The most recent dip in the economy that saw a drive for better efficiencies and value for money has also seen a significant increase in the demand for ‘dry fix’ roofing products to reduce or eliminate the requirement for mortar on roofs.
The benefits of dry fix products are well documented and appreciated by most roofing contractors; increasing the speed and reliability of the installation, together with reducing the associated down-time due to inclement weather. They have also been recognised by the NHBC who have identified that the reduction in the use of mortar on roofs will also lead to a reduction in the number of claims that they are required to deal with, together with the cost of these claims.
As the demand for these products has increased, so has the number of manufacturers and importers of these products. Unfortunately this increased demand has also led to an increase in supply of products specifically targeted at the low cost, low specification end of the market. These products are often manufactured using low grade or low quality materials and components resulting in both reduced durability and performance.
Some of these low cost products carry claims from the manufacturers for performance levels that cannot be substantiated and meaningless claims of compliance to inapplicable standards or approvals by bodies such as the NHBC that do not approve proprietary products, together with vague and exaggerated claims for unrealistic guarantee periods.
To address these problems, it is the responsibility of the suppliers and installers of the many proprietary products used with slate and tile roofs to satisfy themselves that the products they are dealing with are fit for purpose and sourced from a reputable manufacturer that has a good reputation for product quality and technical support.
Not all products that appear to be the same are the same. The raw material choices can be anything from the tried and tested to those which are used for cost savings rather than reliable long term performance. Good quality products generally have some form of independent certification to demonstrate their fitness for purpose such as BBA certification and will carry a meaningful guarantee that will be honoured by the manufacturer should a problem of defect arise.
It is now quite common to find that liberties are taken when claiming ventilation areas; products such as tile and slate ventilators may have their ventilation area quoted based on the top surface aperture or grille that is easy to measure, but then might be constructed with an internal geometry or pipe/adaptor spigot that significantly reduces the actual airflow area. Some low cost roof ventilators may even rely on riveted connections in thin weak plastics and foam strips held on with double-sided tapes to achieve the weathering and compensate for poor fit into the roof. Worse still, designs that have proved to have been unreliable in terms of weather protection can now be found to contain coarse plastic foams further restricting air flow and risking blockage by debris accumulating over time.
In recent years, there has also been a dramatic uptake in the use of dry-fix products used for providing a mechanical fix of ridge and hip tiles. Not surprising really with the well documented rise problems experienced when using mortar, but some of these systems claim to provide the requisite roof space ventilation at the ridge when no actual openings into the roof space are provided as required by BS5250:2011 ‘Code of practice for control of condensation in buildings’.
Aside from the consideration of the product design and quality, even the best products available for the job can be fitted either poorly or incorrectly. Reputable manufacturers generally provide good clear and concise instructions on the use of their products for specific applications, or where different techniques are required where a product may be designed for universal application for example. These instructions should be consulted and followed wherever possible; failure to do so could not only invalidate the manufacturer’s warranty, but could, as seen recently, result in a successful claim against the installer of the product.
To address calls from customers and bodies such as the NHBC and the National Federation of Roofing Contractors (NFRC), British Standards are now expected to publish a brand new Standard for dry fix roofing products covering dry fix ridge, hip verge products in the not too distant future.
- Don’t choose the cheapest products available, they are usually cheap for good reason, may take longer to install and might not be entirely fit for purpose
- Use products from a reputable manufacturer of some standing in the industry with a reliable back-up service
- Check the product guarantees and read the small print; they may not actually be of any value
- Ensure that works are adequately supervised by competent persons to ensure good standards of workmanship
- Follow the instructions provided and seek guidance in case of doubt
- Use all of the components supplied with the systems wherever appropriate – they are there for good reason