After an extensive research programme, Marshalls Civils & Drainage introduced the 1200mm Perfect Manhole system to the UK in October 2009 to meet the challenges of modern day construction. Today, the sealed manhole system is available in 1200mm, 1500mm and 1800mm and comprises of a monolithic precast concrete base (available pre-benched in any configuration), a sealed chamber ring (with thicker walls than traditional rings), a rubber joint and a sealed cover slab.
