The two most familiar types of flat roof waterproofing are:
'Hot Applied' – 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.
‘Cold Applied’ – 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 System are the only cold−liquid manufacturer offering a solvent−free and odourless alternative, 2K−PUR, which make it particularly suitable for the repair of roofs on schools, hospitals and other occupied buildings.
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.
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 fool-proof way to ensure an adequate thickness of resin,|
|avoiding the vulnerability of other systems to 'thin spots' 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.|
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.
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:
Minimal implied loadings
Warm roof or inverted roof possible
Full design support from Kemper’s technical team
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 System, a large, well−established and reputable multinational company.
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
In much he same way as with project times, it is very difficult to generalise typical project costs as so much depends on local factors. Kemperol is particularly cost effective on complex roofs where there are many details that have to be waterproofed (upstands, penetrations, etc) a process that is comparatively time−efficient with Kemperol (saving labour cost and total installation time) and does not require additional mechanical fittings.
Compared to hot−applied (felt) systems, the difficulty of broad costing is exacerbated because of the variation in the quality of felt systems. For whilst the best of these may offer a warranty of up 20 or more years, some felt systems only have a 15 or even 10 year warranty, reflecting the quality and performance of the materials used. Kemperol has a comprehensive 20 year warranty in addition to any contractor guarantee, and many existing repairs in the UK have now exceeded 30 years performance without failure.
We would recommend you discuss costs with a roofing contractor, as a rule of thumb Kemperol may be more expensive than the cheapest felt systems, but up to 30% lower cost than the most expensive.
Many factors will affect the total roof repair or installation time include the degree of existing substrate repair needed, the complexity of the roof (protrusions, vents, upstands, etc) as well as the total roof area.
Predictably the most reliable estimate of time will come from your appointed contractor following an initial site visit.
However for comparative purposes, one of Kemperol’s great advantages is that it is applied ‘wet on wet’ and so, on a like−for−like basis, can be completed more rapidly and more thoroughly than many cold liquid waterproofing systems. Because optimum wet−out is visible to the contractor (as the fleece becomes visibly impregnated with resin) you can be assured that there will be no, potentially weak, ‘thin spots’ that may occur with other ‘wet on dry’ systems that rely on the use of gauges to test depth of cover.
Traditional Hot−applied systems will typically take longer to lay than Kemperol due to the numerous laminations used in the build up.
As a general rule, the more complex the roof, configuration, upstands, penetrations and plant, the more efficient is the use of Kemperol compared to other systems, with time and cost savings of up to 10% indicated; this increases when there are many penetrations. The reinforcing fleece is simply cut and folded to form a seamless membrane, where (for example) single ply systems require the application of some form of hot welded or mechanical fixing.
Although Kemper System have been established in the UK for over 20 years, our initial presence was through large appointed contractors supplied direct from our manufacturing facilities in Germany. In 1997 Kemper System established a UK Head Office and Distribution Centre in Warrington, with a dedicated staff including distribution, customer support and technical services, and with a national sales operation supporting contractors and specifiers across the UK.
Kemperol is only installed by registered contractors who have completed the Accredited Installer Programme at our Warrington training centre. This ensures optimum choice of product and correct installation across the full range of applications, allowing us to offer a comprehensive product performance warranty in addition to the Contractor's own guarantees. In addition to issuing certificates of competence to registered installers, Kemper System audit the performance and credibility of all approved firms prior to appointment.
Kemper System is the UK arm of IBG Construction Chemicals Group − a multinational waterproofing and coatings business with operations across Europe, North America and the Far East.
Kemperol liquid waterproofing has been used in Europe for over 50 years and in the UK since 1980. In this time many tens of thousands of roofs have been repaired or installed using our systems, on projects ranging from just a few square metres to over 3 million. From large PFI projects in defence, marine and transport infrastructure through to factories, schools and hospitals, the list is very long.
We are proud of the proven longevity of our products once installed. Kemperol's life expectancy accreditation under ETAG 005 is given as 'minimum 25 years' - the highest possible category, however in practice its superior reliability and performance means 30 years and beyond can be comfortably expected. It is now almost 40 years since Kemperol was launched in the UK, and one of the very first projects - the Leicester Mercury building - was installed in the early 1970's and was recently inspected as part of a major refurbishment of the building and reported to be as sound as the day it was installed.
For reference applications similar to the one you may be considering please contact our technical team (01925 445532) or an Approved Contractor.
