The Gunnery, Kent

28 June 2017


Basement type: Refurbishment Building type: Residential
Type of waterproofing: Type A Member: Delta Membrane Systems
Other: Heritage  

The Project

Universal Basement Waterproofing were first approached in November 2016 to assist on the transformation of an unused fort/home on a 92ft cliff edge in Kingsdown, Kent. Delta technical consultant Kevin Dodds was also invited to assist with Universal Basement Waterproofing's unique project.

The Gunnery was originally a military base with extended underground rooms and thought to have ‘secret rooms’ underground. The building had suffered from fire damage as well as vandalism over the years and had been left to ruin.

Universal Basement Waterproofing gave careful consideration to detail and logistics. The first phase being demolition. Over a period of 8 weeks over 200 tonnes of construction waste was removed from site ready to make way for the second waterproofing phase.

The Solution

The second phase on the project was how to ensure the building was watertight ready for development. The waterproofing needed to achieve a Grade 3 waterproof environment in accordance with Table 2 BS 8102:2009. The structure was built to withstand bomb attacks and some of the concrete structure is in excess of 500mm thick. Built into chalk, a naturally well draining substrate, water ingress was only one of the issues, as condensation in the underground rooms needed attention.  

Following site inspection and discussions on the various options available through Delta’s extensive range of products, the following products were deemed most appropriate:

Cracks within the concrete floor: Köster 2IN1 injection resin. The Köster 2In1 injection resin has 3 objectives, to restore the aesthetics of a building, to stop moisture entering cracks and to achieve structural repair.

Wall/floor joint: It was recommended to use an angle grind to chase back into the joint followed by application of Köster KD Blitz to wet and damp joints, followed by application of Köster Polysil TG500 and an initial application of NB1 to approximately 150mm either side of each joint and over KD Blitz application. Once cured a further application of Köster Repair mortar plus as a minimum 30mm fillet was packed into the joint. Followed by 2 further coats of Köster NB1.

Wall/wall and Wall/soffit joints: Here Köster polysil TG500 was followed by a 1st coat Köster NB1 (150mm either side of joints) was applied, then 30mm fillet Köster Repair Mortar Plus – packed into the joint. Once cured applying 2 coats of Köster NB1 were applied.

Expansion joints: These were cleaned of any loose dust and debris, with an application of Köster Polsil to joint areas then filled with Köster KB FLEX 200, following the application of the Köster NB1 throughout.


The finished product is a luxury dwelling which offers panoramic views of the beautiful coastline and even the coast of France on good days!

See Delta Membranes Systems company profile