Hard standing drainage regulations

[Captain Nemesis]

if the whole area is say, on 43 ft deep London Clay, no SUDS system will be perfect unless you drill 45 ft bore holes through to the chalk aquifer.

Are there any (free, online) geological maps available which show what the ground is made of? My council (Hillingdon) wants a soakaway to take the water from an extension roof but Im not sure it would work.

 

[Nakajo]

There's no map of sufficient detail. This is why we do soil investigations - and even those can be misleading if you happen to be a little unlucky with your bore hole location.

 

[Keithmac]

What's best permeable drive solution?.

We have gravel at moment but was mulling over having ours done.

 

[Captain Nemesis]

I quite like the look of resin bound gravel. Paving expert site has useful info. If you want to get fancy you can have decorative designs done or even use glow-in-the-dark stones in the mix

 

[frutbunn]

Are there any (free, online) geological maps available which show what the ground is made of? My council (Hillingdon) wants a soakaway to take the water from an extension roof but Im not sure it would work.

The British Geological Survey have maps on line and a data base of test holes, bore holes etc
https://mapapps.bgs.ac.uk/geologyofbritain/home.html
This gives a general overview.

 

[Captain Nemesis]

 

[fairplay]

Well in the event I got a permeable resin drive done in a natural gravel colour. It is now one year old and looks fantastic. It has been a worry because the day they started the groundwork the drought broke and we had three days of rain, one record breaking day of 100mm! This left a clay muddy mess with puddles. They still proceeded with the type 2 and type 1 coarse. After compression - still looked a bit soggy to me they laid the porous concrete. I suppose a week or two had passed before they laid the resin which they got done about ten minutes before another downpour. It didn't seem to have affected it though. I was fully expecting it to dip in places but so far all is good and I couldn't be more pleased. The drainage is unbelievable and it is bone dry ten minutes after massive downpours that flood next door's block paving!
Which brings me to that. With no planning permission they have paved almost the entire back garden of 80ft by 30 ft with just a small patch of lawn in the middle. I expect that to be astro turf at some point! Then erected a summer house which is the full 30ft width at the end of the garden.
Frankly the planning authorities couldn't care less round here and I don't know why I worried about it.

 

[Keithmac]

All the resin drives down my street have a drainage channel.

Your permeable resin drive sounds ideal, I'll have to look into it.

 

[^woody^]

Resin bound (resin mixed with the stone) is permeable, whilst resin bonded (stone spread on a layer of resin and cheaper) is impermeable.

 

[fairplay]

Indeed. The majority of drainage channels across the front of drives are a scam by driveway contractors (or they don't understand or don't want to understand) the SUDS drainage regs. This is to fool the local planners into thinking they have a proper drainage system and the Authorities either turn a blind eye (because would you want to be the person to knock on the door of that many homeowners and tell them they have to dig their new drive up!). If you have a porous driveway (resin bound on a permeable sub-base) why would you put a channel in? So you basically have a sump beneath your drive from which the water can drain slowly into the ground.
So most people wing it and get away with it. But the reality is whilst the media are currently panning the Water Companies for pumping raw sewage into our estuaries and the sea it is because they can't treat the shear volume of water which we are causing via this run-off and it is the local planning authorities letting it happen in breach of the regs who are the problem here, not the Water Companies (although of course they could alleviate the system by spending more on bigger treatment plants but you know who would end up paying for that and it won't be the shareholders!)