How Onduline made this low pitch heritage roofing possible

How Onduline made this low pitch heritage roofing possible

Onduline is helping contractors hit the right pitch on a heritage roof

Working on a project within a conservation area generally means adhering to extra planning controls and considerations to protect the historic and architectural elements which make the location special. This was the case for Wigwam Architecture and Build when the company was undertaking an extension development within the historic town of Helmsley.

The company needed a low pitch roofing solution for a small rear extension on a very old property situated directly behind the beautiful ruins of historic Helmsley Castle. The design to complete the build had been approved by planning with stipulations that the roof had to be in-keeping with the local vernacular and to match the existing roof which was fitted with old clay pantiles. As reclaimed pantiles cannot be used on a pitch lower than 25° a sub-roof system to achieve the waterproofing element of this roof was required. 

Stuart Simpson, Senior Project Manager at Wigwam Architecture and Build, said: “As the roof of the extension was at such a shallow pitch compared to the rest of the house, we had to find a solution that would enable us to use the reclaimed pantiles at a 12° pitch. We had previously used a flat roofing product on a project such as this, but this was just not cost effective in this case. Although it wasn’t a large roof there was a lot going on in quite a small area, so we needed to find a different solution for the waterproofing element of the roof. 

“Through our research we came across Onduline’s Isoline Low Line sub-roof system and as it ticked all of the right boxes; significant cost savings that didn’t affect any aesthetics or compromise the build, allowed us to use the tiles at a low pitch, simple and easy to fit, we decided to give it a go. It was the first time that we’ve used the product and the roofers and joiners that installed it learned about the product as we went along. 

“It’s now in-situ and is doing a great job and I would say that there is definitely a market for it. Since completing the project, I have spoken to a lot of people about it within the industry and would recommend it to any contractor looking to undertake a low pitch project.  

“If we have any other projects that require a low pitch sub-roof then this is absolutely what we will use, as it was so simple and stress-free to fit and does exactly what you need it to do.” 

Isoline Low Line is the only system in the UK to be BRE tested and BBA Accredited to as low as 10o with a 30-year guarantee. Designed specifically for use on low pitch roofs, this lightweight bituminous underlay sheeting has been rigorously tested. 

With a corrugation height of just 24mm, Isoline Low Line is fixed below the primary tile or slate roof covering, acting as the primary waterproofing layer of a roof. Thus, making roof tiles a secondary line of defence enabling the pitch of the roof to be much lower than the minimum as recommended by the tile manufacturer. 

Not only does this help to meet the demand for maximising living space, as the low pitch means the roof void can be minimised, it also enables traditional tiles to be used in situations where they wouldn’t have been able to be utilised previously, such as extensions or large roofing projects, greatly enhancing the aesthetic quality of a property. 

Easy to carry, handle and fix, the non-slippery sheets are simple to cut with vertical overlaps embossed into the sheet. This makes installation even quicker and easier as it takes away the need to measure and it also removes confusion when it comes to knowing how much to overlap. 

Due to the corrugations, Isoline Low Line allows increased ventilation and airflow both above and below the sheet and tile battens positioned above the corrugations allow moisture to drain to the eaves which, with the enhanced ventilation, maintains excellent moisture control within the cavity. 

The material is also in line with the growing awareness of ‘green’ issues and the need to offer sustainable solutions as Isoline Low Line sheets are made of a minimum 50% recycled cellulose fibres, contain no asbestos and do not release any hazardous substances.

For more information on the Isoline Low Line roofing system, and Onduline’s other lightweight, eco-friendly and durable roofing solutions visit Onduline Group | Roof suppliers & Roofing manufacturers in more than 120 countries.

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