Recommended wall sealer?

[tmiker]

We live in an 1850's house constructed of solid ~1m thick solid stone walls. The pictures show residual damage caused by a leak, which is now fully resolved, today the wall is not damp. However, as per the pictures there continues to be some kind of reactions going on in the wall causing paint to blow off the wall, and corner beading to become corroded. I tried all kinds of sealer, rust removal/preventer, all so for have not worked. Short of hacking off all the plaster, is there anything on the market that can seal the wall and prevent these outbreaks? Or any other ideas? If I tiled the wall without any kind of treatment, will they eventually fail?

 

[Wayners]

Houses that age have wooden corner bead. Fitting a metal one will cause it to rust so fit a plastic one.
Plastic beads are available at most DIY stores and Screwfix etc.
You can buy lime plaster repair filler online in small quantities of Travis sell limelite.
Then you need paint that won't trap moisture. Modern paints have PVA (vinyl) that will seal wall causing the moisture to build up pushing off the paint.
You may have to remove paint from the problem areas and use emulsion suitable for lime plaster.