Blackberry Kilns, Kent

Why Permavent was chosen

Permavent’s patented Plain Easy low‑pitch roofing system was chosen as the only solution capable of enabling handmade clay plain tiles to be installed far below their standard minimum pitch. With planning constraints requiring pitches as low as 17.5°, the system offered the necessary low‑pitch performance while maintaining full watertightness, something traditional handmade tiles alone could not achieve. Its compliance with BS5534, combined with secondary waterproofing, dry battens, improved condensation control, and a 40‑year waterproofing guarantee when installed to specification, provided the design and contractor teams with full technical assurance. Permavent also delivered project‑specific specification support, working closely with both the architect and roofing contractor to optimise tile layout, detailing, and integration with the underlay system. Crucially, Plain Easy preserved the intended handcrafted clay aesthetic at the required pitch, enabling the architectural vision to be realised without compromising long‑term performance.

How Permavent was installed

The successful delivery of Blackberry Kilns’ low‑pitch roof centred on the precise installation of Permavent Plain Easy, which made it possible to use handmade clay plain tiles at a pitch far below their normal performance limits. The roofing contractor installed the Plain Easy trays across the entire low‑pitch area, creating a continuous secondary waterproofing layer that directs water safely down the roof even under wind‑driven rain conditions. Each tray was fixed in accordance with Permavent’s low‑pitch specification, ensuring correct overlaps, alignment, and integration with the underlay.
Once the Plain Easy system was in place, handmade tiles were installed directly over it, allowing the roof to achieve the desired crafted appearance while relying on the engineered trays for watertightness. This approach enabled full compliance with BS5534 despite the significantly reduced pitch. Permavent’s Technical Team provided on‑site guidance throughout, helping the contractor fine‑tune detailing at junctions, raking cuts, and complex interfaces—particularly where the tiled roof met zinc-clad sections.

Quality assurance was maintained through regular inspections, photographic checks, and strict adherence to manufacturer instructions, ensuring the Plain Easy system performed exactly as designed. The result is a robust, watertight, and visually authentic roof that retains the aesthetic of handmade tiles while benefiting from advanced low‑pitch engineering.