New slabbed driveway and gravel path

[iaingray741]

Hi all,

Just looking for some pointers on my driveway. I'm adding two rows of slabs to get my car in on and then was planning for gravel all around.

I'm planning to dig out 200mm all over, then fill with the following -
- 120mm type 1 sub base.
- 30mm sharp sand (under the gravel) or 30mm dry sharp sand and cement mix (under the slabs).
- 50mm gravel or 50mm concrete slabs on the top.

I'm just looking for a sanity check as i've never done this before! Does that seem correct?

Should I still have sand between the sub base and gravel, or just a thicker layer of gravel?
What ratio sand and cement should i use under the slabs? Should it be a dry mix?

I'll get a compactor for the sub base, should i use it on the sharp sand too?

Any other advice would be appreciated!

Thanks,
Iain

 

[r896neo]

You need to spec up your plans.

What slabs are you using? They should be at least 40mm thick and need to be firmly laid and stuck to the bedding. Slabs laid to a free edge like gravel will want to flip up when the car hits their edge so they need to be over engineered compared to a fully slabbed area were 50mm bedding mortar would do fine.

The sub base should be a minimum of 150mm then I would recommend the slabs laid on 60-75mm of fine concrete 3 parts 10mm stone 2 parts grit sand 1 part cement. Add 150ml of sbr to each mixer full. The flags need a generous haunch at the sides.

You should then fill around them with more sub base and finish with 50mm depth of gravel. No sand or anything under gravel, just compacted hardcore then the gravel.

 

[iaingray741]

I have 900x600x50mm concrete paving slabs.

Great thanks for the suggestions. I wasn't familiar with SBR, but it sounds like it'll be a good idea from what I read.

 

[r896neo]

If your going to use slabs on a driveway pressed 50mm flags like yours are about the safest bet.

Use a pretty wet mix and use some sbr as mentioned, if you buying some anyway then slather on plenty on the back of the flag too for maximum adhesion.

Beware sbr stains or splashes must be washed off immediately. levaing them for even 30 seconds will leave a blueish stain which will take months to weather off.