A roof is one of the biggest asset management risks that facilities managers face, and a site condition survey will help to maintain this important 'out of sight' asset, says Daren Fraser.
07 October 2019 | Daren Fraser
1 Repair or replace?
To effectively manage the roof, it pays to commission a full site condition survey. The survey will demonstrate whether refurbishment is required or provide reassurance that remedial work is not needed.
A proactive prevention plan can then be determined as the condition of the roof is known, contributing to cost certainty when managing and maintaining the asset.
For example, an ageing flat roof can have its life extended cost-effectively if given the attention it needs in good time.
Conversely, without an in-depth investigation refurbishment costs could be higher as solutions are found only when an issue becomes apparent. For example, water ingress over time could cause structural damage, but costs would be accounted for if prevention measures were included in a maintenance plan. Any unknown defects or degradation could cause more problems at a later date - demanding immediate action and unplanned costs.
2 Compliant technical data
A professional site condition survey should be carried out by a technical roofing system specialist who will assess each roof area using core samples, this will include evidential support and possibly other investigations such as moisture readings to assess potential water ingress. Once done, this will inform a comprehensive overview of the condition of the roof.
The survey should provide details of the roof systems that have been used, their condition, evidence of any exposure to the elements, previous repair condition and any other urgent concerns.
A specialist will be able to predict the expected life of each area of the roof, taking in account environmental factors such as UV rays.
3 Assess all aspects of roof design
The condition survey and any subsequent cost for repairs should consider and address in detail all elements of the roof. This includes perimeter details, detailing around penetrations or any complex architectural features. In addition, any facilities such as roof plant outlets for HVAC systems should be factored in, as should the location of demarcated walkways for foot traffic of maintenance trades.
4 The impact of associated components
If major repairs or a replacement are necessary, it is crucial that associated services and components are considered. For example, the design needs to ensure that any changes to the roof's waterproofing system do not exceed the capacity of the existing drainage system.
A roof specification may include the use of tapered insulation to create a fall towards roof outlets or gutters to reduce ponding, for example. While this will create a faster run-off, insufficient drainage could lead to an above-capacity water-flow rate, which, in turn, could cause problems with water ingress, resulting in further costly repair works.
5 Think about access
As part of the survey and during subsequent inspections, the roof areas will be checked to guarantee full compliance with health and safety and building rules.
Flat roof areas may need to be accessed to carry out maintenance of rooftop equipment, such as air conditioning plant and ventilation systems. A site survey will be able to identify any potential hazards such as fragile roofs, as well as the presence and condition of safety equipment on the roof such as guard rails and fall arrest systems in line with Approved Document K: Protection From Falling, Collision and Impact. FMs have a duty of care to make sure walkways and access systems are maintained correctly to provide safe access for people working on the roof. Correct materials and systems should be specified to meet these requirements, so the membrane must be resistant to mechanical damage from foot traffic and feature a slip-inhibiting finish.
Roofs rarely fail without warning; problems tend to develop over long periods. Determining a comprehensive maintenance plan that includes regular inspections based on a full site condition survey will help FMs to plan budgets effectively and with certainty, and understand the condition of all areas of all roofs to prevent unscheduled remedial work.
Daren Fraser is head of technical at Langley Waterproofing Systems