How to Paint a Window Sill

Wooden window sills and window frames attract a lot of moisture in old homes and can fall into disrepair easily. So, we have made this simple guide showing you how to paint a window sill so you can gaze, day dreaming out the window, instead of fretting over it lingering on your to do list!


Step 1. Protect the room.

Before your start painting your window sill, lay a dust sheet to protect the floor.

Our first step is always to ready the area we are in for painting. Remove any furniture or decorations. Take down any curtains or blinds. Lay a Seriously Good Dust Sheet to keep dust down when you sand the area and stop any paint from seeping through to damage the floor underneath. Finally use some Seriously Good UV Tape to protect the windows and the wall around the window sill and window frame you will be painting.


Step 2. Prepare the surface.

Wood preparation can be tricky as areas of trim such as window sills can often be left alone for a very long time. We have written an in-depth guide on how to prepare a wooden surface for painting and we recommend you take a look.

You need to get a smooth matt surface to paint on, this can mean just sanding the surface of the wood with some Ultimate Fine Sandpaper and a Seriously Good Cork Sanding Block. Or it can mean using chemicals and lots of protective gear to strip the paint right back.

Sand the window sill smooth, before painting.

Clean the dust away with a cloth.

The next step after sanding is cleaning the dust away. Then filling and repair of any holes or cracks in the woodwork. Once the wood filler has cured, sand and clean the surface again.


Step 3. Undercoat.

There are 2 main areas you will need to prime. The first in the detail area. This is the window frame and the edges of the window sill. When working with wood we recommend using a stain block primer just in case any sap or contaminants from the wood come through. Use the Taskmaster Short Flat Brush to paint the primer on.

Paint a top coat to prime the surface.

For large flat areas such as the shelf of the window sill use the Taskmaster Gloss 4 inch Roller. When you have finished, clean the brushes using some white spirit in a sealable jar. Work the white spirit into the brush and then wipe away the paint with some Seriously Good Paper Towels. Repeat this cleaning process as necessary until the brush is clean and ready to be reused in the next step. You cannot re-use the gloss roller sleeve, but you can wrap it in cling film for use priming another part of the house. This should keep the roller sleeve moist and usable for around 48 hours.


Step 4. Apply the top coat.

Lightly sand the priming coat until smooth.

Before applying the topcoat we recommend giving the primed surface a quick, light sand using some Ultimate Fine Sandpaper. This helps remove any brush marks from the priming stage and gives a smoother finish. Clean the area one final time with a Seriously Good Microfibre Cloth to remove all the dust.

Repeat the painting steps using the Taskmaster Short Flat Brush or a 4 Inch Roller and Taskmaster Gloss Roller Sleeves for the flat surfaces. Remember you can clean the brushes and keep them for use again and again. Have you enjoyed this guide, How to paint a window sill? Try our guide, how to get a smooth finish with gloss paint. Here we show you the final magical process needed to get a glass like finish on your wooden trim.

Apply the top coat and lay off by lightly painting in long strokes.

Interior Woodwork
Interior Woodwork

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