Finding the source of damp in a Manchester apartment

Living in a part of the world which has plenty of rain, issues concerning damp and water damage are some of the most common jobs we get called to assess. We are well experienced in finding the source and remedying faults in buildings, so when we are called to assess brown staining from water damage, we are in a great position to get to the root of the problem and come up with a plan to fix things.

We got called to an apartment in Newton Heath in Manchester over the summer of 2021 with a report of plaster/decoration damage, black mould contamination and brown water staining in the hallway walls and ceiling. Not particularly nice for the residents and not great for the building either.

Being methodical when investigating leaks and damp damage is important in order to fix problems and allow redecoration so we started with an initial inspection of the interior of the property and its exterior too. There are a few ways which we can track down causes of damp and leaks depending on the placement and type of damage. This time we chose to use a thermal imaging survey and moisture mapping of the internal space to start with. Thermal imaging cameras are a great non-invasive way of checking hard to reach areas – it picks up those parts of the building which are damp by way of the temperature. These cameras are a fantastic tool for showing heat-leakage and damage to roofs.

In this instance, the thermal imaging camera didn’t show up any problem points, this was due to the weather being dry and no damp areas present during the moisture mapping internally.

Unfortunately we were unable to gain access after water testing the roof with the occupant being absent, however, an external examination of the roof revealed some valuable information which helped us to nail down some of the causes of the leaks.

Inspecting the external areas is a crucial part of diagnosing water ingress and when we checked the roof of this building, it showed a built-up type construction flat roof with ply membranes, asphalt and gravel ballast. The fall detail was directed towards the centre of the roof and it had 2 water outlets.

Regular checks to flat roofs are important, membranes can become damaged and water ingress can rapidly cause damage if the surface fails. Common problems with flat roofs can include the collection of debris like dead leaves and soil, both of which can block the escape of water to the guttering and cause ponding on the surface.

During our inspection of this particular building’s roof, we found quite a few historic repairs, which had utilised many different techniques; liquid membrane, torch, felt, etc. most of these had failed or at the very least, in the process of failing. There were repairs to damage as well as in locations where there were penetrations like the soil stacks.

Not all damaged roofs need replacing entirely, however in this case we felt that it did need extensive work which, in the long run, might’ve been more expensive than a full re-fit. We found that gravel was missing or sparse in areas and because of the missing cover from the gravel, the asphalt had been exposed to UV light and this had damaged it and caused crazing (cracking) on the protective surface.

Further inspection showed us that the essential gradient of the roof wasn’t consistent and some areas had pooling where water was not draining away. “Ponding” can cause additional and excessive weight to the structure of a roof meaning that if there is further water leakage to the building, the interior damage can be greater because of the larger volume of water involved. Pooled water on a flat roof can only evaporate, not drain away and can cause extra deposits of debris. Finally there were gaps around felt collars encircling the different penetrations such as the soil stacks. These were all candidates for water access.

Ultimately, the condition of the roof was poor. There were multiple areas which could contribute to the damp inside the building and it was difficult to accurately say which of these defects was causing the leak.

We recommended to the owner of the building that they replaced the roofing rather than patching up the existing damage. This way they could ensure that the water ingress would be dealt with and repair work would be minimal over the years ahead. The alternative would be to carry out dry electronic leak detection and repair any defects found, however given the existing state of the roof, it would be likely that more work would be required in the near future and it would cost more than a full replacement.