Concrete Basement Gas Protection

Summary

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  Maclennan and Prestige Air fitted the duct around the basement that would deliver the positive air curtain.

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  Drainage channels around the perimeter provided a means of directing captured water, as well as gas

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  The finished system requires perfect seals around all penetrations, and is extensively tested before sign-off.

Searchfield Homes developed this £15,000,000 five-bedroom mansion in leafy Windlesham, Surrey. Complete with a four-metre-deep basement housing a swimming pool and spa pool, requiring protection from water ingress and ground gases. Radon gas protection for basements is critical.

The Project

The architect contacted Newton Specialist Contractor MacLennan Waterproofing due to the property’s prestigious nature. The site also presented a high water table and ground gas risks. MacLennan provided a combined waterproofing and ground gas remediation specification. The team also delivered an insurance-backed installation guarantee.

The Solution

Maclennan recommended the patented Newton PAC-500 System to protect against both gas and water ingress. The PAC-500 begins the Newton CDM System by MacLennan’s installers, who have obtained or are working towards their Level 2 NVQ qualification. The team installed Newton 508 membrane to the walls and floor, using MultiPlugs, and sealed the joints with Waterseal Tape. The system then directs water captured by the membrane through a series of Basedrain and Floordrain channels to a Titan-Pro sump and pump chamber.

MacLennan worked closely with specialist gas remediation contractor Prestige Air during the installation process. Together, they converted the CDM system into a Positive Air Curtain (PAC) system. The team installed an air duct behind the membrane at ceiling height around the basement, before using a high-volume, low-pressure fan to deliver a continuous curtain of air.
This pressurised airflow blocks ground gas entry behind the membrane.

The Result

By utilising the specialist expertise of both MacLennan and Prestige Air from an early stage, the architect and client benefited from a combined system that not only protects against both water and gas, but is also compliant with all relevant British Standards and supported by MacLennan’s insurance-backed installation guarantee.