Protecting a wall from neighbour’s plants/damp

[Adsibob]

Brand new extension wall, built on very deep foundations (about 1.8m to 2m deep) that our BCO insisted on. On top of the foundations we have about 3 courses of engineering brick, then facing brick. There are also two DPCs if I remember rightly, one directly above the engineering brick and the other a bit further up. 
After a lot of wrangling with my neighbour, we finally had a civil conversation about various things, and they have agreed to chop down various things affecting our light if I put up some trellis on this wall so that they can plant some plants to grow up the wall on the trellis. My builder thinks it should be fine as he has sealed the bricks and the wall is so well built he didn’t think there will be any issues. Is he right?

The wooden trellis won’t be fixed directly to the wall, it will be fixed to some plastic spacers which will isolate the trellis from the wall. But there will obviously be some fixings drilled into the wall. Neighbour is keen spacers are only 5cm deep so that the trellis is in the same position as the fence would have been to match the rest of the fence. 
Is there anything else I can do to prevent future problems, say in 15 to 25 years time?  Neighbour has agreed to keep plants to no higher than my wall, so that there are no issues with the plants affecting the roof. Obviously enforcing that might be tricky, but I do have fairly easy access to that roof from a bedroom window, so if he doesn’t comply with his promise I could in theory trim it myself.

[joe90]

I think it should be fine as long as he does not pile soil above you DPC. Nothing worse than falling out with neighbours.

[Conor]

Should be fine.

 

Only concern would be the soffit and fascia in 15 years time when the plants are enivitably left to their own devices.

 

Only suggestion I can think of would be to put up non woven weed membrane behind the trellis to stop any plants attaching themselves to the wall. 

 

Then again there are buildings 100s of years old covered in aggressive ivy that are just fine...

[Adsibob]

There is no soffit or fascia there, it's a contemporary style roof with the gutter concealed within the roof (on my side of the wall). Good idea re the weed membrane.

2 hours ago, joe90 said:

I think it should be fine as long as he does not pile soil above you DPC. Nothing worse than falling out with neighbours.

How do I design something to stop that? The soil line is currently well below the DPC, as all the engineering brick courses are above the soil line.

[joe90]

40 minutes ago, Adsibob said:

How do I design something to stop that?

You can’t but as you appear to be getting on with your neighbour just point it out.

[Adsibob]

3 hours ago, joe90 said:

appear to be getting on with your neighbour

this is probably overstating it slightly. We've just had the first civil conversation in years.

[joe90]

39 minutes ago, Adsibob said:

We've just had the first civil conversation in years.

Well that’s a start 🤷‍♂️