As the Building Owner you have to give written notice to your adjoining owners at least 2 months before you start any party wall works. For line of junction or excavation works the notice should be at least one month.
NOTE: It is advisable to talk to your neighbour prior to giving them a written notice so that they are prepared for it when they receive it. Please also ensure that you discuss your work in detail prior to issuing the notice. Once the notice is served, your neighbours should respond in writing to your notice within 14 days of the date you have issued it so that any potential problems can be resolved in time.
Please also ensure that you give notice to anyone living above or below your property and if they are the tenant, you must also ensure that you inform the landlord.