Basement waterproofing for a mill conversion in Leeds

Client: Yelcon Homes & Scotfield Group

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


Yeadon near Leeds is an area steeped in history and Naylor Jennings Dye works, previously known as the Green Lane Mill, is an original weaving mill and dye-works situated at the heart of this famous Leeds borough.

Green Lane Mill was built in around 1868 and the main building was destroyed by a fire in 1906 before being taken over by Naylor Jennings and converted to a dye works. The dye works were to be transformed into high spec apartments and the surrounding outbuildings to luxury housing.

The site comprised of approximately 15 acres with the historic mill buildings and their large brick & stone chimneys as well as several cottages dotted around the site. The existing buildings had basements which the developers wanted to use for both habitable and dry storage purposes.

Empty for some time, and due to a lack of maintenance, the site was prone to water ingress and therefore required a robust waterproofing design system.

The client called upon Timberwise’s expertise to guide them as to what levels the basements needed to reach to achieve the criteria within the British Standards – “Code of Practice for Protection of Below Ground Structures Against Water from the Ground” (BS8102:2009) and to satisfy Local Authority Building Control (LABC) warranty, providers.

To achieve the grade 2 and grade 3 environments required by the customer, Timberwise specified and installed a Type C waterproofing system.

What do you mean by waterproofing grades?

The waterproofing grade rating is defined by BS8102:2009, the grades relate to how effective the waterproofing system needs to be depending on the existing environment and the result of the project.

Grade 1

Some water seepage and damp are tolerable depending, suitable for areas such as car parks or bin stores.

Grade 2

Water penetration is not acceptable however, damp areas are tolerable – boiler rooms, workshops etc.

Grade 3

Water penetration and dampness are not acceptable, the basement must also be ventilated. This is common in areas that are to be used as habitation in both residential and commercial areas such as homes, offices, shops etc.

BS8102:2009 states that a Type C drained protection type of construction is considered the most effective and trouble-free form of waterproofing. The basic principle is that the walls and floor are lined with the membrane which effectively allows water in and therefore equalises any hydrostatic pressure.

Once the water has entered the building behind the membrane it will drain away through a series of perimeter drainage channels and into a sunken sump and pump chamber. The pumps would then pump away the water to an external source as and when water reaches a predetermined level within the sump chamber.

The walls and the floor were entirely lined with a dimpled membrane which was fixed by special sealing plugs and a variety of butyl tapes and ropes which are necessary to provide a vapour barrier.

This development is the touching distance from our Timberwise Branch and provides a country-like setting mixed with the convenience of city living.

With Timberwise covering the area for over 50 years, Timberwise has gained a reputation for repair and restoration of locally listed buildings, we’re happy to be part of the project and helping to deliver more high-quality homes in the local area.  

. – Timberwise Waterproofing Design Specialist

The installation also included pump alarms to advise of any failure and a battery backup system to immediately activate in the event of a loss of mains power.

The internal surfaces of the walls were then plastered with a free-standing plasterboard system. 8mm cavity drain membranes to interior walls and 20mm membrane to the floors it also incorporated peripheral drainage channels within the basements which takes water to the pumping stations with dual pumps and battery back up to achieve both grades 2 and 3 environments.

Did you know?

Following negotiations for the redevelopment, it was agreed that a watercourse would be installed. This was due to the loss of the mill ponds, in order to promote and maintain local ecology and provide woodland that can continue to be enjoyed by all.


Timberwise was able to handover to the client, fit for purpose basements so they were able to continue the renovation works.

When complete, the scheme will provide contemporary apartments and housing all with unique characteristics, including refurbished cast iron columns ready for 21st-century living. Work on the site started in 2016 and construction of the first phase of the development was completed in 2017.

Speak to a Waterproofing Design Specialist

You can trust Timberwise to provide you with the right waterproofing solution to damp problems in your building. Don’t hesitate to contact Timberwise by calling on 0800 288 8660 or you can request a survey.