New Wall being Built Against the Party Wall to Build a two Storey Extension and Neighbours wish to Build Overhand.

Question

We live in a semi-detached cottage and the at the rear the kitchen wall on our side includes a party wall between our 7 year old single storey extension and our neighbours downstairs bathroom.
 
They have planning permission for a part two storey, part one storey extension. The two storey is proposed to be build directly against the party wall with the single storey element being approximately 100mm from the boundary and 150mm from our extension flank wall.
 
We are 11 months into trying to get the party wall award sorted and have had no less than 5 notices as the party wall surveyors have attempted to get a solution for the two storey element.
 
The neighbours have stated that they do not need access to build the two storey extension and will build overhand. This is despite us saying that we are happy for them to put scaffolding over our glass roof extension for our own safety.
 
The party wall surveyors have said that they do not believe the extension can be built without access but that it is not a party wall matter.
 
Our question is whether the new two storey cavity wall that is being built directly against the party wall should be deemed notifiable works and therefore the neighbours can be forced to put proper scaffolding in place and not build overhand.

Answer

The building of a new wall against a party wall is not notifiable so the appointed surveyors do not have any jurisdiction over working methods.

I’m assuming that your neighbours are trying to save the expense of erecting scaffolding over your extension. Building overhand is a common practice where access is difficult and should not endanger the workers provided there is a safe scaffold on one side of the wall. It would be impossible to do it without allowing mortar to fall on to the surface of your roof.

Could it be agreed that your roof be covered with plywood laid over polystyrene and be cleaned down at your neighbours expense once that part of the work is complete. Although the building of the wall is not notifiable your neighbour will still be responsible for any damage caused so should be keen to protect the roof.