Product / system manufacture
Product / system supply
South East England
John Simpson & Partners; Bidwells
RIW Cavity Drain R20, RIW Toughseal, RIW MultiJoint
Peterhouse College, the oldest college at the University of Cambridge, commissioned John Simpson Architects Ltd to develop a masterplan for the historic area of the College and design a new building and extend existing buildings in order to provide additional facilities within the College.
The main waterproofing requirements were for a full basement to the new build extension; waterproofing continuity was then required between the new and existing basement.
A completely dry environment (Grade 3, BS: 8102) was required for the basement area, with various dampproofing requirements above ground, requiring the tanking to link up to the DPCs for full continuity of the system.
As the design and build contractor placed high importance on the project being kept on programme, it was desirable to use a system that was quick and easy to install.
Due to the internal required environment, it was decided that a dual tanking system was necessary. A decision was taken to use a watertight concrete to provide Type B integral protection, with RIW Cavity Drain R20 used over the watertight concrete slab and walls to control any potential water ingress. Any water collected by the RIW Cavity Drain system was then to be pumped back out of the basement.
RIW Toughseal was used extensively to provide dampproofing around the basement soffit and to the base of partition walls that penetrated the RIW Cavity Drain system. At the partition walls RIW Aggregate Grade 1 was broadcast into the second coat of Toughseal to provide a key for finishes.
At the joint between the new and existing basement, RIW Multijoint and RIW Cementjoint were used to provide waterproofing continuity. Above ground level a mixture of two RIW liquid membranes (Toughseal and Flexiseal) were used to provide continuity to DPC levels, and dampproofing as required. RIW Sheetseal 9000 was also used in some locations as a DPC.