Driveway Soakway

[mike2016]

Hi,

 

I've looking at the design of a driveway in a new build. The size is 6 meters deep from the street to the front of the house and 8-9 meters wide. There is a slight slope down from the street level to the front of the house. I'm planning on diverting the house gutter downpipes to an underground rainwater tank at the rear of the house. There are just two things I need advice on if someone can help me:

• How to ensure run off from washing a car, or any fuel/oil leak doesn't go down the downpipe drain mentioned earlier?
• Use of permeable paving - is the driveway too close to the house so using this would create a risk to the foundations?

I'm guessing I need a separate channel (possibly where I've marked in RED) to capture any run off from the driveway and divert that directly into the storm drain, otherwise I'm risking mixing fuel/oil/detergents getting into the rainwater storage tanks.

I'm keen on permeable paving but from what I've read they don't recommend it close to a house. I'm doubtful if 1.2 meters is sufficient (The wheelchair access area around the two spaces below). I'd need to understand where the water goes once it soaks through the permeable driveway aggregate so it's channeled to the storm drain correctly. 

 

I can always do a concrete driveway and build a channel into it to capture runoff but wonder about other options.....? 

 

Thanks! 

[Ferdinand]

On the roof connection, I think you just plumb it as continuous drainpipe that runs straight into an underground pipe to the tank. Rather than into a ground gutter.

 

I have such pipes on my house but I have never built one.

 

Ferdinand

 

Edited February 13, 2017 by Ferdinand

[Jeremy Harris]

We laid permeable pavers, on to the right sub-base (type 3, not type 1) and under the sub-base we fitted Aquacell crates wrapped in terram to form the surge capacity/soakaway underneath the drive.  As these were well below the house foundation level we also ran all the rain water drainage to them.  It seems to work well, although the sharp grit used with permeable pavers seems to need topping up, by brushing more into the gaps, every year or so, probably because the gaps are wider with permeable pavers.

[mike2016]

Thanks for the news on the gutters, makes sense when you say it, just different from normal houses I'm used to! 

 

I've seen pictures of those Aquacell crates used in car parks etc, didn't know they were used in Domestic installations! Is this all the way around the house, or just the driveway? Surprised they are below the level of your foundations, but then I've not seen a build close up yet......Cheers!

 

 

[Jeremy Harris]

We put the crates in to comply with the SuDS regs, see here for more info: http://www.susdrain.org/

 

They are only under the drive, the rainwater from the house gutters etc is pipe down to them.

 

We also had to make sure none of the run off from rainwater entered the stream on the other side of the lane, which is a joke given the way the lane itself turns into a stream in heavy rain!

Edited February 13, 2017 by JSHarris

[Gone West]

Our BCO and the Highways Dept. allowed us to discharge roof drainage directly onto the lane because of the very variable water table level. There's not much point in SuDs down here, the lane is the drain.

[mike2016]

The Rain in the Lane, 

Is caused mainly by the Drain?

 

Sorry.....probably low on coffee here...!!

[joe90]

I had a similar conversation with my BCO when he asked for a soak away for the garage I said you mean a pond and showed him the solid yellow clay we have just under the topsoil, I simply piped the French drain out to a ditch next to the road. Nothing was ever mentioned again and I got my completion certificate. The house and treatment plant are another matter which I am not looking forward to dealing with!!!

[Jeremy Harris]

We did much the same around the edge of our plot, alongside the lane that turns into a stream in heavy rain.  We had to dig a deep trench all along the two lane-facing sides, to relocate the electricity supply cables and telephone cables that used to run overhead.  Instead of filling those trenches with the clay soil we'd dug out, we filled them almost completely with gravel, with just a thin layer of soil on top to hide it.  It works pretty well, but we still have an area in the lane, right at the end of our drive, that turns into a shallow lake when it rains.  I wanted to just re-tarmac that section of lane to remove the camber where our drive now joins it, so removing the dip, but the highways people wouldn't have it.  Instead, we left the end of our drive a bit higher, so when they next resurface the lane, with a bit of luck, they may just correct the levels.

[Onoff]

Makes me wonder when I come to pave my driveway whether I'll need to faff around with a soakaway as the lane at the bottom of the drive was and still is a seasonal water course:

 

 

[Temp]

Our down pipes go into 110mm drainage pipe with a rubber gaiter to stop any debris getting in.

 

How about "reinforced grass" for the car hardstanding..

 

https://www.google.co.uk/search?q=reinforced+grass&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiZ6ufttJfSAhWCCMAKHbL2AB4Q_AUICSgC&biw=1288&bih=745#imgrc=w46yPyEId0Em-M

[mike2016]

Nice alternative, I'm taking a break from grass for a while I think - fed up cutting it all the time. Cheers though and thanks for the info on the rubber gaiter. 

[Oz07]

I think the point of permeable paving is that unless it's heavy rain the paving shouldn't be directing the run off anywhere. Therefore the rain should fall where it has always fallen and shouldn't pose any extra risk to your foundations. Obviously it makes sense to put a channel in for surge capacity though.