Other roof issues

Large flat roofs constructed in concrete were a particular feature of the modernist movement. These can cause problems as the property ages. It is unlikely that the original finish will still be on the roof.

The main materials of asphalt and felts will be well beyond their expected lifespan. A well-maintained asphalt can be made to last longer, but if it has not had good solar reflective coatings it is often found to be crazed and blown. Water ingress around internal rainwater outlets can be difficult to resolve, because opening up such areas is difficult and the amount of detail the surveyor needs to observe is quite high. The main problems are where modern drainage outlets are fitted to older pipe systems, with little thought as to how the two materials will seal or move.

If a roof has had many applications of patch and liquid repairs, the surveyor needs to be aware that multiple faults may be causing a single leak. Leaks can be exacerbated by ponding, and parapets often provide many routes for wind-driven rain. If rooflights or newer vent stacks have been inserted in the roof, this may upset the existing roof structure, particularly if a large hole was made in the roof and then poorly infilled around the newer component. It is tempting to look to the surface finish as the main cause of water ingress, but something as slight as a loose coping stone or seeping rainwater outlet is just as likely to be the cause.

Older roof finishes can be damaged by too much foot traffic, including visits from roofers and surveyors. A balance has to be made between leaving alone as much of the undisturbed surface as possible, and the repair of an obvious problem. When planning repairs it is prudent to detail the work to keep as much of the roof as clear as possible, and to store materials off the roof.

When roofing felts began to emerge, they were a basic bitumen-impregnated felt with poor performance qualities compared to today's felts.

The complete replacement of the roof finish is usually the only robust option to resolve a particular problem, but financial constraints may not permit this. A remedy might not be able to wait for a landlord and tenant to agree who is to pay and when deciding on a particular remedy, the surveyor is often asked to come up with an intermediate or short-term solution.

The difficulty with this is the assessment of risk. Some liquid applications can be applied very quickly, but the issue is where to apply it and how long will it have to last? Patch repairs can make the situation worse, because they raise the surface level and interfere with water run-off. With partial replacements it can be difficult to find a useful point to join the old surface to the new.

Whichever course of action is chosen, it is important to state clearly what the limitations are and to note if this work constitutes a continuation of more remedial work on top of old, or a new remedy based on a new understanding of the defect. Options provided by a specialist contractor can be devalued by a conflict of interest. Direct supervision of any type of roof work is critical to a high-quality finish.