Permeable or standard block paving?

[Vijay]

Is it just personal choice on what to use or would a clay sub layer determine things?

[Jeremy Harris]

It depends on whether you're required to comply with SuDS or not ( http://www.susdrain.org/ ).  If you are (and we were, it's not in our planning permission but is in the planning policy that applies to all new developments) then you need to ensure that water cannot run off from any hard landscaping (drives, paths etc) and leave your boundaries.  If you have a non-permeable subsoil, like clay, then you can either:

 

 - Make the area under the paving permeable, by digging out to a fair depth, fitting drainage crates for surge storage, arrange for that collected water to drain away somehow and use permeable base to lay permeable pavers over this, or,

 

- Fit drains around the edges/bottom of the hard surface to collect any run off and either feed it to a suitable drain  or collect it in some form of surge storage system that can slowly drain somewhere.

 

We installed twenty heavy duty Aquacell crates, wrapped in terram, just above the water table and about a metre under our drive.  These drain into a thin layer of soil above the clay that has a pretty slow drainage rate (long percolation time), but this is OK as the surge storage capacity we have is about 3,920 litres, so we can take the maximum storm rainfall OK without water running off into the lane.

 

The alternative is to use a combined sewer, that will take surface water as well as foul drainage, but I'm pretty sure that most water companies are now either restricting this, or refusing to allow it altogether, because of the capacity problems it creates for them.

 

Whether you opt to use permeable pavers or non-permeable with edge drainage really comes down to the topography.  We have a drive that slopes down to the lane at the entrance, and a linear interceptor drain across the entrance wouldn't have been able to take the flow under the max rainfall from the table in building regs, so we pretty much had to use permeable pavers with drainage underneath.  Permeable pavers aren't the only solution to complying with SuDS, though, and there are some other options on the Susdrain website.

[Vijay]

I couldn't find anything on the council website so I've emailed them to see if they have any policies on driveways. 

 

One of my planning conditions says "Prior to first occupation of the development hereby permitted a positive means of drainage shall be installed to ensure that surface water from vehicular access or private land does not discharge on the highway". The end of my drive is about 160m away from the highway down a private access road (for 4 properties), so I don't see how that condition can apply to me.

 

Reading on here http://www.pavingexpert.com/drain14.htm gives a few ways of dealing with drainage at the end of a drive

[Onoff]

Don't know if this helps:

 

https://www.planningportal.co.uk/info/200130/common_projects/45/paving_your_front_garden

 

&

 

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/7728/pavingfrontgardens.pdf&ved=0ahUKEwiQ1Yiv59LSAhWCtRQKHV2JCyIQFgg9MAE&usg=AFQjCNGNz_cqYzJdzCjaCvCutHTua44jfQ