I have a 1970s built bungalow.
OK, what (I think) I understand.
I have cavity walls with brick outer and block inner
The load of the roof is taken on the inner block wall.
The problem is that on one section of wall, a crack has developed inside running diagonally from about 3ft above the floor and up to the ceiling. This is roughly below one of the major weight bearing points for the roof above.
However, there is no sign of any problem on the outer brickwork.
It looks as if there has been a crack filled before, a long time ago (10 years or more) and that this has begun to reopen. It is only around 1mm at present.
While I realise that the weight is on the inner wall, surely both walls share the same foundation and you would expect to see a problem in the outer wall if the foundation were subsiding.
Thanks for any thoughts