IKO bio solar solutions – Department for Education (DfE)

The Department for Education (DfE) is introducing green roofs and solar panels in its new Net Carbon Zero schools program. Our PV mounting system, using the EGR SolarNature, is integrated into the green roof to ensure a sustainable green roof ecosystem underneath while ballasting against wind uplift.

The waterproofing system is designed with either the IKO Permatec hot melt inverted roof waterproofing system or the IKO BUR felt warm roof solution, alongside either the IKO enertherm XPS insulation or the IKO enertherm PIR insulation. This is all part of built-up green roof system with photovoltaic panels installed above.

Watt Energy Saver have been working closely with the DfE, alongside IKO and EGR, to develop solar solutions that align with the DfE’s specifications, and they have completed a number of projects successfully. The team uses advanced 3D modelling to maximise roof efficiency and reduce the need for additional structures, such as canopies.

Early engagement within the IKO, EGR, and Watt Energy Saver collaborative partnership at Stage 2 is crucial for comprehensive space planning, potential roof yield/carbon savings, confirming grid connection availability, and early cost certainty.

The DfE aims to create environmentally responsible and future-ready educational infrastructure, using a turnkey solution backed by robust guarantees provided by IKO and their partners.

Green roof experts:

Eco Green Roofs

Roof experts:


Solar PV experts:

Watt Energy Saver

Recent projects

IKO Permatec hot melt has been selected by SIG D&T on a number of DfE new build schools for one of their key main contractor supply chain partners. SIG D&T were tasked with providing a robust waterproofing system in-line with DfE requirements for the latest Net Zero Carbon schools.

This led them to specify our IKO Permatec hot melt inverted roof waterproofing system, applied to a IKO Permascreed mastic asphalt screed. The system included IKO enertherm XPS insulation (to achieve a U-value of 0.12), an IKO WCL (water control layer) and a built-up green roof with photovoltaic panels.

The IKO Permatec hot melt waterproofing systems are among the most robust available; BBA certified as having a service life equal to the roof in which it is incorporated. It is also BBA certified to be used with green roofs, and, along with BROOFT4 fire test compliance, is the natural first choice for the waterproofing element.

Permascreed has a considerable benefit over other screeds, such as sand and cement, in that it is manufactured from selected bitumen, limestone filler and specially graded aggregates.

It is similar to that of mastic asphalt waterproofing, meaning that once the Permascreed has been installed, it can resist water ingress, is fully compatible with the Permatec waterproofing system, and can be waterproofed over once cool. The latter means that the duration between laying the screed and installing the waterproofing can be as little as a couple of hours, rather than days.

Both Permascreed and Permatec are manufactured in the UK, which not only supports our national manufacturing industry, but also reduces the carbon footprint of the system compared to products manufactured overseas.

Permatec is the only hot melt system to have an integral anti-root property as part of the waterproofing itself (other hot melt systems need to include an anti-root membrane above the waterproofing layer).

It also has a melting wrapper to each Permatec block, which is included in the hot melt boiler as part of the heating process, so the wrappers do not need to be discarded as waste. This, backed by the IKO Single Point Guarantee, means that there are huge benefits to both the main contractor and the DfE for this waterproofing system.

The system utilises the already-planned-for green roof build-up to ballast the PVs and does so in a manner that allows enough light around the PVs, and, crucially, enough water to track back under the PV to aid plant growth. Both EGR and Watt Energy Saver worked from an early stage collaboratively to deliver these schemes in partnership. With SIG D&T or IKO, you have the option to use our expertise for your next DfE roof.


Maintaining a balanced plant community on the roof is crucial for a sustainable system in the long-term. To achieve this, basic maintenance is required.

We suggest performing living roof maintenance twice to four times a year, mainly in spring and late autumn, or as needed. Keep an eye on the effect of leaf litter on the vegetation as it may affect the plant life, even if it’s beneficial to biodiversity.

Failure to maintain may result in guarantee invalidation. Please note that living roof areas that have specially designed plants should be disturbed as little as possible to avoid harm to microhabitats that may have developed on the roof.


Discover all the benefits of working with IKO and get in touch with your dedicated Area Business Manager today.

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