Waterproofing and Flood Protection for a Period Watermill, Kent

When it comes to flooding, nothing can prepare for the devastation and destruction that is caused by flood waters inside a property.

For the owners of this historic watermill in Tunbridge Wells, Kent, this prospect became a reality after winter storms brought high levels of rainfall to the area.

The flood was the result of a perfect storm of environmental and geographical conditions. The property itself is built into a bank and earth-retaining, making it more at risk from ground water penetration. Furthermore, the parallel access road is also 4-metres higher than the ground floor level.

Lastly, the stream that traditionally powered the old mill is directed through the bank and under the access road via 1-metre wide concrete pipes. During periods of heavy rainfall these pipes can restrict the flow of water downstream, creating a serious flood risk for the adjacent mill.

In the aftermath of the New Years flood, the owners needed a permanent solution to protect themselves and their property.

The Project

Following the floods, the property underwent a full strip-out as part of the insurance restoration. The owners then approached Newton Specialist Contractor Stonehouse to design, install and guarantee a flood-resilient system to protect their home. Stonehouse are no strangers to protecting properties from flooding, so they were the ideal contractor to deliver a permanent and maintainable solution.

The Solution

The first step was to reduce the old building’s permeability and decrease the potential water ingress during future floods. Stonehouse applied water-resistant plaster to all brick walls, linked to the concrete floor with Newton’s cementitious waterproof barrier membrane, HydroCoat 103 2K.

The second form of defence was a full internal CDM System, known as cavity drain waterproofing. This maintainable solution used a combination of the 508R membrane to provide robust protection on the walls, and 520 eco Floor membrane to give a high drainage capacity across the floor.

Captured water is directed to three Titan-Pro sump chambers cast into the floor, each containing two NP eco 750 pumps. The system has a potential pumping capacity of over 1,500 litres/minute, with three Newton battery back-up systems delivering complete peace of mind in case of power outages.

The Result

The complete and guaranteed system, alongside new flood-resistant doors, has provided reassurance to the owners, keeping their home completely dry during further flood events.