Replace tarmac with block paving

[adiestoute]

Hi
Is it feasible to take up the tarmac which is 75mm deep, leave the sub base as is and lay 50mm blocks on 25mm of stone dust?
The finished height has to remain the same.

Many thanks

[mickg]

if the sub base under the tarmac is a depth of 150mm then yes this is fine

[lemoncurd1702]

Thing to do is look at the driveway as it is, are there any odvious depressions, potholes etc. If not then it should be good to go even if not quite 150mm.
A lot depends on how long the drive has been down i.e. if it's been there 10 years or so with no depressions then great.

I'd aim for about 35mm of bedding and grit sand rather than dust. You will find the blocks don't bed into dust very well, particularly at 25mm.

[adiestoute]

Thanks for the replies. That will save me a lot of work