A properly specified warm-deck flat roof will deliver vastly improved energy efficiency over the traditional cold-deck design, whilst eliminating the risk of condensation by moving the ‘dew point’ outside of the structure. The initial investment is quickly off-set by reduced heating and cooling costs, and the resultant increased occupier comfort.
The Party Wall Act 1996 explained
The Party Wall Act 1996 came into force in 1997, so it is now law and gives you rights and responsibilities whichever the side of the 'wall' you are on i.e. whether you are planning/doing work on a relevant structure or if your neighbour is.
The Party Wall Act does not affect any requirement for Planning Permission or Building Regulation Approval for any work undertaken. Likewise, having Planning Permission and/or Building Regulation Approval does not negate the requirements under the Party Wall Act.