The two most familiar types of flat roof waterproofing are:
The build up of one or more layers of molten bitumen and roofing felt to create an impervious membrane, sometimes involving the direct use of flamed torches to heat the bitumen to the required temperature. This process gives off noxious bitumen fumes and has an associated fire risk through the use of boilers or torches on the building itself.
This method avoids the use of heat or flames and instead uses specialist ‘cold liquid’ resins to impregnate a fleece-based substrate which then cures to provide a waterproof membrane. Solvent-based systems are rapid-setting but may give off fumes whilst curing.
Kemper are the only cold-liquid manufacturer offering a solvent-free alternative, 2K-PUR, which make it particularly suitable for the repair of roofs on schools, hospitals and other occupied buildings.
Why use cold-applied for repair?
The major advantages of cold applied liquid roofing for flat roof repairs can be summarised as:
- Unlike torch-applied systems, no risk of fire
- A relatively ‘clean’ process
- A proven method - highly durable and reliable
- Minimal additional loading, no structural reinforcement required
- Conforms to EOTA and other international standards, BBA-certified
- No need for evacuation of residents or suspension of production (solvent-free formulations)
- Permeable to water vapour
Why use cold-applied for new-build
There are many benefits to using cold-applied roof waterproofing when designing flat roofs on new buildings, not least the greater freedom of design resulting from:
One of the further advantages of Kemperol waterproofing is the ‘fit and forget’ ethos that is associated with this proven product: it is a highly reliable option that is installed only by trained contractors and which has an exceptionally low rate of recall for snags – a point independently supported by many housebuilder customers who see this as one of the major attractions of this method of build. The product is fully warranted by Kemper – a large, well-established and reputable multinational company.
- minimal implied loadings
- warm roof or inverted roof possible
- full design support from Kemper’s technical team
What are the benefits of cold-applied over other methods
Compared to hot-applied methods (torched bitumen) there are no fire risks or associated insurance, health & safety and operator restrictions. As Kemperol systems are all vapour permeable this allows the building to breathe whilst the solvent-free options enable work to proceed without the need for evacuation or production stoppages.
Kemperol will bond to a great many substrates, allowing its use in many situations without having to remove and dispose of the existing roof covering. This saves time and avoids the cost of removal and cost/environmental issues associated with disposal.
In many cases the Kemperol roof system can be installed or repaired without the need for scaffolding – a further cost saving that also minimises disruption on the site. Finally the superior robustness and durability of cold applied waterproofing compared to other systems makes life cycle costings particularly attractive for those who may have a vested interest in the long term performance of the roof system.
What are the benefits of Kemperol’s ‘Wet on Wet’ application
Compared to other cold- applied liquid waterproofing systems, Kemperol is the only leading brand that is applied ‘wet on wet’. In practice this means the polyester reinforcing fleece is first saturated with Kemperol resin, bonding the membrane to the substrate, with the surface layer then applied onto the bonding coat whilst still wet, so forming a single seamless membrane of uniform thickness.
As a result, Kemperol has all the benefits of a cold-applied system, whilst offering three major advantages over all other cold-applied systems where the basecoat and top layer are separately applied:
there is zero risk of delamination through poor bonding between the layers
full absorption of resin into the fleece is easily visible – a foolproof way to ensure an adequate thickness of resin, avoiding the vulnerability of other systems to ‘thinspots’ when contractors do not use gauging equipment to confirm adequate base layer thickness as recommended.
Considerable time saving: without the need for drying between coats it is feasible to completely waterproof large areas of roof in a single day
What is the ‘solvent-free’ version of Kemperol?
As well as solvent-based formulae Kemper are the only leading manufacturer to offer a solvent-free option, Kemperol 2K-PUR, which like Kemperol V210 also has BBA (Agrément) certification and so may be used for both new-build or repair.
The solvent free formulation is particularly well suited for the refurbishment of occupied buildings, where solvent fumes might require temporary closure or evacuation.
For hospitals, schools and offices this can be critical, whilst for industrial buildings or manufacturing plants the cost benefits of uninterrupted productivity are often more significant than the cost of the roof repair itself.
Concerns for an environmentally responsible approach to all aspects of building or maintenance amongst local authorities and corporations will increasingly favour the use of solvent-free Kemperol.
How well trained are independent contractors
Kemperol waterproofing systems are only available to authorised, registered contractors as part of a strictly maintained quality process to ensure that product installation is always undertaken by fully trained and qualified personnel. Unlike other ‘one size fits all’ solutions, Kemperol has dedicated solutions for specific applications – this is one of the reasons for the exceptional durability and reliability of Kemperol in the most demanding circumstances.
Not only must the Contracting firm be accredited by Kemper, but individual installers have to attend an intensive programme at our Training Centre in Warrington. Attendees, who are all experienced roofing contractors, are then given comprehensive training to familiarise them not only with correct product selection for different applications, but on installation techniques, quality management and safety.
Contractors who successfully complete the course are themselves certificated to install Kemperol systems. This is a rigorous training and verification procedure designed to ensure that Kemperol is installed to the highest standards and safeguarding your confidence in the long-lasting performance of our products.
For repairs, will the old roof need stripping first?
This is not quite a straightforward question to answer, as many factors will affect the decision.
However, Kemperol is a hugely versatile waterproofing material with primers suited to different substrates wherever this might offer a superior bond to the standard primer . This means that in the majority of cases there is no reason why the substrate on a leaking roof has to be removed – Kemperol forms an immensely strong bond and will create a waterproof membrane that is elastic – so will withstand movement – yet is also permeable to vapour, allowing the roof to breathe.
Even previous repairs and damaged substrates may be covered with confidence, for Kemperol will bridge cracks and tears up to 2mm, whilst anything larger can easily be made good on site using a mix of resin and kin-dried sand – your contractor would be able to advise on this, following an initial site visit.
And because Kemperol is a lightweight repair system, it is highly unlikely that the existing supporting structure will need to be strengthened in order to accommodate the additional loading of the Kemperol membrane.
Do I need to upgrade the roof insulation when undertaking a repair?
When repairing roofs, not only can Kemperol often be applied without removing the existing material, if this is in generally sound condition, but in this instance the insulation does then not need to be upgraded to comply with current Building Regulations – as is the case when replacing the original roof material.
This allows building owners the option to either replace or not dependant on local considerations.
Another good reason for choosing Kemper Solutions.
What are the ‘hidden’ benefits of Kemperol
Kemperol cold-liquid waterproofing will typically save time on site compared to other waterproofing systems, which ultimately should be reflected in lower actual costs. But aside from the installation costs, this speedier completion means less disruption (in the case of repair work), whilst with Kemperol solvent-free there will be many applications where costly disruption is avoided altogether, due to there being no need to evacuate the building or suspend production.
This can represent a major cost benefit to manufacturing businesses, warehousing and food preparation, schools, hospitals, offices, hotels indeed any working environment where disruption to operating processes will incur a real cost.