External render and damp problem

[soniam]

Hi, I have been told we have hydroscopic damp. It started in Jan due to all that rain. But apparently the first floor hallway window was not sealed properly when it had been installed by the builder last year (who I have not been able to get hold of and have not seen since last summer).
The external render he did was rubbish too.

Various builders have suggested to either:
- sand the outside and put on two layers of paint
- scratch and plaster over
- remove and redo the render (quotes varied from 5-7k)
Which is best to do?

Then the inside would need to be done.
Is it best to remove plaster and redo or sand it then paint? Anything special need to be put on?
This damp is also in the baby's room which was ready last summer (she was born in Jan) but I did not want her sleeping in that room.

There are damp patches along the attic staircase - outside the paint has been peeling which had been done about ten years ago.

Thank you.

 

[Micilin]

Without seeing it I think you need to apply new render to seal up, if there is no other ingress.

Hard to say whether this involves taking off the old stuff without knowing if it is sound.

 

[soniam]

A bit hard to see in pictures but if you rub external render in some places it's like dust coming off, it is def uneven on the side wall.