How to defend drainage channel from soil (fix cowboy job!)

[Wetbean]

Hi - looking for some advice from you esteemed experts

Builders recently removed some patio slabs from our garden. We plan to plant a small tree and some plants, so the slabs have been replaced with soil. The removed slabs used to hide a small drainage channel. They were in a rush to complete the job and simply placed two drain covers between the soil and the remaining slabs.

When it's rainy or windy, the soil falls through the drain covers and clogs up the drainage channel.

I think I need to create a barrier that properly isolates the soil from the drainage channel but would like some advice, especially:
1. Is introducing a barrier the only solution?
2. If it is, how should I go about creating the barrier? If there is another solution, how do I go about implementing it?

Pictures below:

1. Without annotations

2. With annotations

3. Alternative view

 

[SFK]

Your old paving slabs, cut in half or into three lengths. Buried upright next. To drain at height same as surrounding paving, or slightly higher than soil, or much higher than soil.

SFK.

 

[JohnD]

Where is the DPC?

 

[Wetbean]

Thanks @SFK

1. would it be feasible to use adhesive to glue the upright, 3rd cut slabs?
2. I don't have tools beyond chisel and hammer. Is it possible to get a clean cut of a slab that will adhere to the ground, using just a chisel and hammer?

 

[Mr Chibs]

Have you got access to angle grinder, if so you can cut slabs with that, using a diamond disc... £5+

What about using roof slate bits if you have no grinder?

Or concrete path edging.

 

[Odds]

I'd replace the slabs removed beside the house and if you still want to plant a small tree then perhaps you can take out a few slabs from the next row along, away from the house.. It'll be easier to keep branches off the walls, bearing in mind tree roots can travel far in search of water. The further away from the wall, the better.

 

[JohnD]

The position of the DPC is very important when you have water next to a house. Paving and flowerbeds often cause trouble. Can you see where it is?

 

[Wetbean]

@JohnD How do I determine the position of the DPC?

 

[JohnD]

Look for it.

It is typically a thin black horizontal line in a slightly thicker horizontal mortar joint, about 9 inches above where ground level used to be when the house was built. Unless on an extreme slope, it is pretty sure to be at the same height all round the house. It may be easier to see under or beside a doorway.

If you have an unplastered wall, for example in an integral garage or porch, it may be easy to see.