Bert Coules wrote:

I have to find the exact centre line of the party wall which divides two
semi-detached bungalows. Unfortunately, internal and external changes over
the years mean that simply measuring between the nearest windows on each
property and dividing by two won't necessarily give an accurate result.

Like others, I am finding it a bit hard to get my head round the
situation.

Can we assume that the party wall is in one plane?

Do you know, or can you estimate its thickness?

Can you measure to the wall internally so as to transfer its
position externally?

You suggest that the windows are no longer symmetrical, but they
should at least permit you to be able to chalk up externally
where the internal edge of the wall lies.

If you can't do this, perhaps you need some more professional
surveying equipment, and/or someone to operate it.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.