Some more damp questions...

[jungle_jim01]

Feels like it's been a damp year! I'm just thankful we've only got damp and not floods to contend with.
I know most folks like pictures so here's a couple more of the latest challenge. (apologies for all the junk in shot!)

Problem 1: The wall junction: So i'm working in the lean to. And one corner is particularly damp (most of the way up). I'm going to check the gutters aren't leaking next time it rains (shouldn't have to wait too long!) but it doesn't look like the 2 walls are tied together and there is a slight gap on the outside so it's possible that water is finding it's way in. Once again it seems to have stood the test of time so not sure i need to fix ties in (??), but i do need to make the joint watertight. I was thinking maybe mortar unless there's something better i should be putting in there.

Problem 2: The outside patio is a good ft or so above the inside floor. This is an extension and probably originally the wall wasn't built for being in a living space. I'm thinking of a French drain (again) on the outside...which leads to another question: is it possible to patio over a French drain? The outside wall is also pointed in lime above patio level, so that should help a little. This is going to be a kitchen and the area is going to be behind a sink unit so 'out of sight' but i don't want a damp problem and mould to build up. Once again any suggestions on tackling the issue very welcome...kind of a 'what would you do inside and out question?

Sorry for all the questions lately...i've got a bit of time off so cracking on with the next part of the project! but thanks as usual for all the helpful advice.

 

[jungle_jim01]

Happy new year to everyone
I'm thinking of leaving the end wall exposed stone pointed in lime below counter top level. My thinking is that at least that way the walls can breathe and damp can evaporate away. I'm wondering if that's likely to create a problem in terms of mould growth or whether i can apply some kind of fungicide to the wall? Any suggestions always welcome

 

[Zebra]

I'm thinking of a French drain (again) on the outside...which leads to another question: is it possible to patio over a French drain?

I'm no expert but from experience I would recommend if at all possible, digging the ground away, building a small retaining wall a short distance, say six inches away from the wall, and not filling it in.
I built a French drain, with proper drainage in the bottom, filled with gravel, and it didn't work because although water drained away, it didn't allow sufficient air to circulate close to the wall to make a difference to the dampness in the wall.
It turned out in my case the French drain was never going to be enough to combat the problem and more drastic measures were needed anyway, but if it is your own land and you can do it, I'd suggest that an open gully will be more effective than a French drain. You can always cover it over with some grating.
In answer to your question can you patio over it, again, this will cut down the effectiveness of the French drain because although water can drain away, no air can circulate to allow the wall to dry. So if you are going to create a French drain, I'd suggest that you fill it with as large an aggregate as possible so that you can get some air circulating in it. Gravel is too small. Someone else on here used beach pebbles successfully. All you can do is try one thing, see if it works and if it doesn't, try another.