Delivering challenging waterproofing contracts by Proteus

It's not about the size of contract that matters, but very often it is the sheer logistics of the project and how it can be delivered. Such was the case at the Radio City Tower in Liverpool, a building, 138 metres tall, offering breath-taking panoramic views of the surrounding city with a highly complex ‘flying saucer’ roof under 1,000 sq metres. 

This iconic skyscraper is frequently used for charity and abseiling events and can only be maintained by operatives using rope harnesses. Over the last 20 years, the use of ropes had significantly damaged the integrity of the original waterproofing, as well as the naturally fragile and friable Foam Glass insulation. The existing waterproofing membrane had broken down at the exposed edges, breaching the waterproofing membrane.

A waterproofing challenge of this complexity could not be met by conventional roofing contractors. Specialist roofing and general contractors, Orb Rope Access Ltd, were chosen as they had previous knowledge of the building, working at extreme heights, and as Proteus Approved contractors, were trained in the use of the company’s cold applied liquid systems. 

This incredibly unique project possessed many design and installation challenges. To meet the client’s requirements of a fully repaired and resilient waterproofing system and prevent the insulation being crushed again, a protective timber upstand ring was designed, made at roof level, and installed to the top of the roof edge detail. 

Individual bespoke pieces of plywood had to be measured, cut, and bonded to fit the undulating vertical face above windows, and another piece bonded around the perimeter of the domed circular roof to form a firm corner where previous damage had occurred. 

Once the ply was cut, the exact pieces had to be taken to the correct location around the edge of the roof and bonded into place before the Pro-Prime® SA and Pro-Vapour Control/Carrier Membrane SA could be applied. Proteus Pro-System® was overlayed to provide the ultimate watertight protection. 

Applying waterproofing at such height comes with an abundance of challenges. Weather conditions substantially differ at height, making wind and rain speed incredibly intense. Wind proved to be the greatest challenge. This was especially prevalent when applying the carrier membrane and fibre glass where the wind made the final application incredibly difficult. Being such a tall structure, the tower naturally sways in windier weather, further adding to the challenge.  

As well as securely harnessing themselves to the building, the contractors had to ensure all tools and products were also firmly secure to avoid any items falling from the roof. These were clipped to the operatives’ harnesses as they were dangling over the edge 130m in the air making waterproofing application and movement around the roof perimeter incredibly difficult.

Delivering safety in crowded areas

A different contract and a different type of challenge – this time the need for extreme safety for both contractors and pedestrians at Hay’s Galleria near London Bridge. Originally a warehouse and associated wharf (Hay's Wharf) for the port of London, this Grade II listed structure was redeveloped in the 1980s and at the time, was one of the largest construction projects in the country. 

Hays Galleria is made of two opposite facing buildings connected by a large, elaborate, glass atrium providing an enclosed courtyard. It contains greenery, water features and large sculptures including ‘The Navigators’, a bronze ship sculpture that immortalizes the Galleria’s shipping origin. 

To preserve this historic gem and protect it from deterioration, the client required a preventative maintenance programme to the gutters and 2,400 square metres of standing seam roof areas, extending the lifespan of the zinc roof sheets and metal box gutters serving the atrium. Roofing contractor, Millane Contract Services Ltd, was chosen to deliver the project.

This elaborate project possessed many design and installation challenges. Throughout the roofing works the shopping mall below had to be kept open, therefore, safety was paramount. To ensure nothing could fall from the roof to the internal floor, a protective netting system was designed and installed 3m - 4m to the underside of the whole roof area. 

This design was made more demanding as the central section of the roof is a large, delicate glass atrium meaning the netting system needed to be strong enough to hold a pane of glass that could potentially dislodge and fall. 

Stringent testing of the debris netting was carried out on a test rig prior to work commencement. The same specification of 2.5m x 1.5m glass panel was dropped from a scissor lift at increased heights between 3m and 4m to ensure the reinforced glass panels would not break through and injure members of the public below.

A 2-ply high strength safety catch net was also installed to protect areas beneath the pitched roofs and guttering. Each bay included a vertical front face to prevent material falling through the side arches as well as the area in plan. The protection was installed over the length of one side of the roof, then repositioned in one operation to suit the progress of the guttering repairs.

Due to the complexity of the building design, scaffolding was essential. Before works could commence, access towers were installed to the external face of the building at a height of 24 metres from the floor and were located in areas that were least disruptive to the businesses and pedestrians using the building. 

