Crumbling render external wall

[daztrain]

I had the original garden wall in a 1930s house refinished about 6 years ago. It has a stepped profile at the top which I wanted to retain. These are pictures (from the plasterer's website) during the job. I was very happy with the finish and painted with a couple of coats of Sandtex a month or so later, as advised.

After 2-3 years the wall began to expand and crumble at the beading on the corners. The plasterer came back in year 4/5 and repaired, reassured it would be fine, and I repainted. However, following the winter it is badly damaged again.

I want to get this sorted and willing to start from scratch but wondering if anyone can advise what might have gone wrong and what the right approach would be so I can make sure to have an informed discussion with new tradesperson.

The wall had been there for over 80 years, so doesn't seem unreasonable to expect it to hold out for a bit longer than this.

Any advice much appreciated.

 

[ree]

OP,
Typically the old render would be hacked off back to masonry - but you say, you have only done some kind of refinishing?
What kind of render mix or Brand was used?
The correct corner bead can be seen but the damp penetration seems to have started at the corner bead perhaps due to the way it was fixed and rendered into the corner.
Is the rest of the render firmly fixed without cracks?

You mention a "stepped profile" but you have a squared off capping?
It might be irrelevant:
But was anything done to the other side of the wall?
And is the lawn soil very high?
Has a car bumped the gate post?
Do you know what the white sealer?/adhesive was?

 

[daztrain]

Thanks for the reply.

The old render was knocked back and the sealant applied before the new render went on top.

The refinishing was done after the first job failed.

Grass/soil on the other side wasn't changed at any point.

Might have used the wrong term - stepped profile refers to three steps on the top of the pillars.

The render on the wall seems to be firmly affixed - problems seem to be mainly on the pillars where all of the render now sounds hollow when knocked.

Nothing has bumped against to cause damage - and all pillars in wall have similar issues.

Unfortunately I don't know what sealant or brand of render was used. Left the guy to it. Any ideas what should have been used would be welcome.

 

[ree]

OP,
SBR is the usual go-to sealant.
On all the pillars you should remove all rendering and angle beads back to exposed brick, & then start rendering again.
It might be best to slope the stepped flats to allow water to run off?