Organic Roofs and University of Brighton are collaborating on a year-long KEP research partnership to product test and identify obstacles to uptake of our Swiss-inspired lighweight alternative to thin sedum, with support from the Regional Growth Fund (completion July 2016).

Meadow roofs are better for the environment but normally require around 100mm or so (120mm ideal) of substrate and this adds greater costs in materials and structural reinforcement. While these costs are not project killers, they make it easy to value-engineer out biodiverse roofs where no planning conditions require them. Until now.

Introducing HayBase, by Organic Roofs: an established low-embodied energy Swiss method for long-term green roofing applications where high bioversity, longevity, genuinely low install and O&M costings are key project criteria. Turning waste agricultural by-products into construction materials with multiple wins for client, occupant and environment.

HayBase replaces the lower 50% of substrate build up with 75mm or so locally sourced waste agricultural material (hay/straw), overlaid with substrate to comparable depth as a GRO-compliant sedum system, which is then over- seeded (we use local provenance seeds where possible to maximise local relevance).


Project parameters

  • Undertake a consultation with design and procurement stakeholders to identify obstacles to uptake
  • Desk-study to understand policy drivers and collate existing ROI figures in public domain
  • Undertake novel performance evaluation on test rigs and actual sites
  • Coordinate biodiversity research


15 years long-term success on roofs in Swiss roofs monitored by our research partner at ZHAW (Zurich School of Applied Sciences). Multiple existing sites upwards of 5000m2 including schools, office buildings, and public facilities including Basel main tram depot.