Cool roof for sports facilities

A sports facility combines three handicaps: a very large roof area, a big volume to treat and a dark covering, metal or bituminous. That surface absorbs almost all the solar radiation, heats up strongly in midsummer, then radiates its heat back inside. North-light roofs and roof lights add direct gain. Most sports halls have no air conditioning, so nothing offsets that input. Heat builds up hour after hour and the volume stays hot late into the evening.

Someone exercising produces heat of their own. They therefore tolerate a hot environment far less well than a seated person. Beyond a certain threshold, coaches have to lower the intensity, add breaks, cut the session short or cancel it. French labour law sets no maximum temperature, but it requires the employer to protect staff from heat: coaches, lifeguards and maintenance teams are all concerned. Treating the roof acts on the cause rather than on the timetable.

A reflective roof sends solar radiation back instead of storing it, then quickly releases the little heat it absorbs. Covalba coatings reflect up to 94% of solar radiation. Public laboratories in the United States have documented this passive cooling for decades, and ADEME, the French environment agency, takes it up in its work on urban heat islands. A town-centre sports hall, with its large dark roof, feeds that heat island.

Two families dominate. Steel deck covers most halls and complexes built since the 1970s: it heats up fast and corrodes at the fixings. CovaMetal 20 combines corrosion protection and reflectivity there. Bituminous membrane covers the flat roofs of pools and more recent halls, and four out of five Covalba projects are on membranes over ten years old. When the waterproofing is tired, CovaSeal 20 takes it over and makes the roof reflective at the same time. Our steel deck and bitumen membrane pages cover each case.

For a local authority, the Fonds Vert (French green fund) includes an energy retrofit strand for public buildings that covers summer comfort. A contract under €100,000 is also awarded without a public tender. These two levers clearly shorten the decision cycle on a sports hall, and our public sector page covers them in detail. For a private commercial venue, the CEE premium under the BAT-EN-112 sheet funds part of the operation, provided the funder commits before the quote is signed.

Cool roof is applied in dry weather on a clean substrate, which leaves a wide window from spring to autumn. Nothing happens inside, so the facility does not have to close: scheduling simply follows the quieter periods, school holidays or the clubs’ off-season. The works take from a few days to a few weeks depending on the surface. At €20 to €25/m² supplied and applied, the cost stays far below a new membrane at €80 to €100/m² and pushes the replacement of the covering back by 8 to 10 years.