I had a retaining wall built in my garden last year. It is concrete block that was then rendered.

I painted it with ordinary masonry paint in the Summer and over Winter about 1/4 of the paint blistered and loosened.
I have removed all of the loose paint with a wire brush, some of the paint had what looked like fluffy white mould behind it attached to the wall, (effluorescence?).

My question relates to how I should remedy the problem. Obviously masonry paint on its own won't do the job so I have the option of treating the wall as if it were garden furniture, wire brushing and repainting each Spring, about a 3 hour job, or some kind of alternative.

Someone I know suggested Unibonding the wall before repainting with masonry paint but this can't be good for the wall can it? Sealing in damp, surely it's better to let the damp pass through to maintain the integrity of the wall.

I have done some research and found a paint product that doesn't create a seal and bonds with the cement in the render, it's called Durbocem and sounds like it'd do the job but it doesn't come cheap, £90.00 for 10 litres, which is the amount I would need.
Does anyone have any other, more costs effective ideas, that would solve the problem.
I don't mean to sound like a skinflint but if we were to have a particularly hard Winter, not unheard of recently, and the render blew and had to be removed and re-rendered then I'd be shelling out for another tin of Durbocem.

Any suggestions would be greatly appreciated.
Thanks,
Sean

You can't normally paint most bricks with masonry paint unless you stabilise the bricks first using a stabilising solution, or else you get the exact problems that you have described.

I'd scrape off what you can, perhaps even use a wire brush then treat the whole surface with something like this-

http://tinyurl.com/6l9h7mq


Before re-applying the masonry paint.

_________________
DIY | Donnas dream house