On 01/02/2014 15:40, Tim Watts wrote:

Cut plaster off the affected area back to brick. Sock out any tar with
tissue paper soaked in sugar soap - repeat over a week, leaving tissue
paper stuck to brick until dry. That draws some out.

Render with a 3:1 sand cement mix as the plaster "undercoat". It's less
permeable than plaster.

Seal that (he didn't, I would)

Skim plaster.



Thanks. I'm hoping it won't come to that.

Another Dave