French heat-reflecting paint firm in financial difficulty

Cool Roof, an innovative Breton firm which promised to maximise the thermal efficiency of buildings with reflective paint, has entered administration while efforts are under way to secure a new investor.

The company uses waste oyster shells in the production of its paint, which reflects 90% of the sun’s rays, compared with 70% for standard white paint.

The outer part of the shell – which is composed of calcium – replaces the calcium traditionally used in paint, maximising its performance and making it more durable.

Cool Roof attributed its difficulties to the wet spring and summer of 2024, which delayed construction work, and to a “brutal” decline in orders in 2025 as new building projects were postponed or cancelled.

Further problems arose from changes to the CSRD and CS3D building and financial reporting standards, which it said had thrown the whole sector of low-carbon building innovation into confusion.

It has seen a 70% decline in its market over the period 2024-2025 and is forecasting a drop in turnover from €15million to €2.5million.

Its predicament prompted Finistère Socialist MP Mélanie Thomin to address parliament in late January demanding that the government take concrete measures to better support companies in the ecological transition sector. 

Cool Roof’s tests show that coating a building’s roof with its oyster shell paint can lower summer temperatures by 8C and cut air-conditioning costs by 40%.

In New York, homeowners with flat roofs have been encouraged to paint them white since 2009, but there is no similar initiative in France.

Flagship projects for Cool Roof have included the roof of Terminal 2G at Charles de Gaulle Airport and two hypermarkets, one near Valence (Drôme) and another in Quimper (Finistère).

Cool Roof, which is confident it will find a new investor, also developed software which uses commercial satellite images to identify hot spots on roofs, and roofs in need of new insulation.