How thick is the party wall in an 1880s stone house?

[Gary111]

I need to drill them to fit coat hooks.
Last time I tried this I remember having trouble getting a good fixing.

You can hear quite a lot through the walks so I guess they aren't very thick.

I don't want to drill right through to next doors!

 

[cross thread]

Maybe only single brick 4 inch

 

[RandomGrinch]

Are there any clues you can reference, or measurements you can make?

For example, my house has walls that come level with the internal window frame.
They are made from stone, and there's quite a depth of lime plaster in places, to make up for the unevenness.
Despite the thickness, I can still hear much that goes on next door!


At the rear of the property is an original 'extension' - as @cross thread says, this has a party wall that is only the width of a single brick.