Two linear drains or one or ...?

[phander]

I have a patio of approx size 6m x 4m.
There is a linear drain (working and properly installed) against the sliding doors at the back of the house.

The other side of the patio ends in a concrete retaining wall of height about 50cm.

The next step is laying a patio (which should slope away from the house, I realise). So I'm wondering whether I should install a second linear drain at the base of the retaining wall? Or is this overkill?
I already have a gulley in one corner of the patio (near the retaining wall).

Hope someone can help. Thanks!

[seanandruby]

Any photo's?
look here

and here
Is there weep holes on t'other side of retainer?

[phander]

Here is one.

Ignore the mess but on th e left you can see the edge of the sliding doors and a linear brickslot drain.
I've got pipework set up for a gulley at the top right of the the picture.
The beighbours wall has a concrete fittong our side to support it. On the right you can see the concrete retaining wall.

I'm wondering about the need for a second linear drain running against this retaining wall.

[seanandruby]

That is some door recess.
Are there two linear channels side by side? Think you need to take those out, install a slot drain at the threshold. Think i'd put linear channels along the wall piped to a drain

[phander]

The door recess is because these are 3 very large sliding doors - that cross each other.
THere is only one linear drain at the threshold. It's an aco brickslot type.

When you say linear drain against the wall do you mean the side wall or the concrete retaining wall?

[seanandruby]

Where your fall is heading for aco's.

[phander]

Sorry I don't understand.

[Tony McC]

Sean means to ask to where will the linear drains outfalll? They slope from the door threshold to where?

You can't have too much drainage. You can waste money on having too much, but it won't do any harm as long as it's properly installed.

6x4m is a relatively small patio and a single slot drain at the door threshold would more than suffice, but if you want to over-engineer, then run one along the wall, possibly connecting to the threshold drain.

However, on such a relatively small project, there would be no harm at all in sloping the paving back towards the house (and that threshold drain), just to keep things simple.