What's Behind Plaster?

[tacocat]

Hello all,

We have some damp in basement in Spain. Surveyor advised that walls had been plastered with non breathable plaster which should be removed. I've started getting rid of this but behind the plaster the wall is white in most places. It is like it has been painted, and it could be paint, although it doesn't really flake like paint. Not sure if you can tell from pics what it might be. Do I need to remove this as well? Just don't want to leave something up there that is also non breathable. Not exactly sure what the plan is after removal but might look to lime plaster it as I understand that is fully breathable.

Thanks

 

[StephenStephen]

Ask a local...
Looks like lime to me...

 

[tacocat]

Ask a local...
Looks like lime to me...

So some sort of limewash on the wall behind the plaster? Seems off they would then put on some non breathable plaster in top?

 

[Wayners]

Use to buy lime wash in bags as it's a powder.
Mix with water and brush on.
It's like a mushroom colour but dries snow white.
Was also used to mark football pitch lines back in 70s I was told

 

[StephenStephen]

As an amateur, I'm wondering if this is a situation where you do actually want water to travel through the walls or not - if it's underground then I'd think you'd want tanking rather than breathability .

 

[johnny2007]

It's very flat, could it be some sort of plaster finish in white?
Try chipping it away in a hidden place and see if you get to the bare masonry.

 

[tacocat]

As an amateur, I'm wondering if this is a situation where you do actually want water to travel through the walls or not - if it's underground then I'd think you'd want tanking rather than breathability .

Seems there are two schools of thought depending how damp it is. The surveyor when we bought the house felt the let it breathe method probably better.

 

[tacocat]

It's very flat, could it be some sort of plaster finish in white?
Try chipping it away in a hidden place and see if you get to the bare masonry.

There is actually a wall just but it which is painted white and paint flakes. I wonder if this is some sort of paint underneath but is very well bonded. It is not thick it is like a paint later and you get to masonry just below when scraping. Maybe I just bite the bullet and try to get rid of most of this as well.

 

[tacocat]

Use to buy lime wash in bags as it's a powder.
Mix with water and brush on.
It's like a mushroom colour but dries snow white.
Was also used to mark football pitch lines back in 70s I was told

Thanks. It doesn't seem to react with vinegar and maybe it should if lime?

 

[Wayners]

Lime is chalky. You can wash off with water or rub with your hand which will become white

 

[StephenStephen]

What's behind the wall?

 

[tacocat]

What's behind the wall?

It is external but as it is basement it is below ground. On that side of the house is a large hill so i presume it is earth etc.

 

[StephenStephen]

So I'm curious where the surveyor thinks the damp is going to 'breathe' through the lime to?
Lime in building helps keep the inside dry by moving water from the inside (generally higher humidity) to the outside (generally lower humidity)...

(and absorbing then releasing water - regulating humidity, but that seems less relevant here), unless you're happy with the level of damp you'd expect in a traditional basement.

 

[tacocat]

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So I'm curious where the surveyor thinks the damp is going to 'breathe' through the lime to?
Lime in building helps keep the inside dry by moving water from the inside (generally higher humidity) to the outside (generally lower humidity)...

(and absorbing then releasing water - regulating humidity, but that seems less relevant here), unless you're happy with the level of damp you'd expect in a traditional basement.

I'm most definitely no expert here but I think the idea is that moisture will come through as air vapour into room. Might be a bit more humid and a bit cellar like but that the walls would be stable. Problem I have is that current non breathable.plaster is blowing. Only other option would be full tanking I suppose