Case Study:Succeeding Where Other Roof Inspection Companies Have Failed

Spectrum were asked to investigate leaks in the roof of a tall residential building in the Capital. There was a problem with water ingress in various apartments. Despite calling out previous contractors to help with the leak detection in London, the client was no nearer getting the situation fixed.

After two individual days of operations, Spectrum were able to identify the area of the leak, as well as highlight other contributing factors to issues with the roof. We then provided the client with a report identifying remedial action and areas of further investigation.

The Project

The water was seeping into some of the top-floor apartments – an issue which had been ongoing for some time now. That’s because, although other companies had been commissioned to fix the leaks in the past, they were unable to pinpoint exactly where the difficulty lay. The result was that water ingress was becoming a real problem for householders on the top floor of the building. The client wanted to know what was causing the leak, allowing him or her to then commission contractors to fix it.

The Site

The leak was on the roof of a very tall, Grade II building, housing residential apartments in Cavendish Square, Central London. We investigated the roof and a couple of levels on the right-hand side of the building, although we believe similar issues are occurring on the left-hand side too. 

The logistics

Erecting scaffolding for a leak inspection in London would have caused a lot of disruption since the street beneath was very busy. It might also have meant obtaining a pavement licence. Carrying out intrusive surveys would have certainly meant having to ask permission. As such, it was best to avoid both the scaffolding and intrusive surveys. Instead, we used rope access work on the roof and carried out an external and internal investigation.

Portable anchors were set up to allow us access since there was no safe rigging available. Grade 3 abseilers were then able to climb safely down onto the roof and façade to assess the situation. The roof ledge was where most of the work was carried out. We used thermal imaging cameras to take readings since the ceilings were very high and difficult to take moisture readings from. It meant we didn’t have to use a ladder in residents’ apartments.

Challenges

It wasn’t just the height of the building that made this leak detection in London project challenging, there was also the fact that it was a listed property. A very prestigious, building in busy Central London, in fact. As such, we had to ensure no brickwork or architectural framework was damaged while we worked. The décor inside the properties where the water was seeping in was very luxurious. The ceilings were also very tall and using a ladder would have resulted in the walls become marked in certain areas. In terms of level of difficulty, the Spectrum team considered this an 8 out of 10.

Identifying the contributing factors 

 There were several problem areas on the roof identified by the Spectrum team. Many of these could certainly have been causing the leak difficulties to worsen over time. 

The waterproof course on the balcony was failing, for instance. While checking this, we also discovered unsecured cable housing, and which was no longer attached to the building itself. Although the cable housing wasn’t contributing to the water problems, it did require fixing.  

Other areas of concern included loose or bent leading under tiles on the 6th floor roof and several dormer windows. We were able to fix this for the client while onsite. We also spotted a number of rotting timbers on this floor and, although we couldn’t exactly pinpoint an area where the leak is occurring, we believe that the water is travelling laterally across – rather than down – the roof. 

We also spotted a number of window frames with rotting paint which could result in internal leaks in the future. 

Our investigations into balconies, gutters and windows on the fifth floor of the building showed pooling water within the gutter system. This could be the result of a lot of rain water or a blocked gutter system. Areas of flaking paint were also spotted on this floor. 

Spectrum staff noticed a void area underneath the current guttering. This is believed to be the old guttering system and there may be gullies present which is allowing rainwater to flow in and pool. 

A completely different issue was noted on the fourth-floor window areas and soffits. This involves narrow enclosed pipes, believed to be leading to directly to downpipes across the site. These may be blocked or failing during heavy rainfall. 

Recommendations

As a result of the investigation, we issued a report to the client outlining a course of action including further investigation and contract work.

We advised, for instance, on a new course of waterproofing for the balcony area, in addition to having the cable housing secured. 

Further investigation into the exact location of the leak is required on the sixth floor. Once this is pinpointed, the rotting timbers can be replaced. Similarly, the rotten window frames need sanding down and repainting.

Broken pieces of guttering require fixing on the fifth floor. The downpipes also need jetting to remove any debris. Testing should be carried out when dry to check the gutter’s waterproofing ability and which should then be fixed, if necessary. A CCTV investigation can be carried out to identify and fix any problems in the void area where the old guttering lies. A water test will also determine whether or not the joints are still in working order.