East Kent Hospitals University NHS Foundation Trust

Apr 7, 2021 in Case Studies, RubberBond
East Kent Hospitals University NHS Foundation Trust

Location: Canterbury
Roofing Contractor: Roptec Ltd
Project type: Refurbishment
Roof area: 240m2
System: RubberBond FleeceBack™ EPDM
Timescale: 3 weeks

Introduction

Canterbury has had a long history of providing healthcare services to the area and its origins can be traced back to the early 1790’s when a county hospital was built in the ground of a monastery in Longport.

Fast forward to the mid 1920’s and a ‘new’ art deco style building hospital was built on the outskirts of Canterbury to meet the needs of the growing population and advancements in medicine.

Ongoing Refurbishment Work

Today, while the distinctive black and white building remains, the hospital now covers a large site of interconnected buildings constructed during a large expansion programme in the 1960’s and 1970’s.

Due to their age most of the buildings were suffering with leaking roofs causing significant health and safety issues for the Trust. Most of the roofs are flat and all present different designs and build-ups.

For the past four years, main contractor Bauvill and roofing contractor Roptec have been working with the hospital on a planned refurbishment programme. When the contractors first started working with the Trust they initially inspected the site and carried out a process to grade the roofs and determine the order of work.

Maternity block

Following the programme of work, Bauvill and Roptec started work on the maternity block. The prefabricated timber frame structure had been built during the 1970’s and although only small in size the roof was suffering from numerous problems. In fact, a survey of the area identified so many different issues the biggest challenge for Roptec was knowing where to start.

The 240m2 flat roof had been constructed with low, sloped details designed to lead water towards the six internal downpipes. The existing 2mm PVC membrane had deteriorated and was failing at the seam joints. Detailing to the upstands had also failed and the internal downpipes had perished. Lastly, the roof was also enclosed by an 800mm high parapet wall which due to movement in the structure of the building had cause the joints in the coping stones to fail.

The solution

Before work could start on laying the new membrane, Roptec decided to relocate all the internal outlets to external drainage points which would minimise future blockages from the overhanging foliage. The roofing contractors first cut through the upstands to form new drainage points and then raised the internal details to ensure water discharged to the edges of the roof.

When it came to choosing the membrane, the system would have to meet a number of challenges:

– Cold roof design

– Timber framed structure would be subject to expansion and contraction during the hot and cold seasons

– A technically challenging design, incorporating four distinct areas of slope resulting in complications to a mechanically fastened system

Taking these considerations into account Roptec had no hesitation in recommending a fully adhered build-up using Flex-R’s RubberBond FleeceBack. The roofing contractors had already installed the single ply reinforced EPDM membrane on other buildings at the hospital and knew the solution could easily meet the demands of this roof.

The reinforced FleeceBack EPDM membrane is inherently flexible and would mould to the different angled edges on sloping areas. There are no plasticisers that can migrate and will remain flexible over its service life easily accommodating structural movement in the building. It can also withstand huge temperature fluctuations without suffering from thermal shock and will not crack over time.

The hospital was also wary of using any system which could cause a fire risk. Eamonn, Director at Roptec confirmed “When I first started to discuss membrane options with the hospital, the Estate Managers didn’t realise they could use a system for refurbishment work which didn’t involve hot works. They especially liked the fact that it has no fumes attached to the product, ideal on some of their roofs which have air conditioning units.”

Installation

Flex-R systems can only be purchased by contractors who are part of their Specialist Registered Installer scheme and show continuously high standards of workmanship and customer care. Contractors receive training in the systems they install and can access technical help from Flex-R throughout the project.

The specification provided by Flex-R allowed the contractor to leave the existing single ply in situ while preventing further shrinkage. A recovery board was installed before adhering the RubberBond FleeceBack membrane over, reducing labour and project timeframe. Once the membrane had been installed Roptec then paid particular attention to the capping detail on the 800mm parapet walls around the perimeter edges.

Eamonn confirms “We generally find on most projects that the lead flashing is not installed on the walls properly, which was the case at Kent & Canterbury hospital. If attention isn’t paid to every last detail ultimately it will undermine the system you’re installing.

“We were careful to add specialist metal coping as a capping detail to complete the job. This will make sure that no water would get through the parapet wall.”

Technical Support

Roptec received constant support from Flex-R throughout the project. Eamonn said “The technical advice and support from Flex-R is invaluable. This was a technically challenging project in places and it was great to know we had the involvement from Flex-R throughout. “

Matt Gurr, Contracts Manager at Bauvill agrees “We have worked with Roptec at this hospital for the past four years now and I know that they will always deliver a superior roof. Not only are they incredibly knowledgeable in the products they are working with but they also deliver the full package from health and safety considerations all the way through to snagging.

“Once you start work on the building project you find that issues will normally crop up. We know Roptec have the technical expertise and support from Flex-R to find the solution and fix the problem. As a main contractor you can’t ask for any more than that.”