Party Wall Appointment
Finchley, London N3
Close to Golders Green, Hendon and Hampstead. With the catchment of our Finchley office.
Background: The works required excavation for basement works within 3 m of one of the adjoining owners' property and below the level of the foundations of the neighbouring house on one side, and of an existing retaining wall on the other side.
The appointment was made by the building owner. The adjoining owners did not wish to appoint the building owner's Surveyor as Agreed Surveyor and instead appointed their own Surveyors.
There were two adjoining owners.
The works involved excavation to enlarge and deepen an existing basement and create a new lightwell.
Conclusion:
The works involved excavating below the existing footprint of the building in order to enlarge the existing basement and to excavate it to a deeper level. This required that retaining walls be installed to either side and the two Awards addressed this and other related matters.
It was also proposed to lower the level of the side passageway so that it would match the level of the new lowered level of the basement floor. Although there was an existing retaining wall to the side passageway (pictured) to support the adjoining owner's higher land, the result of lowering the building owner's land would require that a new retaining wall on deeper foundations be installed. It was proposed that the new retaining wall would abut the existing one and run alongside it.
The Award required that the new retaining wall be prevented from bonding with the existing wall by installing a slip membrane, that flashing should be installed where the two walls abut and that the foundations for the new retaining wall should be excavated in hit and miss sequenced bays so that its foundations should not become undermined.