How do you apply a heat reflecting coating to a bituminous roofing?

This solution describes the application of a coating to reflect a maximum amount of sunlight to reduce heat accumulation inside a building. It is a solution dedicated to roofs covered with bituminous roofing.

The products you need

The problem

Roofs with bituminous roofing are usually black or very dark. In summer or during periods of strong sunlight, the black colour absorbs the sun's rays and accumulates large amounts of heat which, depending on the insulation of the building, is transferred to the interior.

This results in higher power consumption for buildings with air conditioning units or a stifling feeling for those without. 

Not all paint systems are suitable for application on a roofing.

Good adhesion and elasticity are required to accommodate construction movements and temperature shocks.

A coating is needed that insulates and prevents bituminous substances from seeping through the paint film in the heat, causing brown spots.

The solution

RD-Elastodeck & RD-Roof White

Roofing is done in two quick and easy steps using these two water-based, single component products.

RD-Elastodeck is used as an adhesion primer and insulator, and will prevent bitumen from rising through the film during hot weather.

RD-Roof White is formulated with very high performance white pigments that will last over time. Its elastic film has good resistance to soiling.

These products can be applied to commercial or industrial buildings as well as to a houses.

A technique that improves the performance of photovoltaic panels!

Several studies have shown that a reduction in the surface temperature of a roof covered with photovoltaic panels results in a higher performance.

Recommended quantity and thickness

1 kg / m² for 440 µ dry - 50 p² / gallon for +/- 17 mils dry.

RD-Roof White:
0,5 kg / m² for 180 µ dry - 110 sq. ft / gallon for +/- 7 mils dry.

The total thickness of the system will be +/- 620 µ / 24 mils dry.


This solution is only applicable for sound roofs, without leaks, delamination or other problems. In case of leaks or stagnant water, please refer first to our solution How to restore a flat roof covered with a bituminous roofing? or contact our technical service.

Benefits of the system

This system offers multiple advantages for the contractor and the applicator:

  • low VOC (volatile organic compounds) and CO₂ emissions
  • easy to use solution
  • quick and easy surface preparation
  • fast drying times
  • reduced downtimes
  • long system durability

Our water-based products prevent:

  • bringing hazardous products to the site while eliminating the risk of fire or explosion
  • nuisances in the vicinity with annoying odours during and after application
  • emissions of harmful substances

Getting ready


When working outdoors, avoid starting a job if rain is forecast within 3 hours of application. A minimum of 12°C / 54°F is recommended for comfortable working conditions with higher productivity. Avoid working in direct sunlight, especially in very hot areas, where early morning or late evening work is preferred. Ensure that there is no condensation on the surface before and during application, and during the first hours of drying.

Surface preparation

The most popular and fastest way to achieve good surface preparation is to clean the object with a high pressure washer equipped with a rotating nozzle at a zero degree angle and with a minimum pressure of 200 bar / 2900 psi. This procedure will remove contaminants and possibly adhering paint from the surface. Paint residues that have resisted cleaning may remain as they still have sufficient adhesion. Ensure that the surface is free of moss, mildew, oils, grease and chlorides (salts). Rinse with an alkaline solution (this can sometimes be added to the pressure washer). Do not hesitate to use RD-Eco Power Clean to clean the surface! A powerful biodegradable cleaner.

Check whether the existing coating is still adhering properly. Never paint on a poorly adhering coating!


RD-Elastodeck and RD-Roof White are easy to apply with a roller or airless sprayer. They can also be applied with a brush to hard-to-reach areas.

Roller application is more time consuming than airless application and you may need to apply more coats to achieve the minimum recommended thickness.

The type of brush to use is very common, so use a thick brush suitable for water-based products.

If you are spraying, use an airless with a minimum pressure of 180 bar or 2600 psi and a nozzle varying between 0.017 and 0.023 inches.

If using a roller, we recommend using 14 mm / ½ inch polyamide rollers.

The application

Preparation of RD-Elastodeck and RD-Roof White

The products are ready to use, stir them mechanically for several minutes and if necessary dilute up to 3-5% with water if you are working in very hot weather to delay the drying process slightly.

Applying RD-Elastodeck

The first coat of RD-Elastodeck is usually applied with an airless device or a roller. Application with an airless device allows a quick application of a thick film with a uniform surface and without any traces of rework. RD-Elastodeck produces almost no spray mist. Moreover, it is dry fall.

When applied with a roller, two coats may be required depending on the length of the bristles of the roller used. As the product generally dries very quickly, it does not take long.

Let dry for at least 4 hours (at 20°C - 68°F) before applying the next product.

Application of RD-Roof White

RD-Roof White can also be applied with an airless device or a roller.

When applied with a roller, two coats may be required depending on the length of the roller's bristles. As the product usually dries very quickly, it does not take long.

The system will be dry within +/- 6 hours!

Thanks to the high content of high performance white pigments, the roof will reflect a maximum of sunlight, resulting in better indoor comfort and savings!