Issues installing ACO drain level

[Circuital]

Please see the video attached - it explains everything quickly. This is a 1936 house, with cavity walls. The walls contain rockwool type insulation and the builder thinks the bricks need a coat of water repellent. I also intend to clear the cavity at some stage. However, this post relates to the fact that the level of the slabs/concrete is higher than the DPC around the side of the house.

Hello, my builder and I have been digging a trench around the sides of my house, as it appears the paving/concrete is higher than the DPC in places. This is causing damp issues on the inside. However things have proved to be difficult and I would be grateful for your advice.

The idea was to put ACO channels in and direct the water to the existing drains.

SIDE OF HOUSE INFO
As you can see from the video, since the house is on a slant, one end of the ACO would be flush with the level of the paving whilst in the far corner of the house, putting the ACO in flush would bring it above the level of the DPC. I can't dig any deeper because the builder seems to think that we're hitting the footings of the house.

BACK OF HOUSE INFO
I can't see the DPC but assuming it is at the same level as at the side of the house, it is all under the finished concrete level. Further issues include the presence of a soil pipe and lead pipe.

Again, thanks for your time!

 

[cdbe]

Try to avoid the pipes by falling it all the other way round the corner. There's a slight risk, but the new drainage should mean there's very little standing water if any section has to be above dpc - and the outer skin is designed to cope with a bit of water penetration above dpc.

 

[Circuital]

Thanks for your suggestion, connecting it to a corner piece, was a solution we had discussed, so that's reassuring.

What would you recommend I do directly above the pipework and the section to the left of the drain (see circled pic) please? I haven't dug out that part yet but it's definitely the highest point of the path, so way higher than the DPC.

Thanks again.

 

[Circuital]

Also, would anyone recommended lining the channel with anything before fixing it in with sharp sand and cement please? Perhaps bitumen or something like that? Is it worth coating the lower courses of bricks with such a substance too?