I agree with aP ask the builders to stop work and inform the house owners that you have not received the party wall notice to sign nor have you had a copy of the schedule of works and you have requested work stops on the party wall.
Ask the builder to inform his client you wish to speak to them on this matter
Make a note of the builder name, time date, etc.
Should they do so, 🙂
Stress that you are happy for the work to be done, but you must protect your own interests should you wish to sell the house in the future.
Point out a local search will turn up ‘building regulations’ approval for their work. Removing a chimney breast and extending an existing extension by about 3ft may not require planning but will have to conform to building regulations.
That may affect the future sale of your property
a) reduced value if works have not got full approval
b) delay the sale process – you may lose a sale
If they chose not to contact you then 😥
Approach the planning office in your local council and ask what is going on, are they aware of the work, have building regulations been approved and issued. Does the extension require planning approval?
Ask for a building inspector to visit the house, beware if they have acted rashly he is more than likely place a prohibition notice stopping any works.
Contact your solicitor or a party wall specialist.
I can remember cases where people have knocked down wall, etc and the house has become unstable and in extreme cases required demolition