How could I fix up some old plaster

Question

I'm in a house where the plaster was done in an old style. Not lath-and-plaster as one of the tags suggests but simply plaster mixed in with hay or something fibrous on top of brick.

With the humidity this has gradually started to turn to dust in two places. Downstairs this is happening in the corner of a wall and, upstairs, a piece of ceiling just under the attic has practically fallen. This can become a problem downstairs as the red bricks underneath could also soak up humidity and falling to eventually degrade too.

It was suggested that I use some tinfoil (?) then replaster but this sounds weird. How could I redo this properly? Get rid of all the plaster that's loose and put some new plaster in or use gyproc panels instead?

Answer 1

In older structural brick buildings, it was relatively common to plaster directly to the exterior brick walls. Most of this plaster has successfully held for 100+ years, so if you were to simply remove the loose plaster and re-plaster I would imagine that it would hold for quite a long time as well.

However it plastering is a bit of a lost art and can be very time consuming and expensive. You could also install some furring strips directly over the existing walls and ceilings and drywall.

I guess the decision would depend on if your goal is to retain the current plaster, or simply to have functional walls and ceilings. It almost always works out to be less expensive to install furring strips and drywall. Also depending on the situation this gives you an opportunity to add some insulation.