Damp caused by high ground level on neighbour's side

[cowrice]

I'm going to buy a 1970s detached house. It's built on a slope - upward from the driveway and downward from neighbour's house. There is damp in a wall on the ground floor, opposite to the neighbour's concrete steps to his garden.

The surveyor suggested that I can remove the damaged plaster and replace with waterproof renovation render, or clean up the breached cavity wall (if it's indeed breached after confirming with a borescope).

I'd prefer the latter option but it's expensive.

Does anyone have experience of this situation?

I've posted here about some other problems with the house too, and I haven't made up my mind whether I should go ahead with the purchase.

Possibly disturbed asbestos in the house I want to buy http://www.mumsnet.com/Talk/property/5058415-possibly-disturbed-asbestos-in-the-house-i-want-to-buy

I’m the op

The house I'm buying is on the left hand side. The damp is in the extended part of the house, where the ground level next to it is 500mm above the damp proof course.

imgur.com/a/7se35YO

I would skip this one if I were you. It sounds like a world of pain.

How old is the extension? The cavity is likely filled with rockwool, which will be sodden and require removing.
You’d have to talk to a damp specialist. Maybe airbricks could help it dry out.
However the physical issue remains, the ground level being higher than the dpc. That can also be solved by a bit of minor engineering work next door. Dig it out, install either a membrane then back fill with aggregate (stones) then reinstate everything. Or build them a retaining wall so there is an air gap. Also depends on the amount of space there and drainage what can be done. And a neighbor who is amicable to having a weeks worth of (minor) disruption.
It’s a dick move by the neighbor ( or whoever did it ) breaching your dpc.

I’d say unless this house is an amazing bargain in the perfect location that ticks all your boxes, I wouldn’t buy it.

It’s possible that the neighbors extension was built after ‘yours’ and they built that part up at that time, causing the issues. Looks like they have a door step on the side, but difficult to tell.
In any case, do you want to get into this with the prospective neighbor? Why hasn’t the current owner or their insurance company taken the matter up already?

The extension was built in 1970s. I've paid for a damp survey and the damp surveyor told me the solution is chemical damp proof course. However, the surveyor who carried out the structural survey advised that there is no need to inject chemical dpc.

The seller disclosed that there is cavity wall insulation made of urea formaldehyde foam, so I'm quite puzzled about cleaning up the cavity and consulted the surveyor again. The surveyor advised that it is very rare to have this type of insulation, and that the material is carcinogenic and needs to be removed. I can't imagine how to remove the insulation inside all the cavity walls in a house. That'd be huge work.

Even if you have damp proof render it will fail and require replacement. That won't ever not be an issue without significant work. Not sure why you would pursue this to be honest.

Walk away from this- it sounds an expensive nightmare!

I've paid for a damp survey and the damp surveyor told me the solution is chemical damp proof course.
Does the surveyor by any chance also sell chemical damp proof courses?

Yes they are the one selling the chemical dpc. I chose them because the structural surveyor recommended them, but I found out later that I'm wrong. I shouldn't have chose someone who sells dpc to carry out e survey. I'm a naive ftb.

The surveyor did mention that this approach is temporary, but he thought the damage to the plaster over the time of 50 years is considered to be relatively slight.

I feel so sorry for the seller. She is an old lady and a widow.

I should have done so once I realised the damp is caused by high ground level. Now I have to pay the solicitor's fee and the seller has to pay hers too.
I thought the problem was not serious, until I came across the photo I attached in my comment above. I haven't looked at the property in that angle as it was the neighbour's garden.

Your only other options are to get the seller to either drop the price by an appropriate amount, or to fix it to the satisfaction of your surveyor.

The doorstep is at the front of the neighbour's house. The steps are used for access to the garden only.

In the picture, there appears to be a step by the bin bag. Is there a door there?
In any case, a dpc is to stop damp rising above that level. Your issue is part of the whole wall is below ground level, so a dpc will do nothing to help.
Getting the foam out is not difficult, but won’t solve the damp problem.
You need access to the neighbors property to see what’s going on. The vendor must be friends with them? The issue needs to be resolved from the outside of the extension, which means from the neighbors property.

I think the problem is even more complicated given that access to the house's external wall needs neighbour's consent.

Unless this is your dream house, I'd walk away. Your sympathy for the widowed vendor is admirable, but why buy trouble? You're already worried about the asbestos, with damp problems on top, I'd give this one a miss.
It's unfortunate that you have already incurred costs, but you don't want to be throwing good money after bad. And these problems could need a lot of money throwing at them. And that's assuming you can find good reliable tradesmen to do the work anyway.

I would be very apprehensive buying it and expecting it to be solved with damp proof injections. I also have a damp area in my house that is so far not resolved. This is after already having a chemical damp proof course as suggested by the surveyor when we bought the house. It did not work! After investigations, because I didn't initially know anything about this and the surveyor had said nothing, I think the damp proof course has been breached by high ground level all along that side.