Soakway for carport

[oldgirl]

Hello everyone. I am coming after quite a long time.
Would like some advice on how to provide drainage for 20m2 proposed car port.
I want to replace my existing concrete drive with paving bricks.the new regulations requires installation of a drainage channel and a soakaway for the surface water runoff from the drive which is 20m2.The soil is clay. The soakway is supposed to be 5m away from the house. This I think is just not possible. I've a depth of I've just 3.8m. The width of my semi detached house is approximately 5m. The semi on the other side with whom I share a common area leading to the back garden, has paving block drive with runoff into the public sewer as it was done some 25+years ago.
So I don't know where to put a soakway. Lots of houses on my street hv had new drives done and I can see a channel. All these houses hv similar depth ie. Just under 4m. The front area slopes towards the road.
The water from the roof drains into an existing drain.
Also what size of soakway do I need. Council Web site says 1m3. This seems too much. Also am worried about whether water will drain away as soil is clay. Also bit worried as car will drive over this drain so should it be then covered by a concrete slab.

 

[Hugh Jaleak]

Speak to Building Control at the Council, there is a hierarchy for drainage in these situations. If a soakaway isn't practical then they may allow connection to a surface water drain, and if that isn't possible, then a combined sewer can be considered. Alternatively, don't say anything, (you're replacing an existing paved area, not creating a new one), and just connect the drainage into the existing drain that takes the water from the roof, assuming this connects to the sewer.

 

[Doggit]

Alternatively, you could use permeable paving, but if you're on a clay soil, then this could give as many problems as a soakaway in clay soil. And if you poke a stick in the ends of the other drains down the road, I suspect you'll find most of them don't have a soakaway at the end of them either.

As the current drainage regs are trying to get more water back into the ground, BC may not allow you to direct back into the surface drains, as that's pretty much having paving that takes the water out on to the road.

Soakaways used to be great big holes in the ground filled with bricks, so needed to be 5M away from buildings, but todays modular construction systems are a lot more compact, and may well be allowed under the paving itself, but you'd need to dig a hole from the soakaway down below the clay to allow proper drainage

Checkout http://www.pavingexpert.com/drain08.html for a few ideas

 

[oldgirl]

Thank you Hugh and Doggit. I'm thinking of I put in one blue soakway crate, would it create any long term problems to the house considering that it is always raining in this country and water may not hv sufficient time to drain.

 

[Hugh Jaleak]

Problem will be with clay soil, that the water simply doesn't soak away, and once the soakaway becomes waterlogged, it is no longer fit for purpose and the area will flood anyway. Whilst surface water drainage has to be controlled to avoid flash flooding when watercourses can become overloaded in times of heavy rain, this also has to be balanced with existing needs. Adding a small area to be drained onto an existing sewer isn't in itself going to be a major issue, BCO's are pretty adept at making the right call for individual circumstances.

 

[oldgirl]

Thank you Hugh. I really do feel that putting in a soakway will not be good in the long run.
I tried to contact BCO today unsuccessfully. Will try again 2moro. I'm sure common sense will prevail. I've not found our council unreasonable to date.
Thank you. Will let u know how this concludes.
Shree

 

[Hugh Jaleak]

If they insist on a soakaway, tell them you'll do a percolation test. This will determine how much water the ground will accept, and is the acid test to prove if a soakaway will work or not.

 

[oldgirl]

Thank you for your help. I got thru to the BCO and they agree that I can connect to the drain that takes the roof water. He agreed that soakway not a good idea under the circumstances.
I also remember now that two houses hv put in a new front drive(Permeable? ) and they both slope towards the road and neither of them hv channels or any visible means of drainage!
BCO said that as my drive slopes towards the road I must connect to the existing drain. So b it.
Thank you once again for your help.