How to repaint heavily rusted metal side wall claddings?

RD-Elastometal, a very high performance elastomeric coating combining superior anticorrosion and sealing properties,

RD-Metal unicoat, the ideal solution to give a new aspect to your cladding while protecting them from corrosion. Available in a wide choice of colors to match the visual identity of your business.

The problem

The coating layer of metal claddings protecting the walls are subject to bad weather and different climates that can be very aggressive at the seaside or in very polluted industrial areas. The rays of the sun, the rain, the wind carrying chlorides, atmospheric pollution coming sometimes directly from the neighboring factory, attack these surfaces on a daily basis.

The coating begins to change appearance after several years and sometimes quite quickly depending on the orientation of the building. The color changes or becomes chalky and whitish, rust appears - first on the edges and around bolts and fasteners; the original coating, may also begin to peel or disappear, leaving the metal side walls bare, exposed and unprotected.

Once the metal is exposed, even if previously galvanized, the work of oxidation and rust begins. Usually, if the metal is galvanized, there will first be whitish traces of zinc salts.

Then, the harsher the environment and the more exposed the surface is, the faster rust will appear and will quickly spread over the entire surface. There are ways to stop these degradations and fix them in the long term.

RD Coatings offers eco-responsible and easy-to-apply solutions that will effectively and durably protect your building!

The solution

RD-Elastometal & RD-Metal Unicoat

To stop the action of rust and renovate the metal cladding, it is necessary to use a combination of RD-Elastometal as a first coat and RD-Metal Unicoat for the second coat. The first coat of RD-Elastometal will provide excellent corrosion protection. It adheres perfectly to metal or weathered galvanized surfaces (> 1 year old) and thanks to its permanent elasticity, it will follow the expansion and retraction movements resulting from permanent changes in surface temperature.

The second layer, will be with RD-Metal Unicoat, a simple, fast and economic solution giving a neat aesthetical finish to obtain a successful relooking of the building.

Both products have good anticorrosive properties, are UV resistant and weather resistant. They are one-component and water-based and therefore do not present any danger or fire risk. They are also suitable for application inside occupied buildings and will not affect occupants.

They are available in a wide choice of colors from as little as one liter!

Recommended quantity and thickness

RD-Elastometal: 0.4 Kg / m² for 175 µ sec - 130 p² / gallon for 14 mils sec.

RD-Metal Unicoat: 0.20 L / m² for 95 µ sec - 200 p² / gallon for 3.8 mils sec.

The total thickness obtained will be +/- 270 µ / 10.8 mils sec.

Our products being water-based, you avoid

  • bringing hazardous products to the job site and at the same time you eliminate the risk of fire or explosion;
  • nuisance in the vicinity with disturbing odors during and after application;
  • emissions of harmful substances;

You respect nature, the applicator and your immediate environment.

Benefits and expected performance of the system

The system will have a long life if applied correctly and according to our recommendations.

The service life of the system is generally more than 15 years! Many projects can benefit from the RD Coatings warranty. See the "RD Coatings Warranty" page for details.

One of the great advantages of the product is its ease of use. If there are touch-ups to be done several years later, the use of RD Coatings solutions makes it possible to carry out occasional repairs very easily and in record time!

It offers many advantages to all the stakeholders:

For the project manager/owner

  • No blasting required, economical solution
  • High performance and durable system
  • Eco-friendly
  • Water based, safe, no fire hazards
  • Virtually odorless, can be used in occupied buildings without disturbing
  • Wide choice of colors
  • Limited downtime, possible to apply within 24 hours

For the applicator

  • Easy application
  • Almost no VOC
  • No isocyanates
  • High performance
  • Proven track record
  • No pot-life
  • One-component and quick-drying
  • No need for solvents nor thinners.

Getting ready


Like any outdoor project, try to avoid starting a job in rainy weather. A minimum of 10 ° C / 50 ° F and no rain forecast during and immediately after application are required to apply the products.From 15 ° C / 59 ° F, working conditions are comfortable and allow higher productivity.

If the project is located in a very hot area with very intense sunshine during the day, you should avoid applying the system when the sun is the most intense and prefer working early in the morning or late afternoon.

