Protected Open Ridge

Introducing our new natural light ridge system

Protected open ridge systems provide effective building ventilation by allowing efficient outflow of air, whilst reducing draughts.

Our latest innovation is the introduction of a polycarbonate soffit strip to our protected open ridge design, which replaces the fibre cement strip usually found in a traditional protected open ridge system. This unique design lets more natural light into your building and avoids ‘hot spots’ which can be caused by low level GRPs.

This pioneering design allows more light into the building, but channels it through the centre, avoiding livestock.

Book a building assessment with a ME agricultural building specialist >

Removing the cost of poor ventilation

Dark and poorly ventilated buildings can cost your business thousands of pounds through animal health problems and slower growth rates, but it’s the bill you never see. Poorly ventilated livestock buildings can lead to condensation as well as high levels of bacteria and draughts, all of which can have a real impact on animal health and performance. And furthermore, the use of low level GRPs in buildings can lead to ‘hot spots’, resulting in heat stress and a further impact on animal health and performance.

Here at Marley we have been supplying British farmers with roofing and ventilation systems for more than 100 years, and we can help you make the right choices to design a building that works for you.

Fitting protected open ridge systems

The critical factor to efficient open ridge ventilation is the air gap (marked y on the diagram). The clear width of this air gap relates to the number of animals that will be kept inside the building. We recommend professional advice is sought during construction in order to establish the optimum air space required.

To meet the requirements of HSG 33, the gap between the purlins at the apex of the roof should be no more than 300mm. For this reason we show two purlins on each side of the apex. The ventilation gap (y) is therefore limited to 200mm.

In a protected open ridge system the ridge unit is bridged at 750mm centres by galvanised metal straps manufactured to suit the pitch of the roof. The straps are fixed at an angle of 5° from the horizontal. The 6mm polycarbonate is then bolted to the straps along the length of the ridge to form a cover. This cover must be positioned 20mm minimum below the top of the upstands of the ridge units, and the total gap between the cover and the open ridge (x) is such that:  

Here at Marley Eternit, we are always on hand to offer practical and experienced support. Select an option below or call us on 01283 722588.