Blonde Hedgehog hotel - Cellar waterproofing

9 January 2020


Basement type: Refurbishment Building type: Leisure
Type of waterproofing: Type C Member: Delta Membrane Systems

The Project

Encircled by the quiet cobblestoned streets of Saint Anne that lead to Alderney’s dramatic coastlines, is The Blonde Hedgehog. Originally a public house, it has been developed into a luxurious gastropub and hotel. Delta registered installers, Oaks Damp Proofing were commissioned to design and install a cavity drain waterproofing system that would meet BS 8102:2009 to the cellar area.


After undertaking site inspections to the structure, a Type C Cavity Drainage System was recommended. The cellar area was fully earth retaining and borders the main road which meant there was a lot of hydrostatic water pressure bearing against the structure.

To reduce risk and slow down the volume of water entering the structure, the walls of the cellar were treated with the Koster KD System. The main contractor incorporated a new basement slab to the cellar which allowed for incorporation of the Dual V3 Sump Pump and channel recess. Prior to the installation of the Delta Type C System all new concrete was treated with Koster Polysil TG 500, an anti-lime inhibitor.

Preceding the installation of the Type C cavity drainage system, Oaks ensured the waterproofing design would easily be maintainable and repairable. The benefits of using a Type C cavity drainage system enables the management of any water ingress in a controlled process. Any moisture or running water ingress travels behind the membrane to be diverted to a Delta Submersible Pump, meeting allowing for the required Grade 3 environment.


The Blonde Hedgehog’s cellar has been converted from an unused room into a desirable relaxation area for diners and hotel guests. By incorporating a Delta Type C cavity drainage system, the cellar is completely protected against water ingress.

System Components

  • Delta MS 20
  • Delta MS 500
  • Delta Cornerstrip
  • Delta Plugs
  • Koster KD System
  • Dual V3 Sump Pump
  • Delta Channel

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