The wrong driveway material?

[Post and beam]

When our house was first under construction a large amount of crushed rubble was poured to form a drive way, mainly to support the 35t Crane but also all the vehicles that visited.

It currently performs as a perfectly serviceable driveway.

But it fails the SUD's permeability test.

As far as i can see then only option is to have it removed ! and then to lay a compliant type 3 base.

 

Does this sound correct?

 

 

 

[Redbeard]

Yes, possibly. Permeable substrates leave lots of gaps and have few or no fines. What you describe sounds like 'MOT', which will have compressed, the fines filling in the gaps and leaving a very serviceable not-very-permeable surface. If it was what I think then it never could be permeable enough for a SUDS solution. But I may have misunderstood. Can you give us more detail, please?

[garrymartin]

No, it does not sound correct.

 

New drives in front gardens over 5m2 need to be permeable or discharge to a permeable area, but that is only to avoid the need for planning permission. So, two questions. What did your planning approval say about the drive surface (if anything), and does the surface water from it discharge to a permeable area, or can it be made to? It's all about flooding and reducing pressure on public drains, so if that is not applicable, it's unlikely you'll need to change anything.

 

[markc]

I have seen the permeability test “sorted” after a site used type 1. Contractor drilled holes and filled with clean graded stone/pebbles. … and no, it wasn’t me!

[Post and beam]

49 minutes ago, garrymartin said:

What did your planning approval say about the drive surface

Must be SUD's compliant.  Otherwise i would not give this a moments thought.

51 minutes ago, garrymartin said:

can it be made to?

This is not my area, i have no idea. The frontage of the property is 18 metres wide, most of which was covered with the previously mentioned rubble. I did wonder whether channels could be cut across it to bury french drains and take the water to the side where there is soil. Otherwise i am back to ' i have no idea'.

[Post and beam]

5 minutes ago, markc said:

drilled holes and filled with clean graded stone/pebbles

I suppose this very useful piece of 'theoretical' advice depends entirely on whether it is my choice where the test is filmed. no idea what kind of evidence is expected. But thank you.

[garrymartin]

If the runoff can be managed on-site naturally, then the surface does not have to be permeable to be SUDS compliant. There should be lots of options that don't require you to rip it up.

[Post and beam]

2 hours ago, garrymartin said:

lots of options

Possibly true, i just need to learn what & how this might be achieved.

[Mr Punter]

If it is rubble filled why not claim it is compliant (if asked) and see where you stand.  If you top it off with gravel or permeable block paving I can't see questions being raised.  I have had a SUDs condition and it was never checked.

[torre]

What if any surface layer will the drive have? If that will be impermeable anyway (e.g. traditional tarmac) then there's no point changing to a permeable sub base.

 

Can the drive be laid to a slight fall, such that run off is naturally towards a permeable area (soil) on your own property? Looks like 100m2 of drive needs 20m2 of permeable run off area. Otherwise you're into needing to construct some sort of drainage/soakaway.

 

I'd work out how much MOT type 3 you'd need as a replacement sub base to at least see where you are on cost and consider how that compares to any alternative approaches. @Mr Punter you're probably right and no-one may check, but if they do then costs to redo a finished drive later will be a lot higher than cost of redoing just the sub base now.

[Post and beam]

4 minutes ago, torre said:

What if any surface layer will the drive have?

It depends, is the only answer right now. If i can get away with grading it to fall towards soil then it will stay as it is. If it were not a planning condition to be SUD's compliant i would leave it as it is.

Worst case, if i have to dig up what is there today then all bets are off.

[FarmerN]

We did an expensive SUDS compliant block paving drive way, took a fair bit of time and care doing it.

Two years in and it's an awful lot less permeable than it was , guess is in 5 years it won’t be permeable at all.

Mud from car wheel arches and muddy boots from gardening and walking soon fills the permeable cracks, being in a rural area there is plenty of mud around..

Fortunately it doesn’t matter, to us.