Permavoid Podium Deck has been specified for use within a large scale East London student accommodation project with a challenging restricted external ground area.

Working alongside main contractor Westfield Construction and M&E contractor Dimension Data Advanced Infrastructure, Polypipe helped to develop a rainwater attenuation system capable of managing the site’s drainage requirements in the event of a ‘1 in 100’ year + 30% storm event.

Although a large buried attenuation structure may have met the drainage needs of the site, a lack of external ground area made this impractical. As such Polypipe worked closely with the Environmental Protection Group (EPG) to provide a practical two-tiered attenuation system at podium level to collect water run off.

Discharge from the selected Permavoid Podium deck system was conveyed using flow control outlets leading into a small 30m3 buried attenuation tank, which was formed of Polystorm geocellular units. Using Polystorm in this way ensured that a discharge rate of 42 l/s could be maintained.

Permavoid Podium Deck provides ideal first stage rainwater interception and source control that can be easily integrated into an overall SUDS solution.

Having a 95% void ratio, Permavoid can collect and retain three times more water than aggregate sub-bases, making it ideal for projects where depths and loadings are a major consideration such as at Unite Stratford.


Glen Loftus from Dimension Data Advanced Infrastructure said:

Having to reconsider the drainage needs of the project during the build stage could have been an issue, however working with Polypipe and EPG on an appropriate podium level solution minimised disruption and went some way to making the project the success it was.

Work on the Unite Stratford ONE project completed in August 2014, allowing the building to open for its first intake of students in September. The accommodation houses more than 1,000 students across 28 floors.

Date: 07 October 2015