Channel drain, damp, patio too high

[Mr Chibs]

Hi all

Had a spot of damp get to the point where I need to do something about it.

In a nutshell, stone paving has been laid onto concrete patio, and at end of the house it's about 30mm higher than the dpc, due to slope.
It's an old house, and the dpc looks like slate.
In a bid to sort it without ripping up the whole patio, I've chopped a trench around 150mm from the wall, roughly 150mm deep, until I hit soil.

I'm therefore thinking of laying some channel drainage.

Just wondered:

A. should I put any membrane next to the wall before the channel drainage goes in?
B. is there a better way than the channel drainage?


I'll take some pics once it's stopped bloody raining, but have this, so you get the idea.

 

[John D v2.0]

We have the same, although the channel was full of mud and stones and water was penetrating to under the floor void. I was planning to do exactly what you drew to collect the water, so I'd be interested in any responses.
My only concern is water running down the wall and behind the drain, so I was thinking of either chasing some kind of drip bead into the wall or some flashing, or just putting it hard against the wall and using frame sealant or some other bodge. Maybe in your case that won't cause a problem anyway.

 

[Mr Chibs]

Think I'll start with a bead of sealant.

I was thinking of some wide DPC under the channel and up the wall, but think that may not be necessary.

Will keep you updated.

 

[Ian H]

I would stand the channel off the wall slightly, just so you can fill in behind it with concrete or mortar.

 

[Mr Chibs]

Would you bother with the dpc?

Here's an image of current state

 

[Ian H]

I wouldn't but others might.