The British Museum Conference and Exhibition CentreWorking on deep basement structures can often be challenging. Add a retaining structure of secant piles combined with a high water table to the mix, and you’ve really upped the ante.
At RIW we often deal with grade 3 basements, each one presenting new challenges. So when it came to the British Museum extension, which needed a strategy to ensure protection of the priceless artefacts from ground water ingress, the task was just as great as ever.
Having been contacted for the job following our previous work with Careys plc, the project coordinator, and Rogers Stirk Harbour + Partners, the Architect, we were awarded the £400,000 contract at pre-contract stage. Through approaching us so early in the project lifecycle, it enabled collaboration at the design stage where we provided scheme specific CAD details and construction drawings. Helping to ensure a waterproofing system that suits the building’s needs as the programme progressed.
The initial issue faced at the British Museum extension site – which has been built as a conference and exhibition centre – was the high water table in the four-storey deep basement structure. Solved first with the installation of RIW Structureseal beneath the reinforced concrete basement slab, which created an impervious layer based on bentonite clay through swelling to form a monolithic waterproof barrier.
However, to further protect the building along the horizontal slabs and secant piles, Cavity Drain R7 was used in conjunction with the heavier duty version, Cavity Drain R20. This flexible studded membrane meets the standards to achieve a Grade 3 (BS8102:2009) basement. This is through being designed to collect water entering the structure and channelling it to a sump or collection point for disposal.
When looking to seal the Cavity Drain it was vital to ensure the system drains into channels that are all linked to sumps, which are then periodically emptied by automatic pumps. To achieve this for the British Museum conference centre we utilised Sheetseal 226, and Toughseal to help form watertight joints through draining into channels linked to sumps that are periodically emptied by automatic pumps.
Due to the sensitivity of the project application, our approved specialist waterproofing contractor Cast Contracting Limited (CCL) installed the waterproofing and liaised closely with us throughout.
The new Conference and Exhibition Centre at the British Museum is now open to the public, housing a large collection of historical objects and providing event space.
For more information on the products used for the British Museum extension or to talk to someone from our Technical Team regarding RIW services, call 01753 944200.
By Martin Radford, Business Manager at RIW Ltd.
