The
HMV flagship store in Oxford Street, London was subjected to severe
flooding to the right hand flank wall at basement level, which saturated
the carpet in the Classical section of the store.
Customers
were literally splashing water over their shoes as they browsed. The cause
of the flooding was a combination of ground water ingress, a leaking fire
hydrant, rainwater seeping through the external pavement lights and
blocked drains.
A
single solution was needed to overcome all the problems. A cavity
drain membrane was installed to the walls of the affected area, stretched
diagonally across the soffit (using metal fast track battening to support
the soffit membrane and prevent bulging) in order to catch any further
seepage through the pavement lights. An internal peripheral drainage
channel was set into the slab at the wall/floor junction to drain all the
collected water into a sump chamber, which had a dual pumping system and
alarm. The collected water was then pumped out up to ground floor level
into the existing drainage system.
After
completion of the works and following a routine visit to the store during
torrential rain, the pumps were removing significant amounts of water,
leaving the store completely dry. Previously that amount of rain would
have resulted in several millimetres of standing water in the basement
section of the shop.
This case
study has been submitted by a member and the British Structural
Waterproofing Association accepts no responsibility for its content.
