Challenge

Kent House, a multi-million pound listed property in Hammersmith, overlooking the Thames, was being completely refurbished and extended to create a large modern home, while retaining original architectural features of the original 1760's design.

A large proportion of the project was below ground level and situated just a few metres from the River Thames, meaning that a robust and reliable waterproofing approach was essential.

Newton specialist basement contractor, Wing Waterproofing was commissioned to undertake the project.

The building had a series of vaulted arches and brick walls to the front, which were underpinned to create extra living space.

Solution

To the rear of the property a very large RC concrete box was cast to provide a new subterranean living space, along with a large swimming pool.

Wing Waterproofing used Newton 101F as a cementitious Type A barrier system across all underpinned sections to provide a resistance to water coming through the dry pack elements. New-build joints in the RC box were protected by Newton 303 PolyProof water bars encased in the new shuttered box in all the vaulted areas.

Newton 508 membrane was installed and batten-hung off the plugs. Any water would be diverted to the Newton Basedrain channel, fitted around the perimeter of the entire structure.

Prior to the membrane system being installed, a new RC slab was installed throughout both elements of construction. The engineered slab had concrete sumps formed within the structure as a means of capturing the water that entered the system and to be removed via mechanical means.

Newton 906 Lime Inhibitor was used on the slab, with 50mm of closed cell insulation installed as a spacer, and the Newton 508 membrane was installed with a 65 screed with underfloor heating to finish.

Outcome

New and existing building elements were waterproofed to a Grade 3 habitable environment in accordance with BS 8102:2009. This project was in an extremely high risk area being very close to the Thames, so the skill of the main contractor working with NSBC Wing Waterproofing ensured that the client got a watertight structure.

The projection of the joints with the contingency of the cavity drain means the system is 'maintainable', which is a prerequisite when designing waterproofing systems to BS 8102:2009.

Wing Waterproofing took PI on the design and installation so the client has an insurance-backed guarantee for all works.