Party Wall Act - are the downstairs neighbours an Adjoining Owner?

[poptwig]

Hi
I am a part-time developer, developing a first floor maisonette and have received both planning consent and building control (full plan) approval for a loft conversion.
I served notice on the occupiers/owners of the g-floor flat beneath mine and the g & 1st-floor flats on either side. 5 notices in all.
The four either side approved, G-floor occupants dissented, so we both appointed surveyors as required. Their surveyor is now saying he thinks the Act does not apply to them / us because the party wall has to separate my property from theirs and it does not. They own the lower portion of the Party Wall, us the upper meaning its not a party structure in respect of us/them. He says the only party structure between us/them is the floor/ceiling and we are not touching that.
I disagree. The Party Wall Act says:
“adjoining owner” and “adjoining occupier” respectively mean any owner and any occupier of land, buildings, storeys or rooms adjoining those of the building owner
if we are proposing notifiable work to a party wall (we are) then we have to serve notice on all adjoining owners according to the Act.
Therefore, I believe the notice we served on the g-floor occupants is valid. Am I right?

[mk1fan]

Firstly, there's no requirement to appoint two surveyors. An Agreed Surveyor would have been an acceptable choice.

Regarding your notice. Assuming you're inserting structural beams in to the party wall to support the additional floor. My view would be that as you are altering the structural conditon of the wall and adding to the load it needs to bear then notice will be required in order to protect your position.