We are Building a Separate Flat in Our Loft Space, Complete with a New Stairwell. Do We Need to Serve a Party Wall Notice?

Question

We currently live in an Edwardian detached flat – we occupy the upstairs and the stairway – the neighbours occupy the downstairs flat.
 
We are building a new 1 bed separate flat in the loft space. The only impact we think this will have is a stairwell being put in – which would lay on our floor (does this need party wall notice?) and then we will need to erect scaffolding around the whole building, including on their private land.
 
Please can you let me know what party wall issues are included in this and what points I must give notice and get consent for?
Also do I need this before Planning Permission is given or can I do this after – and if so – is it 2 months or 14 days prior to work commencing.

Answer

Unless the construction of the staircase involves cutting in to a party structure (wall or floor) between the 2 properties the work will not be notifiable to the downstairs neighbour under the Party Wall Act.

Presumably you have a Freeholder? It is likely that you will have to obtain a license to alter from the Freeholder and part of that process will usually involve ensuring that the downstairs neighbour does not suffer unnecessary inconvenience and that a record of the condition of their property is recorded in case of damage – check the details of your lease.