Ongoing leak/damp issue in one corner of leasehold flat

eevamaija

Hi all, just looking for a bit of advice. I bought a leasehold flat (first time buyer) a couple of years ago, knowing that there was a leak/damp issue in two corners of the flat from two different balconies creating a bit of a flat roof above my flat (stupid design). I was assured the problem was being dealt with. On one side of the flat the problem has actually been dealt with and hasn't recurred. The other side is a different story. 

The recurring leak shows as a patch of damp on the ceiling and wall after heavy rain. I've raised it every time it has recurred, which is now about five times in two years. I haven't redecorated because I wanted to be sure the problem was resolved - which of course it hasn't been. So I have a fair amount of damp and plaster damage in this corner, although it is not covering a big area.

The building management who take care of this for the freeholder (also the building is a co-op, which confuses me a bit, I admit - this seems to complicate things if I want to make an insurance claim, which so far I haven't) have in fact tried to resolve the problem on each occasion. I have been sent photos of repairs and details. I have really pressed them to investigate the matter fully because I know leaks can be complicated. But on every occasion, four or six or nine months later (or on a few occasions, immediately after the work has apparently been done) the leak/damp recurs in the same place, always after heavy rains. I think the work has mainly been done on the balcony itself and I wonder if the brick wall at the edge is letting water through somehow. 

I know that if I redecorate the damp is probably going to come through again as it hasn't been permanently fixed on any occasion (not even "permanently" as in, for a few years). On the other hand, I really need/want to redecorate and don't want to live with this stupid damaged corner forever. 

The flat is perfectly liveable, especially as this isn't a leak with water actually dripping through. And the leak/damp was rectified on the other side of the flat and hasn't recurred (yet...) so fixing the problem should be do-able. Any suggestions? I don't want to sell/move out because I like the place and the location. It has a bunch of stuff needing doing to it (a fairly long list, but largely cosmetic) and I've kind of been putting it off partly because I wanted to get this issue resolved. 

I can keep hassling the freeholder and they're responsive enough to do some work on it but I can't help feeling they're not taking it seriously because surely such a leak that always occurs after heavy rain, and similar to the one resolved on the other side of the flat, should be fixeable. Any suggestions? If I just have to redecorate bearing in mind that the damp/leak will probably happen again, do you have any suggestions about that? Many thanks!