Cool roof in Luxembourg: reflective roofs from Kirchberg to Belval and Bettembourg

Cool roofs in Luxembourg: why now

The Grand Duchy has a semi-continental climate: cold winters, summers moderate on average, and only a few days a year above 30 °C. The average hides the essential. Since 2018, heatwaves have been more frequent and more intense; in July 2019, the thermometer came close to 40 °C, and the summer of 2022 brought one episode after another. These peaks hit buildings designed for a temperate climate, often without air conditioning or with installations sized to the bare minimum, in a highly mineralised capital, between the Alzette valley and the Kirchberg plateau.

The problem is not limited to heatwave days. A roof reacts to solar radiation, not to the air temperature: on a sunny June day at 25 °C, a dark steel deck or a bitumen membrane already exceeds 60 °C, and reaches 50 to 70 °C at the height of summer. That heat radiates under the roof covering, onto workstations and loading bays, increases the load on refrigeration units and air conditioning, and wears out the waterproofing with every cycle. Cool roofing acts at the source by reflecting the radiation before it heats the building.

From Kirchberg to Belval and Bettembourg

The building stock concerned fits into a few hubs. In Luxembourg City, the Kirchberg plateau and the Cloche d’Or line up flat-roofed office buildings, shopping centres and public facilities; the station district and Hollerich complete the capital’s office stock. To the south, Bettembourg and Dudelange host the intermodal terminal and its logistics platforms, while Esch-sur-Alzette and Belval have converted a former steelworks site into a university and business district. The business parks of Contern, Windhof, Foetz and Ellange, the freight centre of Findel airport, the river port of Mertert on the Moselle and the data centres established in the south and centre of the country complete the map. Many of these sites work with teams coming from Lorraine, Belgium or Germany, in buildings that must remain usable all summer long.

Local regulations

The French energy-savings certificates (CEE), the French tertiary-sector decree and MaPrimeRénov’ are French schemes: they do not apply in Luxembourg, and none of our Luxembourg proposals mentions them. The Grand Duchy does, however, apply the European directive on the energy performance of buildings (EPBD, directive (EU) 2024/1275) and its energy performance certificate. Switching from a dark roof to a white roof alters the external appearance of the building: this generally requires an authorisation from the municipality, according to its building regulations. We check with the municipal administration before the works and prepare the technical documents, product data sheets and test reports included.

What a PrimaTherm® reflective roof changes

PrimaTherm® is a certified elastomeric coating, applied in four layers: PH169 primer, PH107 reflective base coat in two passes, PH107TCL topcoat. Its values come from test reports attached to every proposal:

On a Luxembourg roof in summer:

• up to −30 °C on the roof surface: from 50–70 °C to 25–35 °C. At the handover of our Marignane project, the infrared measurement of 19 June 2026 read 57.8 °C on the untreated zone against 28.6 °C on the treated zone;
• up to −6 °C felt inside depending on insulation, with an immediate effect under the poorly insulated steel decks of warehouses and workshops;
• up to −40 % air-conditioning consumption depending on the climate zone on the most exposed buildings; under a climate comparable to that of Lorraine, the range we retain is 15 to 25 %, to be refined on your actual consumption;
• waterproofing protected from UV and thermal shock, which matters under a climate that alternates between frost, rain and intense heat.

The Luxembourg winter does not call the balance into question: the low sun strikes the façades, very little the roofs, and the loss of winter solar gain remains marginal compared with the summer savings, as explained in our article on cool roofs in winter. Durability is ensured by the PH107TCL anti-soiling topcoat and by low-pressure cleaning every 12 to 15 months. The system is detailed on the cool roof coating page.

Buildings concerned in Luxembourg

• Offices and commercial buildings of Kirchberg, the Cloche d’Or and Belval, with flat roofs, where air conditioning weighs heavily on the summer bill. See cool roof for offices and flat roofs.
• Logistics and freight: platforms of Bettembourg-Dudelange, warehouses of Contern and Windhof, freight centre of Findel. See cool roof for warehouses and logistics and the steel deck guide.
• Data centres: a sector where every degree gained on the roof eases cooling. See cool roof for data centres.
• Retail and shopping centres of Bertrange, Foetz and the Cloche d’Or. See cool roof for retail and supermarkets.
• Industry: metal, glass and materials processing sites in the south of the country, often in continuous operation. See cool roof for industrial buildings.
• Public buildings, schools and hospitals of the municipalities and the State, where summer comfort is achieved without widespread air conditioning. See cool roof for public buildings.

