05-08-2011Solar photovoltaics are a major growth area for roofing contractors. The market for solar PV technology has grown by an average 30% per annum in the last 20 years. Largely driven by the UK Feed-In Tariff and legislation such as Carbon Reduction Commitment and Code for Sustainable Homes, lately underpinned by the Renewable Heat Incentive,
In achieving to zero carbon buildings it is widely recognised that solar PV has an important role to play. It is no wonder therefore that specifiers are selecting PV solutions for both new and existing buildings. This trend presents a real market for the savvy installer. Here Phil Singleton looks at the way solar solutions are being adapted for use with waterproofing membranes.
A flexible waterproofing membrane is ideal as a roof covering because it enables the replication of architectural finishing without the price tag. For many roofing contractors it is a tried and tested formula for success. However, to install solar PV as a renewable energy solution there is frequently a compromise to be made and the contractor is faced with a challenge. Penetrating the roof covering and compromising its integrity in order to fix the panels or a mounting system can lead to potential water ingress if a guaranteed integrated waterproofing solution is not incorporated.
However, product development and new technology is enabling solar PV to be combined with the reliability, design and cost benefits of flexible waterproofing membranes. Such developments are enabling the contractor to avoid the time, cost and complication associated with more expensive roofing systems. Instead the architectural specification can be fulfilled using well-known, trusted solutions.
Typically a mounting system is required because it is commonly agreed that solar PV technology works most effectively when it is installed at an angle, with a southerly aspect. Flat roofs present a challenge though, despite their prevalence in the commercial and light industrial sectors - a market particularly favouring solar PV.
The solution can be found in flexible thin film PV membranes, which can be applied directly to a waterproof membrane on a flat roof, or up to a maximum pitch of 40 degrees. These flexible PV modules, such as ICOSUN from Icopal, work by converting daylight into electricity, meaning they will work even on a cloudy day. PV modules that can be bonded to a waterproof membrane are equipped with a self-adhesive underside, so they are quick and simple to install. Because they are delivered to site in light weight rolls, weighing just 7.7kg per roll, there are limited risks for the contractor when working at height. The simple installation technique means the waterproofing membrane can be fully installed in the first instance with the PV modules easily bonded into place as a secondary operation with no need to penetrate the roof covering in order to install a mounting system. This means the installer will not need to work over the top of the PV modules, avoiding potential damage as a result.
There are still instances where a mounting system is the preferred method to apply rigid panel photovoltaic roofing technology. There are now adjustable and adaptable lightweight mounting methods available that do not compromise the integrity of a waterproofing membrane because they incorporate integrated waterproofing details. The benefit of a mounting system is that it provides the choice of having either the PV panels flat to the roof (but not flush to it), or installed at a favourable angle. This therefore may be the preferred installation technique where a sloped panel will operate more effectively that one which is flat to the roof.
Where a mounting system is needed and it is to be installed over a flexible membrane, contractors should look for lightweight systems with an aluminium alloy profile that can be installed with an integrated weathering detail to cover any penetrations, so that watertightness and integrity are not compromised. In fact the ICOSUN Console from Icopal is simple to install. In the longer term it is easy to maintain for the end client too. Such a mechanical fixing is achieved by a lightweight stainless steel plate. This incorporates a factory sealed weathering collar, together with a stainless steel mount. Once in place on the roof the consoles will support any snow load and resist wind uplift without applying stress to the existing roofing membrane. Thermal expansion is accommodated by allowing free movement in the horizontal plane
Whether the architectural specification calls for PV modules that are flat to the roof or rigid panels installed at an angle in order to maximise the amount of sunlight available, there is a solution to help the roofing contractor meet the need. Thanks to legislative drivers, which are pushing the popularity of solar PV as a viable renewable energy source, roofing contractors are likely to face an increasing number of these specifications. Having a solution to meet any need that can be combined with tried and trusted roofing methods will enable the speedy, simple and cost effective completion of any solar PV project.
For more information on Icopal’s solar PV photovoltaic roofing solutions.