If you are working in humid climates, and especially if it is cold after sunset such as in the fall or spring, be sure to finish the job a few hours before dark. Otherwise, you may have condensation covering the fresh paint which will prevent it from drying.

If you are working at dawn, beware of condensation on the surface, avoid it!


Avoid carrying out painting works in late autumn or early spring, and of course winter, when the weather conditions are sometimes too uncertain. RD-Elastometal and RD-Metal Unicoat do not have an overlap window. In other words, if the work should be interrupted due to a sudden change in the weather, it can be resumed later without any problem!

Surface preparation

The surface must always be clean, dry, degreased and free from any contaminant. The most convenient and quickest way to do this is to clean the surface using a high pressure washer powered at minimum 180 bar / 2600 psi equipped with a rotating zero degree angle nozzle. This method will remove non-adhering rust and contaminants, as well as existing paint showing lack of adhesion. If the existing paint resists  to the cleaning, it means it has sufficient adhesion and can stay in place.

Cleaning by hand or with a power tool is also an option and is advised when more detailed surface preparation needs to be done near the edges pr on objects such as chimneys, access ladders and bolts that would be heavily rusted.

Moss and mold can be removed with suitable cleaners. Consider using biodegradable solutions that are easy to find and very effective.

Inspect and treat bolts

It is important to inspect the condition of the bolts securing the metal panels to each other and to the wall structure. Defective fasteners and bolts must be repaired or replaced.


Brush a spot coat of RD-Elastometal over each fastener after inspection. This will not only help visualize the progress of the inspection, but also add a protective first layer to those weak spots.

Edges and ridges

Also check the edges and ridges. These are places easily subject to corrosion. Remove all contaminants and apply RD-Elastometal by brush. You will notice that it covers the edges perfectly and will protect them even more.


An additional step, which may depend on the location and the extent of the pollution, would be to use soap and water to degrease the surface and remove any oils, pollutants and grease. Observe the surroundings to see if any chimneys are emitting fumes as they can cause an accumulation of contaminants on the walls.


It is preferable to apply RD-Metal Unicoat and RD-Elastometal with a brush on specific areas and with an airless on main areas. If spraying is not possible, you can also apply the coating by brush. Choose the type of brush according to the size of the objects to be painted.

Specifications for an airless application

RD-Metal Unicoat: 180 bar / 2600 psi outlet and nozzle between 0.013 and 0.015 inches.

RD-Elastometal: minimum output of 180 bar or 2600 psi and a nozzle between 0.015 and 0.019 inches.

Both products can also be applied using the Graco Ultra Max portable airless device. It's a simple and effective method for small jobs or for touch-ups on larger scale projects.

Simply rinse the airless device with clean water when changing the product.

At the end of the job, simply clean your equipment with plain water or according to the equipment manufacturer's manual.

We do not recommend applying by roller as it is difficult to achieve the prescribed thicknesses. If you decide to do this, you will need to apply multiple coats to achieve the recommended thicknesses. We recommend using 14mm polyamide rollers or 3/8 inch nap rollers.

The application

The products are ready to use. Stir them mechanically for a few minutes before application.

RD-Elastometal has a fairly high viscosity, which is normal. Do not add water except when clearly specified. Check before each application that the surface is free of dust, contamination or condensation.

If preparation or application has been interrupted for more than 3 days without rain or if it is located in a polluted environment, we recommend that the areas to be coated be washed again or rinsed with a high pressure cleaner.

The application

If you intend to use a dry film thickness measuring device, measure the thickness of the remaining coating or galvanized steel to later calculate the total applied thickness. If you do not have this device, you can use a wet film gauge during the application that we can provide.

Apply the first coat of RD-Elastometal over the entire surface.

The thickness is important and should be in line with our recommendations. It will be your guarantee for the long term performance of the system.

Allow the paint to dry for 6 hours before recoating. Depending on the weather, it can be shorter or longer.

Apply the second full coat of RD-Metal Unicoat over the entire surface.

Finally, finish details such as metal objects, corners and edges with a paintbrush to make sure they are well covered. After 4 hours of drying at 20 ° C, the coating is dry and resistant to rain.

The products you need