On 18/05/2018 10:41, Andrew Gabriel wrote:
In article ,
David writes:
Slightly more complicated bit is where (especially in 1930s properties)
all the internal walls are masonry.

In that case I assume that you need to check that there isn't another wall
directly above.

Walls don't only provide vertical support, but also lateral support.
This can be more true of internal walls than external walls, as the
internal walls have fewer openings for doors and windows, which
seriously weaken any lateral support provided.

There is the famous case of a terrace of houses. One by one, they
removed an internal supporting wall and supported the structure
above with an RSJ or similar. It wasn't until the last house
removed this wall that all the lateral support had gone, and they
collapsed sideways.


I think it was Bristol and it was row of terraced houses on
a significant slope. Each house removed massive internal chimneys
but when the end house did the same, problems occurred.

Also somewhere in Croydon something similar occurred but that may
have been subsidence where an entire terrace built on a slope,
gradually slipped down the hill.