It is predictable that all materials would point to reasons why they are good (or less bad) for the environment, and in the absence of a total energy equation, incorporating all of the specific factors (and alternatives) available to an individual project, it is only possible to generalise. However, to assist in a broad understanding of why we believe Kemper to be have a lower impact on the environment, we list below the key considerations:
Complete solvent−free systems available
80% Renewable (vegetable) oils used in production of solvent−free Kemperol 2K−PUR resins
20% recycled plastic bottles used in the production of the polyester reinforcement fleece
Lightweight − less structural material needed, lower transport costs to site per m2
Removal of existing substrate (repairs) often not necessary, so no removal (transport and energy) and no landfill (pollution) or specialist disposal (energy / pollution)
No CFC's generated during manufacture, or CO2 released during installation.
No chlorinated carbons used in manufacture
To learn more visit our Environment page.
As well as solvent based formulae, Kemper System are the only leading manufacturer to offer a wet-on-wet solvent free option, Kemperol 2K−PUR, which like Kemperol V210 also has BBA (Agrement) 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 force temporary closure or evacuation. For hospitals, schools and offices this can be a critical consideration, 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.
Kemperol has been widely used in Europe and the UK for over 50 years and so has a strong provenance and proven performance in the most demanding of applications. As part of the Cologne−based IBG Group (a global building chemicals company), we have a highly active and fully resourced research and development programme, ensuring continual improvement and innovation.
Kemperol in the UK is BBA certified, as well as conforming to the quality and product performance standards for various testing and accreditation bodies including:
FM (Factory Mutual)
ASTM (American Society for Testing and Materials),
EOTA (European Organisation for Technical Approvals)
DIN (German Institute for Standardisation).
FLL (Green Roofs)
Bureau Veritas (France) Certification
Yes, there are many applications where Kemperol has been used to repair existing roofs or even for newbuild:
Kemperol is an ideal substitute for lead as a repair material on both falt and pitched roofs: it is far cheaper to install and will bond to the existing lead roof without the need for removal, can be walked on for maintenance traffic and is elastic so withstands thermal movement. It can also be used for newbuild roofs using timber battens to simulate roll joints. Dark and Light grey colours are available for a new or weathered appearance.
Kemperol can be used to repair pitched copper roofs or for newbuild. It can be specified in a Green Patina finish that simulates weathered copper.
In addition to our range of liquid waterproofing, we also supply a wide choice of coatings, including non−slip and skid−resistant options, that are suitable for very hard−wearing applications such as carparks and station platforms. These are available in a selection of standard or bespoke colours, textures and finishes.
We also have a range of floor and wall coatings designed for internal applications in specialist areas such as food and pharmaceuticals manufacture.
For further information on our range of coatings please contact our technical team on 01925 445532
As a member of the RIBA Accredited CPD Provider Network, we can arrange for our seminar on ‘Cold liquid−applied waterproofing’, to be presented at your own offices (minimum 6 delegates), or alternatively you could attend one of the scheduled RIBA CPD Roadshow events that take place throughout the UK.
Product Verification is the process where our own technical team will run through a specification (whether supplied by the contractor or directly with the specifier) and verify that the products selected are appropriate for the nature of the project (substrate, building use, etc.) and also draw your attention to specific details that may need separate consideration, or a different treatment. It is in many ways a very practical 'failsafe' − we are able to use our experience and product knowledge to help ensure that the right products are used and correct practice used when installing.
To verify your project, simply or e−mail your specification or call our technical team to talk through in the first instance. Alternatively, the Project Specifier on our website has a facility to forward the completed schedule online for verification. Whichever method you choose, it's a FREE service made available to ensure your specification is both correct and cost−effective.
When repairing roofs, Kemperol can be applied to the existing substrate without the removalof the original roof covering. So if the insulation is in generally sound condition, then the insulation does 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.
Should you want to upgrade the thermal performance of an existing roof, our Stratex warm roof construction is a complete system comprising primers, vapour barrier, insulation and waterproofing with a range of optional surfacing treatments if required.
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 standard primers. This means that in the majority of cases there is no reason for the substrate on a leaking roof 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. Where existing roof materials are to be covered, it is important to ensure the substrate is sound, free from loose material, clean and dry.
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.
There are several ways in which you can be assured that the correct product has been specified for your particular application:
Firstly, our website has a simple product selector that allows you to quickly identify the product broadly suited to your application. Used in conjunction with the relevant product and application datasheets, elsewhere on the website, allows you to clarify the product features and benefits.
Next, if you have a specific project planned, it may be useful to run our Project Specifier tool (registered users only may access this), a programme that prompts for specific substrate and detailing information. There is provision to forward the resulting specification online to our technical team who will verify product suitability.
Our own Technical Advisors are available to talk through your project and ensure that the right product is selected, as well as offering experienced advice on detailing and other design considerations.
Alternatively, or in conjunction with the above web tools, you may wish to discuss the project with one of our Authorised Contractors − if you need assistance in locating one in your area simply call our technical team on 01925 445532.
Kemper System’s commercial 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. We have 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 System, 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 waterproofing 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.