The installation was carried out by rope access teams in conjunction with the scaffolding contractors.  Once the scaffolding and safety netting was installed, the preparation works could commence. This involved selecting low odour products, also crucial for minimising disruption. Proteus Pro-System® Plus is a low odour, cold applied liquid meaning residents and businesses were not affected by the smell of strong fumes, making it ideal for the project. 

Collaboratively, Proteus Waterproofing and Millane Contracts Ltd successfully delivered this project to an impeccable standard over a four-month period resulting in one incredibly satisfied client, and another fully protected, long lasting, watertight project. 

They don’t come much tougher

They don’t come much tougher than a car park over the basement roof of a 17th century London prison. The grounds of Kingsway Place, north-east of Clerkenwell Green, has a long and turbulent history stretching back to 1617, including destruction by fire in the 1780 Gordon Riots. 

Two prisons once stood on this historic ground, Clerkenwell Bridewell, for sentenced prisoners, and The New Prison, for individuals awaiting trial. In 1794 The Bridewell shut its doors, and by 1847, the New Prison was completely renovated and renamed as The Clerkenwell House of Detention. 

Within forty years of opening, the prison was demolished almost in its entirety. All that remained were the basements, incorporated into the site’s next use as the Hugh Myddelton School. Throughout World War II, the old basements were reopened for public use as air raid shelters. 

In 1971, upon Hugh Myddelton School’s closure, the building was sold to Persimmon Homes and transformed into a Grade II, luxury apartment and office building, now known as Kingsway Place.  The 9,000 square foot vaults beneath, known as the "Clerkenwell Catacombs", are no longer open to the public, but have been used for several films and TV series’ including ‘The Halcyon’ and the iconic ‘Sherlock Holmes’. 

These precious, historic vaults are situated underneath a 1,300 square metre car park servicing nearby properties and businesses in the City’s Clerkenwell area.  Due to previous poorly installed waterproofing, the car park required extreme refurbishment and waterproofing works. 

The defective waterproofing was allowing water ingress into the structure below causing erosion and green fungus decay to the brick surfaces. The proposed works included forming a solid structure over the 17th century brick vaults with falls to a drainage collection system, fully waterproofed with Proteus Waterproofing’s exclusive Cold Melt® system. 

Although situated at ground level, this 1,300 square metre car park concealed a hidden treasure – the original 17th century remains of the old Clerkenwell House of Detention. The existing surface was gently broken away revealing the historic structure and an abundance of challenges. The ground floor prison cell floors were exposed with deep voids down to the vaulted ceiling. This meant the structural designs had to be revisited and a substantial Civil Engineering Scheme was required to protect the structure and fill the voids. 

The vaults underneath the car park area were measured and mapped out with a Robotic Total Station to form a point-cloud map. This map was converted into a 3D model and layered with the new roof structure to make sure all the cambers and falls could be created without damaging the historic structure. 

MJ Rooney and the engineers were able to redesign a suitable substrate for the vaulted ceiling to include a reinforced concrete cambered slab with perimeter curbs to channel the water to outlets, solving problems ahead of construction.

Once the old substrate had been carefully removed, the newly designed reinforced concrete base, perimeter curbs and outlets were installed, and the waterproofing works could commence.

However, the design changes to the structure meant valuable time was lost and the construction programme was behind schedule. Worse, the newly poured concrete being laid in the winter months would now struggle to cure enough in 28 days to be overlaid, further delaying the construction programme causing large financial costs to the contactor.

To bring the programme back on schedule, Cold Melt® DPM Primer was first installed over the green concrete after only 3 days. The concrete below the primer, now protected from the elements, was allowed to continue its chemical hydration process and cure in its own time. 

Once the Cold Melt® DPM primer had cured overnight, it provided a dry surface for the Cold Melt® waterproofing system to be laid. Pro-Prime® SA and Pro-Vapour Control/Carrier Membrane SA were applied to allow for the final application of Cold Melt®. 

This waterproofing process allows trapped moisture to escape naturally overtime and is proven to create a stronger concrete base, giving the substrate a seamless and robust waterproofing protection and a lifetime guarantee as specified by the BBA. 

Cold Melt® was the perfect system for this incredibly complex project. As it is liquid applied, it allowed for a seamless and fast application to all the vertical and horizontal surfaces, and complex detailing around the outlets. 

As well as exhibiting extremely low odour, Cold Melt® is cold applied and therefore completely eliminates the risk of fire, offering numerous benefits to both the installer and residents. It incorporates recycled rubber crumb, castor oil and other organically grown products making it one of the greenest systems of its kind, meeting and exceeding every health and safety requirement.

Three challenges and three successful installations – with contracts they said could not be done. We are now looking forward to the next challenge