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Chetham’s School of Music, Manchester


Chetham’s School of Music is the largest Music School in the UK. RIW provided a waterproofing strategy robust enough for their new build Grade 3 basement project.

Structural Engineer: Price & Myers
Main Contractor: Sir Robert McAlpine
Principle Application: Internal Tanking
Products Used: RIW Cavity DrainRIW Sheetseal 226

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The Challenge

It was essential that the construction programme on such a large project was kept to time, so careful consideration was given to the application process of any proposed waterproofing solution. Price & Myers, the engineers responsible for the specification of waterproofing on the project, were also conscious that when applying a Type A system externally, a methodical application and attention to detail were critical. 

The initial concept looked at using a Type A bentonite tanking system applied externally. However it was soon established that this approach would be time consuming, mainly due to complex detailing and the level of attention needed during application.

The Solution

The waterproofing strategy was revisited and it was agreed that a drained cavity solution would be more appropriate. RIW Cavity Drain was chosen, as this would both meet the requirements of a Grade 3 basement and allow the groundwork’s concrete frame to be constructed quickly, without the need for a stop-start process. 

Once the mainframe was constructed, the basement waterproofing was installed. The application was quickly completed and the robustness of the product allowed subsequent trades to work in and around the application, without risk of damage to the membrane. The mainstay of the application took place during winter; RIW Cavity Drain’s temperature tolerance meant that there were no delays in installation due to cold weather.

RIW Sheetseal 226 was then used as a waterproof membrane at wall floor junctions, column details and service entries, followed by RIW Toughseal and RIW LAC to damp proof service trenches and lift pits.

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