Strange scenario of a garden wall. Help please.

[JibT]

I have a wall that surrounds my small garden.

My neighbour, to the left, has what used to be a "lean-to" on the other side of said wall.

Over the years, the lean-to became a more solid structure with masonry walls at right-angles to the garden wall. It has gradually changed from being a garden shed through a "dry" storage area and onto becoming an outside laundry-room into ultimately being an extension of his/her kitchen.

The thing is, being a garden wall, it never had a DPM (Damp-Proof-Membrane) installed, when it was built.

To me, it's a garden wall. It just might be the best garden wall in the world. It does everything that a garden wall should do, from my perspective (being a wall in my garden).

But to my neighbour, it's no longer a garden wall. It's a structural wall which is possibly the worst structural wall in the world because of the damp he is suffering in his kitchen.

Maybe I shouldn't care (but, he's my neighbour so I do).

Is there any way we can economically insert a DPC (Damp-Proof-Course) into an existing single-course (Breeze-Block) wall?

Any help or advice would be sincerely appreciated, thank you.

Jib.

 

[RHGrenedier]

What length of wall is considered?
Don't forget that damp can travel horizontally as well as vertically. So any attempt at a damp course in the wall will need to consider proofing the wall vertically to the side of the end walls of your neighbour's extension.

I would also suggest rendering your side of the wall, at least.

If the wall is only single course, then there is a good chance that internal damp is condensation.

I would have thought, you need to think more holistically than mere dpc.

 

[JibT]

What length of wall is considered?
Don't forget that damp can travel horizontally as well as vertically. So any attempt at a damp course in the wall will need to consider proofing the wall vertically to the side of the end walls of your neighbour's extension.

I would also suggest rendering your side of the wall, at least.

If the wall is only single course, then there is a good chance that internal damp is condensation.

I would have thought, you need to think more holistically than mere dpc.

A good reply with some very salient points made, so thanks for that.

We can't render the whole of the wall as one section (the section where there is most damp, peculiarly) is only two inches from my huge oil tank - the relocating of which is highly impractical, if not nigh on impossible.

We have put a couple of Thompson's Water Seal applications and also painted with a decent exterior masonry paint, but can't render even though we would like to.

A good point about the condensation. I have already warned him that he has no ventilation bricks anywhere or even windows that could be left slightly open and, what with the washing machine, cooker etc., on the go, it is pretty inevitable that there is going to be condesation. But he seems to have turned a deaf-ear to my suggestion, preferring to blame the situation on MY side of the wall. I'm trying to help him, but he doesn't want to listen, being entirely fixated on the wall as being the problem.

Fact does remain though that the damp is most evident on that wall (whch is North facing) and particularly in the area of the oil tank (but that's just a red-herring, like as not).

Thanks again for your suggestions.

 

[kbdiy]

Presumably this wall sits on the boundary line, but who is responsible for it. The way I read your post, it's your wall so strictly speaking your neighbour should not be doing anything to it, as it doesn't belong to him.

If he has turned this area into a full-blown extension then has he done it legitimately? I suspect not as it sounds like a piecemeal development over a number of years. As such he has to like it or lump it - you have made some reasonable effort to help but 'sick purse' and 'sow's ear' spring to mind.

 

[RHGrenedier]

When you say the damp is most evident in that area, are you talking about the damp on the interior? Or is there evidence of damp on the exterior of the wall?

A vertical dpc is not possible near the oil tank, by the sound of it.

So, I think I would ask your neighbour to view your side of the wall, if he hasn't already done so, and ask him what more does he think you should do to resolve his problem.

Another tack might be to suggest that he invites a builder to assess the situation and suggest a remedy, and possibly a quote for your neighbour to consider. You might add that you are willing to allow the builder access for inspection and work but any work must be acceptable to you prior to commencement.

I would imagine that a builder would suggest that what we've already discussed and, in addition, dry lining the interior of the wall.

 

[JibT]

Thanks chaps.

There is no evidence of damp on the outside (my side) of the wall. Only internall. As said, it faces North on my side (and we all know what side of a tree moss grows, I guess).

It's a "shared" wall (in that were it to, say, fall over then any remedial work costs would be shared equally between us).

He actually offered to "pay half" (LOL) towards having my oil tank relocated (requiring ground excavation - by hand as there is no mechanical digger access, removing said material to the local dump and somehow manually moving a 2 ton oil tank, with little space to manouver, to a position which would encroach still further onto my already small garden and replace the oil tank's connecting pipework) as well as employing a builder to insert a DPC, render the wall and repaint it.

I had to gently point out to him that, from my point of view, it is already performing the function of being a garden wall, perfectly. I also hinted that, were I of an uncharitable nature, I could even refuse access to "my" side of the wall (not that I would dream of doing such).

He's getting on a bit in years and has no obvious interests other than constantly performing "improvements" to his property in a sort of "Painting-the-Forth-Bridge" style.

You've very kindly and helpfully confirmed that which I suspected which is that professional advice is probably the order of the day.

I think I'll try once more suggesting he gets some ventilation installed (I'll even do it for him as a favour as I've equally offered to erect a lean-to from under the eaves of his outhouse roof, sloping down over my oil tank so that no rain can even make contact with the wall. My argument being that, if no water makes contact with the wall then no water can pass through the wall meaning the damp's source is elsewhere - through the ground or via condensation being the most likely, if not exhaustively exclusive of potential sources). As we know, electricity generally seeks the shortest route to earth whereas water seeks the easiest - regardless of the distances involved.

Thanks again for confirming what I probably already knew but was not confident in myself enough to be sure of.

Jib.

 

[theprinceofdarkness]

your "open" side of the wall be be constantly being dried out by the wind, while his side being 100(110?)% sheltered will not dry out. Thompsons et al will only protect against driving rain not rising damp and will actually reduce the drying out. I would have a go at one of these drip drip silicone DPC injection systems.
Frank