Wildernesse House - Retirement home renovation

9 January 2020


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

The Project

The scope of works was to provide extensive renovation works to Wildernesse House, a Grade II listed Georgian House. Within the specification was the requirement to provide watertight living quarters to the basement of this extraordinary property. Wildernesse House required modernisation to transform it into a luxurious boutique retirement home. Delta registered installers, Timberwise (UK) Limited were called upon to offer a waterproofing design to meet the requirements of BS 8102:2009 to achieve a dry habitable living space, defined as a grade 3 environment.


The basement to Wildernesse House is constructed from traditional stone and brick with the slab floor being cast of concrete. On the initial site visit, the previous waterproofing installation was evident, however the structure was damp from ingressing moisture. Due to Wildernesse House being Grade II listed a waterproofing system that was suitable for heritage structures was required. Delta’s Type C Drained System was a perfect solution with its sympathetic reversible ‘air gap’ technology which would be suitable for Grade 1 & 2 heritage structures as the system may be removed without damaging the structure. 

Phase 1
Initially Timberwise’s technicians undertook repointing works. Over time the decay within Wildernesse House’s basement had allowed undesirable water ingress. All large holes found in the brickwork were sealed in preparation for the waterproofing system. Prior to the installation of the Type C system, an application of Koster Polysil TG 500 was applied. Koster Polysil TG 500 is an anti-lime inhibiter which reduces the amount of free lime leaching into the Cavity Drainage System.

Following the curing of the Koster Polysil TG 500, 2 coats of Koster NB1 was applied. Koster NB1 is a mineral coated waterproofing slurry which is ideal for sealing brickwork against pressurized water ingress. The Delta MS Cavity Drain System was installed to the walls and vaulted ceiling with perimeter drainage set into the basement slab.

The all-important inspection ports were added at approximately 8 linear metre intervals to ensure that the drainage aspects would be fully maintainable and in accordance with BS 8102:2009.

Phase 2
Phase 2 of the project was to a different area of the basement. This area had earth retaining walls which meant there was a lot of hydrostatic water pressure bearing against the structure.
As with Phase 1, repointing works were undertaken.

Any large holes found in the pointing were sealed in preparation for the waterproofing system. The substrates were then treated with Koster Polysil TG 500 anti-lime inhibitor, which also improves the water resistance of the basement structure by absorbing into the structure and locking in the free lime.

Two coats of Koster NB1 Grey were applied. Koster NB1 is suitable for waterproofing against ground moisture and for non-pressurized and pressurized water up to > 13 bar.


The client was delighted with Timberwise’s pragmatic and practical approach to this project, ensuring that Wildernesse House will be preserved for years to come, given Delta’s 100-year product life cycle.
Wildernesse House is designed to bring people together to enjoy all the estate has to offer, creating a happy and relaxing retirement home. 

System Components

  • Koster Polysil TG 500
  • Koster NB 1 Grey
  • MS 500
  • MS 20
  • Delta Channel

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