Background:

Teesside International Airport in the North East lies across the boroughs of Darlington and Stockton-on-Tees. The site was originally an RAF airfield during the Second World War before starting commercial operations under local authority control in the mid-1960s providing services to both the local business community and leisure passengers. Twenty years later the airport moved into private ownership however, in 2019, the airport moved back in public ownership after 16 years in the private sector.

In 2020, the airport was awarded a £25M investment for the development of two new hangars, Jet Centre, business park plus much-needed refurbishment work. One of these refurbishment areas included refurbished roofs to the air traffic control tower and surrounding buildings.

Roofing product choice:

In total, the roof spaces sit on four different levels and each one had been laid with asphalt. Due to the nature and high security surrounding the airport refurbishing the roofs with bitumen was not a viable option. Northern Roofing & Cladding Services worked with AccuRoof, part of SIG Roofing to determine the best waterproofing covering. Constraints on the site meant that no hot works would be allowed but the concrete structures also meant that mechanically fixing were not an option. The roofs were in a bad state of disrepair and there was significant water ingress into the control tower. Remedial work over the years had seen repairs patch up gaps within the asphalt.

The original specification brief was to use a liquid waterproofing system on all the 600m2 roof areas, but as the project had initially been delayed due to the wet weather conditions in 2023, and to keep the project on track Northern Roofing & Cladding Services worked Accuroof to consider alternative solutions no so weather dependent. The decision was made to install a PVC roof system on some of the roof areas while liquid waterproofing was used on the two areas which, due the roof and its condition, made it too difficult to work with a PVC.

The product selection for the area requiring liquid waterproofing were:

SIGnature Liquid Waterproofing – Ultra Protect

VCL – SIGnature Ultra Protect AVCL / carrier membrane

Insulation – Tissue Faced PIR 150mm thick to achieve 0.16 u-value adhered with IKOpro High Performance PU adhesive

Carrier membrane – SIGnature Ultra Protect AVCL / carrier membrane

The team at Northern Roofing & Cladding services were supported on the project by AccuRoof, as they are part of their Roofing Contractor (ARRC) scheme. This enables them to install their specialist roofing systems if they are trained on their products and regularly assessed on the quality of their work. This provided the client with peace of mind on the quality of the work. The contractors also had support in their installation work as the system had been designed, supplied and guaranteed by AccuRoof.

Installation:

The smallest of the area requiring a liquid roofing solution was the hexagon shaped air traffic control tower which is approximately 100 sq.m. The roof on this tower had been leaking for at least a year with water entering into the important strategic area below. Restrictions because of the nature of the control tower, meant no hot works were allowed on the roof. Due to the poor condition of the roof and the flexibility to strip the space, the contractor first stripped back the roof before laying an 18mm OSB over a profiled metal deck to achieve a minimum of 1:80 falls at any point.

The contractor then applied the SIGnature Ultra Protect AVLC and SIGnature Ultra Protect approved insulation at 150mm thickness to achieve 0.16 u-value which were adhered with the IKOpro High Performance PU adhesive. The insulation boards were then primed and an AVL applied before installing the liquid waterproofing topped with the strand matting. Once cured, a second layer of the liquid waterproofing was applied.

Sitting below the windows of the tower’s control room is a perimeter platform which also had asphalt that had failed over time. With no living areas below, the area did not require insulation. However, The structure is made from concrete which made any mechanical fixing too difficult.

The surface on this area was mottled and bubbly, laying down boards and installing a different roofing system would not have achieved the desired outcome whereas a liquid system can work into the nooks and crannies to create a flat surface and instantly waterproof the space. To install the waterproofing, the roof area was initially jet washed off and a fungicidal wash used to ensure they achieved a clean surface.

The team then applied a primer to the clean area, which when dry they applied an undercoat layer and topped this with the strand matting. Once cured, a second layer of the liquid waterproofing was applied.

Installation challenges:

This was a challenging projects for the contractor Northern Roofing & Cladding Services, not because of the complexity of the roof but due to the additional logistical constraints.

The first problem was due to ensuring that a detailed plan of works was put in place. With the air traffic control tower being on the airport side, any visitors to the site had to undergo rigorous security checks. Time had to be allocated to ensure every contractor was vetted and issued security passes before work started. To enter the site each contractor would have to go through security before commencing work.

Due to the age of the building, logistical and environmental conditions it was imperative that any waterproofing system used would adhere correctly. To ensure a successful outcome, AccuRoof technicians visited the site about 20 times to perform sampling of the roof areas.

Once work started on site, careful planning was required to get the materials to site. Northern Roofing & Cladding Services would have to inform security and the airport manager of any deliveries and then provide them with exact details on the products being delivered, the vehicle registration and delivery time. The local SIG Roofing branch responsible for deliveries, worked closely with the roofing contractors to help them meet these exact requirements.

To meet Health & Safety requirement, including working around a busy airport, the team would receive safety briefings every day and they worked closely with the airport staff to minimise any disruption.

The management at Teesside International Airport has been so impressed with the work of Northern Roofing they have now won a contract to commence work on a new hangar.

Images: