Priming your MDF skirting boards is an essential step to achieve a smooth, durable and professional finish. Painting directly onto MDF is not recommended. The paint reacts with the material, causing it to become rough and uneven. MDF's porous core absorbs excessive paint, leading to poor coverage, especially around the moulding. Moreover, painting directly traps loose fibres, resulting in an uneven finish.
For this project, we’ll be using Dulux Trade Quick Dry Wood Primer Undercoat, a trusted product known for its quick-drying properties and excellent coverage. It’s easy to use and widely available, making it a great choice for DIYers looking to get the job done efficiently.
Let’s dive into the step-by-step process of priming your skirting boards. While this guide focuses on skirting boards, the same techniques can be applied to other MDF mouldings, like architraves and dado rails.
Tools required
Before starting, you’ll need the following tools to hand:
- Roller brush and tray
- An inch-and-a-half flat brush
- A screwdriver
- A stir stick
- Sandpaper
- Masking tape
Priming skirting boards and architrave
Step 1: Preparing to prime your boards
Before priming your skirting boards, decide whether to prime them before or after fitting. Priming them beforehand is often more comfortable as you can work at hip height instead of on your hands and knees. However, this requires sufficient space and an appropriate surface, such as a table or bench. If working at home, consider using a dining table or garden table, ensuring it’s covered for protection.
Step 2: Setting up your workspace
Lay out your skirting or architrave on a flat surface. Ensure the boards are free from dust or debris by giving them a quick brush-over before starting.
Step 3: Preparing the primer
Open the primer tin with a screwdriver and stir it thoroughly with a stirring stick, ensuring you mix from the bottom. Pour the primer into a paint tray and coat your roller brush completely, ensuring it’s soaked through.
Step 4: Priming the skirting boards
Set the skirting board so the top edge is accessible. Apply a thin layer of primer evenly across the top edge.
Use the roller brush to quickly and evenly coat the flat section of the skirting board. Dab the roller to deposit some primer, making brushing easier. Only apply a thin coat.
Switch to a flat brush for the profile section. This brush allows for better flexibility to coat the curves and grooves. Once done, check for any missed areas and touch them up.
Step 5: Priming the architrave
Architrave requires additional care due to its detailed profile and visible edges.
Unlike skirting boards, both edges of architrave are visible when fitted, so ensure they are fully coated.
Use the flat brush to handle the smaller flat sections and intricate profiles, applying a thin and even coat.
Step 6: Watching for imperfections
While priming, pay attention to a couple of common issues. First, check for loose hairs from the brush that may stick to the primer and remove them promptly. Second, watch for clumps of primer and brush them out to ensure you maintain a thin, even coat.
Step 7: Drying and sanding the first coat
Once the first coat of primer is applied, allow it to dry. For quick-dry primer, this typically takes 2 to 4 hours. After drying, sand the boards lightly with P240 sandpaper.
Use a sanding block for flat sections. Use sandpaper alone, folded as needed, for profile sections. Sandpaper pads or wire wool are also excellent options for flexibility and durability.
Step 8: Applying the second coat
After sanding, apply a second thin and even coat of primer. Once the second coat dries, repeat the light sanding process to ensure a smooth finish.
Step 9: Preparing for fitting
After two rounds of priming and sanding, the boards are ready for fitting and the application of a top coat. Take a look at our article for tips on painting skirting boards after priming.
If you choose to prime the boards after fitting them, start by using masking tape to protect the surrounding walls and floors. Keep in mind that this method may be less comfortable, particularly when working in larger rooms.