Patio drainage

[Graham Jones]

Hello,

Imagine a patio surrounded by a retaining wall, house and garden are at two different levels. So patio will be against the house and retaining wall will be needed as currently there is a slope down to the grass. Next to house is an existing rainwater trapped gully.

My idea is to slope the patio towards this gully, so all rainwater will drain away properly, as patio will be surrounded by a retaining wall some drainage is definitely needed.

But the thought of sloping the patio towards the house seems counter- intuitive.

But will it cause any problems?

Thanks,

Graham

[Paul - xxx]

The last house we bought had a similar issue, garden sloping towards the house, 2' drop onto patio which sloped towards and connected to the house with a small drainage channel at the base of the house wall. There were two steps up to get into the house. The dpc on that wall was about 10" or so above the patio level and we had no problems whatsoever, except for 'the usual' .. leaves/debris blocking the channel and subsequent drain .. ;)

I suggest checking where the dpc for the house wall is and if there's any chance of water on the patio breaching it then it might be better looking for another solution.

[Tim Lamb]

In message , Graham Jones writes

I don't see why. We have a tarmac front yard which drains to a 6" gulley and then passes under the house. Obviously blockage of the grid or pipe and a deluge will eventually flood the house.

You may be able to arrange your patio slope such that ponding will overflow elsewhere before things get serious:-)

regards

[Andrew Mawson]

retaining

counter-

Run a length of ACCO surface channel drain on the lower edges and on into your trapped gully, that way heavy downpours are coped with easily.

AWEM (who has laid more ACCO drain this year than he cares to remember!!!)

[David P]

So why not take feed from the gully to a new drain point furthest from the house and put a new/extra gully in there? That way if it ponds it is away from the house.

You may even be inclined to put weep holes in the retaining wall so it can discharge onto the grass.

Or have I misunderstood the layout?