Basement waterproofing as part of a £5 million refurbishment in Liverpool

Client: John Turner Constructions Ltd

Products Used: cavity drain membrane, sump pumps, perimeter drainage channel


The Reader is a national charity that aims to build warm and lively communities by bringing people together so that everyone can experience and enjoy great literature. Situated in the beautiful surroundings of Calderstones Park in Liverpool, lies Calderstones Mansion House. Built-in 1828 for Joseph Need Walker, the house was then used in a variety of ways to include offices of the Liverpool Corporation and Gardens department as well as a tearoom and wedding venue. Calderstones Park has been the home of The Reader since 2011, and in 2013 the charity signed a 125-year lease to become custodians of the Mansion House. The house was then awarded a £5 million refurbishment with fund support from Heritage Lottery Fund and Liverpool City Council.

Carried out over three phases a full renovation of Calderstones Mansion House was transformed the Mansion House, Coach House and Stable Yard into a book shop, community events space, a theatre room, a large modern café, reading rooms, heritage rooms and office space.

John Turner Construction called upon the Waterproofing Design Specialists at Timberwise to design and install a basement waterproofing system to create dry living space, archive storage and kitchens within the large basement at the property. Being a listed building of sympathetic design was of great importance.

Waterproofing Design Methodology

It was clear from the survey that the void areas in question had over the years been subject to varying amounts of flooding and excess resistance, and therefore Timberwise were required to design a system to the main parts of the basement allowing a variety of uses that would also be impervious to any future incoming water.

Due to the age of the building and the nature of construction, an initial floor slab was installed. The lime leaking from new concrete needed to be considered before any waterproofing installation could commence ensuring that any future deposits could not solidify and potentially block the free flow of water.

Timberwise treated the floor slab and the immediate areas above with a lime inhibitor, thus ensuring that no further deposits could manifest themselves and become a hindrance to the proposed waterproofing system.

Due to the size and complexity of the room structures and to respect the buildings Grade II listed status, Timberwise decided that it would be necessary for a complete cavity drain membrane system, along with three subfloor sump and pumps.

Before works could commence Timberwise required sight of the asbestos register to ensure that an asbestos survey was correctly preformed and any areas that need to be disturbed (in particular old pipework and boxing) would not contain any asbestos-related materials. Timberwise also made the customer aware that due to the nature of the conversion they would need to consider adequate heating and ventilation. The client advised that they were having a completely new air control system installed within the building.

  As a Cheshire based company with roots in Liverpool, we pride ourselves in being local Waterproofing Design Specialists and have been involved in many local schemes in Merseyside, so it was a pleasure to be part of the Mansion House restoration project in the historic Calderstones Park. We are proud to be part of the wider team, to bring the house back to its former glory so The Reader can continue their work for the people and communities of Liverpool.

. – Timberwise Waterproofing Design Specialist

As part of the pre-installation preparation works, the contractors created channels for the new perimeter drainage as well as the three apertures necessary for the installation of the sump and pump systems. The customer also prepared the supply of all necessary electrics required to power the sump pumps.

The cavity drain membrane was then installed to the vertical walls and horizontal floor surfaces. Timberwise also membraned the barrel vault ceilings to create a totally waterproof subfloor void thereby ensuring that no matter where the water came from it was contained only behind the membrane surface, thus draining into the newly installed perimeter channels and ultimately into the sump and pump chambers for discharge externally.

Because of the existence of lime and other natural water deposits, we designed within the system several inspection ports to ensure that the system could be adequately maintained and periodically cleaned to maintain the free/uninterrupted flow of water throughout the entire subfloor drainage system.

This installation required a constant line of communication between Timberwise and the other contractors on site to ensure that all the necessary preparatory works had been undertaken to the correct specification.

It was also important to express the “dos and the don’ts” of the dry lining system that was also installed. It was vital that it did not puncture any of the membrane installed thereby breaching what was a totally waterproof installation. The waterproofing installation was a complex piece of work, but ultimately the customer was delighted, and we turned what was previously, unused and unloved damp and musty large belowground cellar into a dry warm and usable space.


Timberwise created a dry habitable space for newly transformed kitchens, safe archives living rooms and a communal corridor for the mansion house (events and performance centre). The Mansion House then opened its doors to the public again after a 3 year and £5m restoration.

Speak to a Waterproofing Design Specialist in Liverpool

All our basement solutions also benefit from our design and installation services along with our long-term insurance backed guarantees ensuring you have complete peace of mind that your basement will remain dry for the year to come.

You can trust Timberwise to provide you with the right basement waterproofing systems to suit your project. Don’t hesitate to contact Timberwise via our form above, by calling on 0800 288 8660 or you can request a survey online.