City council calls in drones to inspect tower block housing ahead of insulation upgrade

// the building envelope

It may have surprised residents of one block of flats on Southampton City Council’s Canberra Towers estate when drones and abseilers appeared on, and around, its walls.

This was, though, not some sort of art installation but an inspection to find out whether the council’s chosen scheme to improve insulation and energy efficiency was workable and if any previously unknown problems lay within the walls.

The tower, which has 144 flats over 24 storeys, was built in the late 1960s on a concrete frame with a brick exterior and a concrete felted roof, and the degree of energy efficiency they offered to residents fell short of the council’s requirements. Ahead of the inspections, the team at Southampton had chosen external wall insulation (EWI) to deal with the issues facing Canberra Towers but wanted to be sure they had selected the correct solution. The British Board of Agrément’s subsidiary company Consultancy Investigation Training (CIT) was able to help with due diligence on this by deploying its expertise to inspect and assess the state of the tower block.

CIT was part of the BBA’s response to public concerns about poor or inappropriate cavity and external wall insulation installations in the social housing sector. CIT works on both cavity and external wall insulation, advising mainly local authorities and housing associations on ways to overcome problems.

Keith Meredith, Southampton City Council’s Programme Manager – Capital Projects (Refurbishments), explained: “We agreed for CIT to undertake independent property pre-inspections and provide relevant reports to fundamentally determine suitability for the planned works of external wall insulation, window replacement and roof replacement where applicable.”

CIT experts surveyed flats from the inside – though access was not in all cases possible depending on residents’ wishes – and used drones and where necessary abseilers to inspect the exterior of the tower. This enabled inspections to be carried out without the need for costly and disruptive scaffolding or cherry pickers; CIT estimated that scaffolding costs alone could have reached £300,000. The company also surveyed 35 council houses managed by the local authority.

CIT drones photographed the building in detail and expert surveyors examined the images to identify any issues. In the event that potential problems are identified by the drone images, abseilers can be deployed for a closer look.

The CIT inspections of the tower block revealed nothing unexpected of any importance but gave the local authority reassurance that it had chosen the correct solution to solve the problems at Canberra Towers and help address the issue of fuel poverty for tenants.

“It gave us peace of mind that our planned schedule of works would rectify the highlighted problems and, ultimately, be a wise way to spend budget, which is of utmost importance,” said Mr Meredith. “These works will extend the life of the block as they come with a 25-year guarantee.”

The EWI will involve fixing Building Regulations compliant insulation boards to the exterior of the tower block structure. These will then be covered with mesh and a weatherproof render, improving the energy efficiency and aesthetics of the building.

CIT Director Rob McCormack said: “The council planned to use EWI but required validation that it was the best course of action prior to a contractor being appointed. As well as inspecting Canberra Towers internally looking for damp, condensation and mould, we were also able to get close to the outside at high levels via the drones and abseilers, providing a close-up look at the building that would have been hard to achieve any other way. It is a really innovative service that reduces inspection costs, speeds up the inspection process and delivers peace-of-mind to clients wishing to validate their refurbishment decisions,” added Mr McCormack.

CIT services include independent CWI/EWI, condensation and damp inspections and insulation-focused stock condition surveys. Its services are available to anyone dealing with the planned installation of insulation materials or with the consequences of inappropriate insulation retrofits, or improperly installed insulation products.

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