Damp Outside wall

[Clickem]

I have a low garden wall which is shared with my neighbour. It is about 750mm high and built of 9inch brick. The land is low lying, heavy clay with a high water table and the wall, although about 50 years old is solid, but tatty and mouldy

//www.diynot.com/network/Clickem/albums/

Since taking the photo I have cleaned it up and painted it with white masonary paint, but 4 months later it is bursting out in a few placed and has green mould on it. Someone has drilled some small holes through the centre of some of the bottom row of bricks, and after heavy rain, water runs out of the holes

I don't think that it has a dampproof course, although the wall does becomes the party wall between our garages, and that has damp proofing and while the wall in the garage is not as damp it does also tends to blister and the paint peel

The wall is a retaining wall for my neighbours drive, which is about a foot higher than mine, it also has a car port structure on it. So I am limited in that I cannot dig out the back of it or dismantle it

1. Is there anything that I can do to stop the damp ie tanking

2. Should I make larger holes through the bottom of the wall and put some small pipes in to drain the water away?

3. Is there a better outdoor paint that I could use to stop the mould growth?

4 Any other ideas

TIA

 

[dann09]

Post some pics showing both sides of the wall,from ground level to top of the wall, and a pic, towards the house, of the full length of the wall.
Indicate where the holes are.

 

[Clickem]

I have added another 3 photos to my album showing the full length of the wall running up to my garage, my drive and my neighbours drive to show the different levels, and the bottom rows of bricks with the drain holes in

//www.diynot.com/network/Clickem/albums/

Is there a way of showing the images in the message rather than through a link?

 

[dann09]

1. The holes appear to be failed, historic DPC pressure injection holes.

2. If there is a mechanical DPC in-situ then its being bridged on either side of the wall by the brick paving.

3. What you have is simple rising damp - moisture from the ground and the hard, drive surfaces.

4. Perhaps the brickwork is sodden and any treatment will be blown off in a short time.

5. You will have to live with it, the wall will last for ??? But if you wish to rebuild/replace it, then come back here for how to.