How to Paint uPVC Trim, Doors & Window Frames

Painting your windows can be a relatively cost-effective way of freshening up your home! Check out our guide below to learn how to give PVC, uPVC or Aluclad Windows & Doors a new look!

Why Paint Your Exterior Trim?

Refreshing your home's exterior trim is one of the simplest ways to enhance kerb appeal and protect surfaces — without the cost of full replacements. Many exterior elements, such as window frames, doors, fascias and soffits, are made from durable materials like PVC, uPVC or Aluclad. While these are built to withstand the elements, years of exposure to sunlight, moisture, and general weathering can cause fading, discolouration, or staining.

Can You Paint uPVC?

Yes — you absolutely can paint uPVC, and with the right products and preparation, you can achieve a durable, attractive finish that lasts for years. uPVC (unplasticised polyvinyl chloride) is widely used in exterior elements like window frames, doors, and trim because it’s strong, low-maintenance, and weather-resistant. However, over time, the original finish can become faded, patchy, or simply look dated.

There’s a common misconception that uPVC can’t be painted, largely because the surface is non-porous and was originally designed to be maintenance-free. But thanks to modern advances in paint and primer technology, it’s now perfectly possible to paint uPVC — as long as you follow the correct steps.

The key to success lies in surface preparation and using the right type of primer and paint. uPVC doesn’t naturally allow paint to stick well, so the use of a good-quality primer is essential to ensure proper adhesion and a long-lasting result. 

That said, painting isn’t always recommended for brand-new uPVC, as the surface oils from manufacturing can interfere with adhesion. It’s generally best to wait at least six months before painting new installations.

Tools for the Job: Painting uPVC, PVC, or Aluclad

• ✔ Deltec Gold 36mm Masking Tape
• ✔ Microfibre cloth
• ✔ Fluxaf Pro Clean
• ✔ Fine Grade Sandpaper (320 grit)
• ✔ Ralston Aqua All-Primer tinted to the colour of your choice
• ✔ Ralston Aqua Semi-Mat / Satin / High Gloss tinted to the colour of your choice
• ✔ Van Dam Brush
• ✔ Dust Sheets

Step 1: Clean Thoroughly

As with any painting project, proper preparation is essential — and it's the most common step people rush or overlook. Skipping prep might save time at first, but it's the most common cause of paint that doesn’t last.

Begin by choosing a warm, dry day to carry out the work. Adequate drying time is vital, especially when dealing with smooth, non-porous surfaces like uPVC.

Start by wiping down the surface with a dry cloth to remove loose dirt and dust. It's important that the surface is completely clean before you prime or paint — especially if you're not planning to sand it beforehand.

Next, clean and degrease the surface thoroughly using a suitable cleaner. We recommend Fluxaf Pro Clean, a powerful concentrated solution that can be diluted for everyday surface prep. Make sure to get into the corners and crevices — missed areas can lead to patchy results or peeling later on.

Once cleaned, go over the surface again with a fresh damp cloth to remove any leftover residue, then allow it to dry fully before moving on.

Step 2: Protect Your Surroundings

Before you begin painting, protect your work area by laying down dust sheets. Mask off any glass or adjacent surfaces using a high-quality, low-residue masking tape. For sharp, clean lines with no adhesive left behind, we recommend Deltec Gold 36mm Masking Tape.

Step 3: Prime

Priming is a crucial step that helps your paint bond properly to uPVC and ensures a longer-lasting, more even finish. Skipping it may save time in the short term, but it will likely lead to peeling, patchiness, or poor durability down the line.

Use a good-quality brush for best results on window frames and other detailed areas. We recommend Van Dam Brushes, which feature a pointed head ideal for getting into tight corners and along edges. Whichever brush you use, avoid overloading it with primer — this helps prevent drips or runs. Keep a damp cloth nearby to catch any stray drips as you go.

Apply a single, even coat of primer to all surfaces you plan to paint. We like Ralston Aqua All-Primer, which offers excellent adhesion and can be tinted to match or complement your topcoat colour. While the finish after priming might look good, don’t be tempted to skip the topcoat — it’s the final layer that provides protection from UV rays, weathering, and everyday wear.

Always stir the primer thoroughly for at least a minute before use to ensure even colour and consistency.

A common mistake is applying a topcoat or second coat before the previous layer is fully dry. Many primers will feel touch-dry quite quickly, but this doesn’t mean they’re ready to be overcoated. Always follow the manufacturer’s recommended drying and curing times — rushing this stage can compromise the final finish.

Pro Tip: Lightly sand between coats using a fine-grade sandpaper (e.g. 240 grit) for a smoother finish and better adhesion. Be sure to remove all sanding dust before applying the next coat — a tack cloth or vacuum with a soft brush attachment works well.

Step 4: Paint

Once your primer has fully dried, it’s time to apply your topcoat. We recommend using Ralston Aqua topcoat, a high-performance, water-based paint that’s ideal for exterior uPVC. For best results, apply two thin coats, allowing the recommended drying time between each layer.

Ralston Aqua is available in a range of finishes to suit your taste and the style of your home:

• Semi-Matt (Eggshell) – soft sheen, ideal for subtle elegance
• Satin – a popular choice for modern trims
• Gloss – high-shine and highly durable, perfect for a traditional finish

Use the same technique as when priming: avoid overloading the brush, work in smooth strokes, and check for drips as you go. You may find it helpful to lightly sand and wipe down between coats for the best finish, especially if you notice any texture or unevenness after the first coat.

While the paint will become touch-dry within a few hours, full curing takes several days. During this time, avoid slamming windows or doors, and try to minimise contact with the painted surface.

Pro Tip: Open your windows for a few hours each day while the paint cures. This helps with ventilation and allows moisture to escape, speeding up the curing process and reducing the risk of surface tackiness.