How to paint a fiberglass or composite balcony with epoxy in Quebec

Even if it’s often perceived as less attractive than wood, fiberglass remains a very robust material for building a patio or balcony. This is also why it offers excellent value for money. Plus, a fiberglass balcony generally requires less maintenance than a wooden one.

Maintaining a fiberglass balcony

Since fiberglass is very smooth and resistant, you can’t apply just any floor paint to it. Why? Because ordinary paint doesn’t adhere durably enough to this surface, and eventually peels off at the slightest impact or flakes quickly.

The best option for durably covering a fiberglass balcony is therefore a urethane mastic formula. This type of product settles and hardens on the fiberglass surface. This allows for long-term protection. Especially since urethane mastics are known for their very resistant finish.

The Specifics of an Outdoor Project

Since it’s an outdoor surface, urethane mastic is also more appropriate than epoxy mastic as a finish.

The difference lies in the fact that urethane resists the sun better than epoxy. Epoxy mastic adheres well to fiberglass and offers good resistance, but its surface becomes chalky over time due to UV rays.

In short, for durability and value for money, urethane mastic is an excellent option for a fiberglass patio. What’s more, its application is simpler than many products with comparable resistance.

Clean the surface

First and foremost, your balcony must be very clean to avoid any contamination that could hinder the urethane’s adhesion.

• Use a pressure washer to rinse the fiberglass balcony. In addition to cleaning, the pressure washer creates an abrasive effect that helps dislodge stubborn stains.
• If you don’t have this type of tool, you can use a scrubber brush to scrub the surface.

However, steel-bristle brushes should be avoided, as they can damage the fiberglass. The scrubber brush is still less effective at removing deeply embedded dirt from the surface.

We recommend using a surface preparation product to neutralize contaminants that may have accumulated over time on the balcony, in addition to removing dirt.

• Krud Kutter Degreaser is a very good choice. It helps eliminate grease and contaminants.
• Dilute the cleaner following a 6:1 ratio of water to product. If you have oil stains or very stubborn stains, use Krud Kutter undiluted.
• Wet the fiberglass balcony using a hose.
• Spray the solution onto your fiberglass balcony with a pressure washer. You can also spread it with a roller.
• If you spread it with a roller, then scrub with a nylon brush to thoroughly clean the surface.
• Let the cleaner sit for 3 to 5 minutes.
• Rinse with clear water.

Let your fiberglass balcony dry completely before moving on to the next step.

Sand the fiberglass

Then, once the surface is thoroughly dry, you need to lightly scuff it with 80-grit sandpaper. The goal is to make the fiberglass a little more porous so that the urethane adheres well. This is a surface sanding, much less demanding than sanding wood.

This sanding also serves to remove traces of flaking from the old finish. It’s important that you remove anything that’s flaking, to prevent it from causing the new finish to peel. After that, sweep to remove most of the dust. Then finish with a vacuum cleaner to ensure almost nothing remains on the surface.

Mix urethane sealant

Urethane Mastic 9800 is a two-component product. This means it’s made of a resin base and an activating agent, stored separately. Before applying it, you must mix it to initiate the chemical hardening reaction.

• Before mixing, make sure all your materials are ready and the surface is well prepared.
• The urethane mastic kit includes a gallon of resin that is not completely full, so you can pour in the liter of activator. The mixing can therefore be done directly in the gallon.
• Use a paint mixer
• Once the activator is added to the resin, you have a limited time to apply it before it starts to harden. At 21 degrees Celsius, the application time is approximately 2 to 3 hours. The warmer it is, the faster the product hardens.

The kit covers between 160 and 280 sq ft. If your surface is smaller, you can divide the kit to prepare smaller quantities.

• To do this, transfer both components into an empty graduated plastic container. The ratio to respect is 5:1, meaning 5 parts resin to 1 part activator.
• Don’t forget to scrape the edges thoroughly with a spatula or a stick.

If this ratio is not precisely followed, you risk hardening problems. Too much activator can cause the product to heat up and harden too quickly.

Conversely, not enough activator can cause the urethane to dry very slowly, or not at all. In this case, the only way to remove the sticky product will be with a solvent like xylene.

That’s why if you want to divide your kit for multiple uses, you need to pay close attention to the mixing.

Apply the first coat of urethane sealant

Urethane mastic has the advantage of being quite easy to apply thanks to its more rubbery texture. You can apply it with a bristle brush or a roller.

• Use the brush to cut in the corners of your fiberglass balcony. With the roller, cover the rest of the surface.
• Avoid applying it too thickly. The ideal thickness for one coat is 3 to 5 mils.

For an even more uniform result, you can also apply it with a sprayer. In this case, it is preferable to dilute the product up to a maximum of 10%.

Once the first coat is applied, let it dry for at least 16 hours. It’s even better if you wait until the next day before applying the next coat.

Final step: apply the second coat of urethane sealant

After 24 hours, you can apply the second coat following the same mixing and application method.

Depending on the size of your balcony, there are tricks to reduce product costs. Consult the following table to find out what will be most advantageous for your balcony:

The weather is a detail that cannot be taken lightly in an exterior painting project. It can truly make all the difference between a beautiful result and an unpleasant surprise.

Rain and humidity can cause defects like fish-eye and other problems that harm the epoxy’s finish.

On the other hand, applying the product in direct sunlight or in very hot weather can cause it to harden too quickly. This makes the urethane harder to spread and can even harden before the application is finished.

The best time to apply epoxy to a fiberglass patio is in the morning, once the dew has disappeared and before the sun gets too strong.

Between coats, it’s also better to wait until the next day, even if the surface seems dry after a few hours. This ensures you work in better conditions and get a better result.

By following these steps, your fiberglass patio can maintain its beautiful appearance for several years.

Start your project now!

You will find all the products you need to paint your fiberglass balcony directly on our website.

1. Start by measuring your balcony’s dimensions to know how much product you’ll need. Keep in mind that:
   • The epoxy mastic kit covers between 250 and 500 sq ft
   • Urethane mastic covers between 160 and 280 sq ft per kit.
2. Decide whether to apply 2 coats of urethane or 1 coat of epoxy and 1 coat of urethane.
3. Choose the color you like.
4. Place your order online and choose between in-store pickup and home delivery.

Want to learn more about epoxy? Consult the “Epoxy” section of our blog.