As for substrates, bitumen or EPDM waterproofing membranes, steel deck account for most cases. PVC is treated only if it is more than ten years old, with a specific adhesion base; fibre cement only if asbestos-free, after a diagnosis.

Our work in Luxembourg

Our head office is in Saint-Laurent-d’Agny, south of Lyon. Luxembourg City is about 560 km away by road via the A6, A31 and A3, i.e. a little under 450 km as the crow flies. At this distance, the project is planned: the technical visit and the works are grouped into a single trip, the team of applicators stays lodged on site until handover, and we group several sites into a single campaign, with Metz, Thionville, Arlon or Liège when the schedules allow. The formalities linked to moving the equipment and the products are handled by Hélios; the quotation is drawn up in euros, with the Luxembourg taxation specified item by item.

Without lifting

Drums and machines stay on the ground; only the hoses go up to the roof. No crane, no road closure, no footprint on your loading bays or car parks, which matters on logistics sites in operation and in dense office districts.

The steps

1. Free study within 48 h: satellite measurement, identification of the substrate, first review of the Luxembourg incentives. Request the study.
2. Technical visit: adhesion test on three zones, survey of singular points (skylights, parapets, drains), schedule taking into account the season and the grouping of sites.
3. Preparation: low-pressure cleaning, repair of waterproofing details if necessary.
4. Application in four layers: PH169 primer, PH107 reflective base coat in two cross passes, PH107TCL topcoat. Application window between 12 and 35 °C on a dry substrate: in Luxembourg, it runs in practice from May to September, setting the schedule on rain-free windows.
5. Check and handover: thickness check, infrared measurement before/after, site monitoring sheet and as-built file.

Polycarbonate skylights receive PrimaTherm® LT lacquer (one coat ≈ −25 % light and heat gain, two coats ≈ −50 %). How we work is described step by step.

The nearest reference

Our Paris-Le Bourget project, less than 400 km from Luxembourg City via the A4 and A31: roofs treated with the PrimaTherm® system in four layers, on an aerospace site in operation, under a prevention plan, without lifting and with a team lodged on site. The largest project remains Marignane: 5,900 m² of bitumen membrane on three buildings, −29 °C measured on the surface on 19 June 2026, site in operation from the first day to the last.

Incentives and regulations

French schemes not applicable. The French energy-savings certificates (CEE), the French tertiary-sector decree, MaPrimeRénov’ and the reduced 10 % VAT on French homes are French schemes: they do not apply in Luxembourg, and we do not include them in any Luxembourg proposal.

EPBD directive. Directive (EU) 2024/1275 requires the renovation of the 16 % worst-performing non-residential buildings by 2030 and of the 26 % worst-performing by 2033, according to thresholds set by each Member State; its transposition is expected by 29 May 2026. A reflective roof does not replace insulation, but it reduces cooling needs and takes its place in a renovation plan.

Luxembourg incentives. The national energy-renovation incentives and the municipal schemes change over time and primarily target insulation and heating systems; during the study we review what may apply to your building, without promising or quantifying anything in advance.

Municipal authorisation. Altering the external appearance of a building generally requires an authorisation from the municipality, according to its building regulations; we check with the municipal administration before the works and prepare the documents.

And the cost? It depends on the area, the substrate, the preparation, the access, the grouping of sites and the incentives; the figure comes with the free study. The cool roof price page explains what makes up the quotation, and the simulator (in French) gives a first order of magnitude of your roof’s thermal potential. Our online shop (in French) delivers to mainland France; for Luxembourg, contact us before ordering.

Around Luxembourg

From the Grand Duchy, the same team covers Lorraine and Wallonia: Metz and Thionville, Nancy, Liège and the Meuse valley, and the whole of Belgium. Find all our service areas.