Black Mould on walls

[Vicci9971]

I have black mould on the shared wall in my kitchen (terraced house). It is a single skinned wall (I think this means one brick width) and was erected by the previous owners. The plaster has pulled away from the wall and has caused bubbles to form. Consequently black mould and lots and lots of woodlice have started to appear.
I have been told that the problem was caused by my next door neighbours when they installed a bathroom on the opposite side of the wall.
Looking at similar questions submitted I have two questions....

If I take plaster off the walls do I have to replaster?
If I do, must I put sealant on before or after plastering?

[cassa333]

You can take the plaster off in the area you want to and then plaster that rather than take the whole room down,

If there is damp then it would be advisable, when the plaster is off, to dry it out properly then seal it. Hopefully that way you shouldn't get the damp back.

You could ask them to check the seals on their fixtures to make sure it is water tight. Unless you are talking to then they might not realise they haven't fitted them properly.

[Vicci9971]

Thanks for your response Cassa.

Is the only purpose for replastering the walls for insulation? I ask because I cannot plaster the walls myself and the kitchen is very* cold already.
In an ideal world I would remove the plaster from the common wall, let it dry out and then paint with a sealant before painting.
What are the implications on not replastering this wall?

[cassa333]

None I would have thought. But if it is only one wall thick then plaster or a skim of some sort would be better.

Couldn't you claim on your insurance?

[buildersmate]

The purpose of plaster is to make the surface look nice - it scarcely offers any insulation value at all.
Single skin walls between dwellings are unusual. You really need to get to the bottom of where this dampness comes from - just covering it over is likely to lead to further problems every time. What has the neighbour got on the other side - a shower?
Assuming you try but you really can't prevent the damp wall, the way I'd do it would be to seal off the damp getting through by covering it 1000 gauge damp proof membrane (plastic sheet), batten it over to hold the plastic in place by using 25x38 vertical battens spaced at about 600mm apart, then nail plasterboard over that. Then you could skim the surface to get a smooth finish.
No, you can't claim on your insurance - you might be able to claim on next-door's if the damage is being caused by him.

[The Builder]

..........just to add to BM's answer..................your mould is caused by condensation.......the wall is obviously always damp and thus "cold"....................put 25mm Celotex, or similar (foam insulation board) between BM's battens to "warm" the wall