Marley answers your pitched roofing queries

Marley answers your pitched roofing queries

Marley’s technical team answers some of the common pitched roofing queries from contractors.

Advice from underlays and ventilation, to installing the increasingly popular solar PV solutions, here’s five of the most common technical queries from the past few months:

  1. What does a full roof system include?

A full roof system should include your roof covering, e.g. tiles or slates, in addition to battens, underlay, fixings, dry fix and ventilation. Our full roof system also comes with integrated solar PV and fire barrier as an option. Sourcing a full roof system from one manufacturer offers several benefits, including guaranteed quality and compatibility, compliance with British Standards, technical support and ours also offers a 15-year roof system warranty.

  1. How much power do your solar panels provide?

With the growth in demand for renewables, many roofing contractors are looking to expand their offer to include PV installation. That is why we have just launched a new integrated solar panel. The enhanced Marley SolarTile is quick to install, and the increased efficiency allows for an install time of just 45 minutes per kWp.

The innovative technology gives the benefit of an increase in total power output from the roof area or achieving the same output using fewer panels. A higher power rating makes roof-integrated solar a more cost-effective option, with fewer panels and roofing kits needed to reach the required energy target.

  1. Can you provide an estimate for solar PV?

Our solar configurator, which can be found on our website, helps you to build a solar array, making pricing jobs and calculating panel performance simple. It also includes an energy calculator tool, which will help demonstrate to customers how much they can expect to save on their energy bills by installing solar.

For more information on the Marley Solar Configurator visit

  1. What type of underlay should I use?

There are several design-related considerations including whether it is a warm or cold roof, type of roofing product, how well sealed the ceiling is, size of roof and what wind zone it is in.

There are two main types of roofing underlays: high resistance (non-breathable underlays) and low resistance (breathable or vapour permeable membranes).

For many years, traditional roof constructions have used non-breathable underlays in conjunction with low level (eaves) and high level (ridge) ventilation systems. This traditional approach is both effective and proven.

Newer, breathable membranes come in two different types: vapour permeable and vapour and air permeable. Breathable underlays are generally more expensive than their non-breathable counterparts. However, they offer several other benefits in that they’re lightweight, durable and easy to install, and provide some supplementary advantages when it comes to roof ventilation.

However, don’t rely on a breathable (LR) underlay as the sole means of ventilation. BS 5250 continues to recommend ventilation of the loft space and sometimes the batten space, and so our recommendation is that roofs will always require some form of supplementary low, high or both, levels of ventilation, regardless of what underlay is used.

  1. What is the best way to provide roof ventilation?

Despite misconceptions, breathable underlays should not be solely relied upon when installing clay and concrete roof tiles and additional roof ventilation is also recommended. This can be achieved using eaves ventilation, ventilated dry ridge systems, ridge vents or multiple tile vents to provide the recommended minimum ventilation in accordance with BS 5250. Ensure you are following the new version of this Standard, which was launched at the end of July. See our latest blog for more details

For further information on Marley visit

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