Winter's coming: The stark truth about ponding water

Ponding water

Existing flat roofs and gutters are often subjected to standing water, or ponding, especially following heavy rain. The general assumption is that as a waterproofing system is designed to prevent water ingress, standing water will not be an issue. The reality can however be different as the long-term interaction with water ensures that ‘hydrolysis’ becomes a factor.

The simplest definition is that hydrolysis is the decomposition of substances by water into their primary products. If the substance in question is a waterproofing system, clearly this is an issue for the long-term integrity of the waterproofing of the structure. In roofing applications, there are numerous reasons to avoid standing water, ranging from loading to slip hazards, and for inverted applications in particular, the thermal performance of the construction may be affected. Clearly, given the reality of refurbishment, standing water and ponding cannot always be avoided. These applications specifiers and users need to ensure that the selected waterproofing system is fully capable of dealing with any potentially long-term standing water and is hydrolysis-resistant.

Zero pitch

Not with standing the requirements of British Standards, over recent years, the terms ‘zero pitch’ and ‘completely flat’ have been used in the roof waterproofing industry. By its nature, designing a roof to be to zero pitch or completely flat creates an increased risk of standing water, and even with roofs designed to a fall of 1:80 or greater, the likelihood can often be that the ‘as built’ roof construction or parts of the roof may hold water.

If this is the case, the designer needs to ensure that the waterproofing system is suitable and that any guarantee will not be invalidated due to a lack of falls, or the presence of standing water.

Submerged waterproofing

Due to their nature, gutters are continually submerged in water, and this is also the case in non-roofing applications such as water features, fountains, cascades and ponds. The result of this can be significant long-term water loss and a lack of protection to the substrate or underlying structure. Should the need arise to fully waterproof these areas, the waterproofing solution needs a number of specific properties to deal with the extreme conditions, including:

  • The ability to deal with moisture from within the existing substrate
  • High levels of adhesion to the substrate
  • Exceptionally fast rainproof and curing times with ideally single-layer application to minimise down time and risk
  • The ability to seamlessly waterproof complex shapes and details
  • Non-toxic and fully resistant to water treatment chemicals
  • High levels of impact and puncture resistance should the area be trafficked
  • Dynamic crack bridging and suitability for extremes of temperature
  • And of course, exceptional hydrolysis resistance.

The demands of new build applications may be similar, although the structures to be waterproofed may be less robust with higher potential for movement.

Cold liquid applied technology

Seamless, cold liquid applied resins or liquid plastics have proven themselves as problem solvers in the construction industry for more than 40 years and can provide an effective method for waterproofing submerged applications or areas subject to standing water. With many systems demonstrating proven performance in excess of 25 years and millions of square meters already laid, cold liquid applied waterproofing is the solution of choice for the increasingly complex roofing industry.

Liquid applied waterproofing systems not only meet all the required criteria necessary in handling these often difficult waterproofing applications, they also provide a cost effective method of dealing with everything from a completely flat roof to a duck pond.

For more than 30 years, Triflex UK has been a leading European specialist in the manufacture of cold liquid applied waterproofing, surfacing and protection systems. Triflex stands out as an innovator, offering not only a range of extraordinary liquid applied roof waterproofing systems, but also waterproofing and surfacing solutions for car parks, walkways, balconies and terraces.