Will removing modern plaster damage internal 18thC bricks?

[Kathy]

There are cracks on an internal wall and a mystery damp spot near the ceiling. I asked a builder to remove existing plaster and use lime.. Now having some thoughts -

I don't know if the bricks are 18thC or modern (this house was owned by a builder in the 60's who made changes but details not available) so now thinking to start by just removing the plaster near the ceiling to see what it going on (and hope nothing major, no plumbing above, builder thinks it could just be damp coursing its way from a nearby outside wall).

It will also show whether the bricks are old or modern and whether the wall was plastered in lime or gypsum. If the bricks are modern and the wall is gypsum then no point using lime, however if bricks are 18thC but have been plastered with gypsum I am concerned removing it all will seriously damage them. In which case would it be better to keep any areas where the plaster (whatever it is) is sound and just focus on taking it off the dodgy areas and repairing whatever the wall with whatever it has been plastered with? If the wall was plastered with lime (doubt it ) is that still a good approach?

Appreciate your thoughts. Thanks.

 

[skierhughes]

It depends on whether the wall has been built using modern methods, ie cavity, or if it was built using traditional methods, solid.
It doesn't matter whether the bricks are modern or old.
You need to use the materials suited to the method of build, so solid wall lime, cavity wall gypsum.

If you remove it with care then you can minimise the damage, but there will be some damage.
You need to balance this against the damage being done staying on. As you already have some damage (damp), I'd be inspecting as you've said to determine mode of build and then act accordingly.