risk.

If you had say 100mm of compacted sand then it may be less of a risk

 

[pred]

I would go for 100mm compacted half to dust then using two guide rails as discussed a few days ago put stone dust down, level it off, throw your block pavers down and finish off using a whacker plate with rubber mat.

This is after you have gone round the boarder putting concrete edging at the pavement and setting the boarder blocks on concrete.

 

[bigray1]

Sorry Pred, how do you mean 100mm compacted half to dust???

 

[r896neo]

I guess Pred means 100mm of 1/2'' to dust hardcore. Stone dust is a terrible thing to lay paving on as it holds water badly.

I also doubt it says 60mm bedding for block paving on the paving expert site.

You want 25-40mm of grit sand.

If you are really convinced of the sub-grade and its for your own home then go nuts you could always remove and previous surface and add some hardcore just be sure you have enough clearance blow DPC.

By the time you lay 30mm of sand and a 60mm or 80mm block your going to have to dig at least 4 inches out anyway.

 

[limerockconstruction]

He's talking about half inch to dust....slang terminology for ballast/chipping etc. Largest size of stone is 1/2" all the way down to dust.....simples!

 

[pred]

If you got a decent base 1" of dust is plenty, if you have not got a decent base you got more work ahead of you.

If you don't do it properly the first time and take short cuts you are going to pay out more in the long run.

 

[r896neo]

Don't lay paving on Dust!!

 

[bigray1]

Confused now gents. I have a digger turning up tomorrow to excavate the ground. A firm that a doing a drive at the end if my culdesac said I only need to go down 6inches, add about 3 1/2 inches of sub base then 1/2 inch of sand.

They also said type 1 mot is not necessary. They are using something that is black in colour and he said goes very very hard when compacted. Shalling or something???? They also said it was a lot cheaper

 

[noseall]

Confused now gents.

Dig out fertile soil or soft absorbent stuff.

Lay compactable granular material and compact it.

Lay screed sand (aka, sharp sand, grit sand, concrete sand) compact this then lay paviors onto sand that has been screeded to falls.

Compact the paviors.

 

[r896neo]

They are using road planings/ scalpings which are a waste product from re-surfacing roads. Their suitability for a sub-base in questionable and usually its the fact that they are so cheap that convinces people they are ok.

As far as i know there has been a few reports into it mainly saying they are a problem and one or two saying they are fine.

Seriously though how much MOT would you need? 5 tons or something costing maybe 130 quid? Why spend all the money on blocks and do all that work and risk them being ok for the sake of saving 50 quid?

try laying blocks on 1/2 of sand and you'll soon see the stupidity of that suggestion. Your sub-base will have to be perfectly flat.

Sub-base wise it's up to you it's your house but driveways are normally layed on a minimum of 150mm compacted type 1

Then 25-40mm of grit sand

This is the current british standard recomendations for flexible block paving

 

[^woody^]

They're called scalpings, and will be fine to use.

It is not so much the depth of the sub base, but the condition of the ground beneath. Typically, 150 stone and 50 sand is recommended as this equates to the depth of top soil which needs to come off when the depth of the blocks is taken into account.

You do need 50mm of sand to bed the blocks, not 12mm. If the ground is as hard as you say, then 75mm of stone may do.