IKO Whitepaper: Periodic roof maintenance

A flat roof protects us against wind and weather, provided there is good follow-up maintenance.
What is the best approach to take? What are the key aspects of good roof care?
You can read it all in this technical dossier.

Roof maintenance requires proper attention as it is
one of the factors which:

  • influences life expectancy
  • ensures continuous good drainage of the roof surface
  • ensures optimum performance of the waterproofing
  • limits the stress on the roof structure
  • maintains optimum performance of the insulation
  • ensures the roof’s insurability

Maintenance Contract

In Belgium and most neighbouring countries, standard-setting bodies recommend or require roof maintenance.

The Belgian Association of Contractors of Waterproofing Works for instance provides a ‘Roof Sealing Maintenance Contract’ to its members.
In the Netherlands for example, owners are required to maintain their roof frequently and effectively. In particular, two season-specific maintenance inspections are prescribed: One after the leaves have fallen, and one after the winter. The maintenance is preferably
carried out by the contractor who applied the waterproofing based on a maintenance contract.

A good maintenance contract lays down the necessary tasks (according to the aforementioned norm) and, as such, describes the nature and scope of the maintenance at an agreed price per m².

Poor roof maintenance may result in ‘foreseeable’ damage which, consequently, is not insurable. The IKO warranty insurance policy requires a minimum of 1 maintenance inspection per year.

Execution of Roof Maintenance

Proper maintenance of flat roofs guarantees proper drainage and waterproofness of the roof.
To that end, the following action must be taken:

  • Cleaning of visible surfaces
  • Cleaning of rainwater drains and application of an anticorrosion coating, where appropriate
  • Complete inspection of visible waterproofing works and execution of small maintenance repairs
  • Inspection and, if necessary, repair of flashings and profiles
  • During the first roof maintenance, one must ascertain whether the capacity of the rainwater drainage system
    complies with the norms in terms of overloading of the bearing structure.

The type of maintenance is season-specific:

After the winter

After the leaves have fallen:

Primarily preventive maintenance, inspection and cleaning:

  • general inspection and repair of the waterproofing, if necessary (wrinkling, sagging, ageing, coming loose,…)
  • inspection of the discharges, drains, gutters, gargoyles, tube and cable passages, protective layer, if any, flashings, coping slabs, sections, jointing etc.
  • apply additional protection in heavy-traffic areas, if necessary
  • in the case of ballasted roof systems (warm roof and inverted roof), adjust the ballast, if necessary

Primarily cleaning:

  • removal of fallen leaves
  • removal of moss, vegetation, foreign objects etc.
  • in the case of ballasted roof systems, adjust the ballast, if necessary.


  • Good accessibility of the roof is an absolute necessity for periodic maintenance. Fall protection (safety lines, cage ladders, ladder anchoring points, roof hatches,…) and walkways covered with rubber granulate mats must be provided, where appropriate, to ensure adequate protection of people and of the building.
  • Roofs covered with gravel ballast and tiles require regular maintenance:
    – Gravel ballast is a support which is sensitive to plant growth.
    – Dirt may accumulate between the tiles and the roof sealing
    The space between the roofing and the tiles must be cleaned on a regular basis.
  • Vegetation-covered roofs are subject to periodic garden maintenance. During the green roof maintenance, the roofing system and safety provisions must be checked at the same time.
  • Accumulation of dirt on white reflective roofs can adversely affect their reflective properties, hence treatment with IKO pro maintenance products is recommended.

Reporting of the works carried out

A key aspect of the roof maintenance is the reporting on the works carried out.
This report ideally includes the following data:

  • date of execution of the maintenance
  • summary of the defects and faults detected relating to
    – improper use of the roof sealing
    – damage caused by activities of other construction professionals (such as chimney sweeping, lift maintenance, rubbish chute, mechanical ventilation,…)
    – visible defects in the rough structure which can have an impact on the waterproofing
    – defects requiring renovation
    – damage caused by corrosion
    – weaknesses or defects in the waterproofing
    – presence of objects that the technician could not remove himself
  • recommendations relating to the execution of certain works which are not covered by the maintenance or the contractor’s ten-year liability


  • It is recommended that the report includes photographs taken before, after and during the maintenance.
    Those photographs illustrate:
    – the entire roof surface (before/after)
    – areas that need to be renovated or repaired, clearly identifying and describing them
    – objects that are present on the roof
  • The work order, signed by the client, for the maintenance carried out is essential as it allows the contractor of the maintenance work to demonstrate that he informed the client of certain recommendations.

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This IKO White Paper is part of a series of IKO White Papers. With these documents IKO aims to highlight the various technical aspects of flat roofs that are important to Architects and Roofers. As a manufacturer of both waterproofing and insulation products, IKO boasts 100 years of expertise in flat roofs, which it is happy to share with you.

These documents are not just a list of useful tips. Above all, they seek to defend a pragmatic quality philosophy with attention to detail which will benefit clients and roof professionals alike.

Indeed, with our slogan ‘IKO, Setting the Standard’, our aim is to set the standard in our field.
Combine all of our White Papers into a book which you will consult for many years to come. Collect them all.

If you have any further questions or comments, contact us via info.be@iko.com

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