How to paint wall trim: 10 steps (with pictures)

How to paint wall trim: 10 steps (with pictures)
How to paint wall trim: 10 steps (with pictures)

It is often the wood trim (moldings, cornices or decorative strips) that give a room all its character, especially if they are well painted. Regularly, however, they must be repainted. This finishing job can seem difficult and messy to some who prefer to leave it to a specialist. However, if you have the time and are a little careful, this is a job within your reach and you will save quite a bit of money.


Part 1 of 2: prepare the toppings

Paint Trim Step 1

Step 1. Decide where you are going to paint your trim

In principle, there is no difference between painting them on site or dismantled. In both cases, there are advantages and disadvantages.

  • If you want to paint them in your garage or outdoors, be aware that you will have to remove them from the wall, which takes time and you can damage them. On the other hand, it is more practical to work, because the fittings are at the right height and we do a better job.
  • If you paint them in place, you save time for disassembly. On the other hand, you will have to work on a stepladder, in positions that are sometimes impossible and you will have to apply masking tape to avoid dirtying anything.
Paint Trim Step 2

Step 2. Gather materials and supplies

On the preparation side, you will need sandpaper for increasingly fine sanding (grit 80, 100 and 120), filler, a spatula to be coated, paint for undercoat, whatever. make caulking (gun) and masking tape. When it comes to painting, you need good brushes the size of which is appropriate for the materials you have to paint, a roller with a foam sleeve and paint for the various final coats. Eventually, in case of dismantling, you will need a sealant to redo the joints of the gaskets.

  • As long as you do things, you might as well take a good quality paint. The rendering will be more beautiful and your work will last longer.
  • Before you go to the store, measure the area you are going to have to paint, without forgetting any part.

Step 3. Carefully sand your trim

This operation makes it possible to get rid of the old coating so as to have a very clean and very smooth base. The end result depends a lot on the sanding. This operation is as important on old painted or waxed linings as on new linings, generally covered with a protective product. If you have trim that has been visibly covered with multiple coats of paint, start with coarse-grit sandpaper (size 80). Then, the biggest removed, pass from 100 and finally, from 120. You will thus have a very soft wood to the touch.

  • If your fillings are raw or already pickled, a fine sanding with 120 grit sandpaper is sufficient.
  • When you sand and want a perfect job, you have to insist on the hollow parts, the patterns. Take your time and use fine tools to get to the bottom of the crevices.

Step 4. Repair any damage to your upholstery

This mainly concerns old gaskets which may have hollows, cracks, pitting, sometimes original. These defects must be repaired before painting. For this, take a wood putty and fill in any defects by hand or using a spatula. Remove the excess with the spatula. For putty, read the instructions for use. Allow the putty to dry for several hours before sanding with very fine sandpaper.

Step 5. If your trim remains in place, protect surrounding areas before painting

Protect the walls, the adjacent frames over a width of a few centimeters using a slightly wide masking tape. Also protect the ground with a tarp to avoid doing too much damage. Apply this tape as precisely as possible so as not to have to touch up.

Part 2 of 2: paint the trim carefully

Step 1. Apply an undercoat known as a “tie coat”

Pour your paint in a paint container (with a tray and a grid to drain) and prepare your brushes (in general, you take a brush already used that will not lose its hairs!). Spread the paint well along the grain (usually lengthwise). Apply one or two underlayments depending on the type of wood. Thus, the grain and color of the original wood disappear. Your final painting will “hang” well. This layer must be covering, but very thin. Indeed, if you put a lot of it, there will inevitably be extra thicknesses, and it will be seen in the end.

Step 2. Apply a first final coat of paint

Lightly sand the undercoat and dust well. The first layer is very important, you should not see the brushstrokes. The more you apply yourself to stretch the paint, the better. As with the undercoat, pour your paint into a paint container. Immerse your brush or roller, then drain it well, nothing should leak from the tool. Start in the center of the filling and paint the first half in regular, horizontal back and forth strokes. Do the second half. At the end, pass a foam roller to make the brushstrokes disappear.

  • Be sure to iron over the paint jobs, those places that have already had time to dry. So you won't have any mark.
  • In the case of painting on existing gaskets, we always start with the edges (in contact with the masking tape) before painting the central parts.
  • Let this first coat dry for several hours (even days for an oil painting) before applying the second coat.

Step 3. Apply the second coat

Sand the undercoat very lightly (grain 400) and dust well. The second layer allows you to have a very smooth surface and to intensify the color you have chosen. It also allows you to hide previous brushstrokes. Spread the paint well lengthwise. You always need a second, even coat, even if the first one looks perfect overall. Do not have fun repainting only the slightly duller parts, we will see the differences in color. At the end, pass a foam roller to make the brushstrokes disappear.

Step 4. Replace the trim or remove the masking tape

If you painted your trim in your garage, it's time to put them back in place after they've dried. If they remained on the walls, remove fairly quickly (15 minutes) after painting the masking tape which will then be more difficult to remove. You can also fold the tarpaulin on the ground.

Step 5. Fill in the gaps between your walls and trim

Many forget this step, yet it is about the final appearance of the piece! The caulk provides a nice finish and will prevent further warping of the trim. Using a caulking gun, spread the product precisely between the wall and the trim, using a tapered tip. You can also use your finger to push the caulk into the free space and to equalize it. This done, clean the trim and your tools (gun, nozzle) well with a damp cloth. Wash your hands right away.

  • Choose a caulk color that works well with your trim - most often white, the idea being that it should not be visible.
  • Let the caulk dry for several hours before rearranging the room.


  • With your brush, make wide movements to stretch the paint well. Thus, the paint will stretch perfectly when drying and you will have a rendering close to perfection.
  • If you paint with a roller, take foam sleeves, you will have a perfect stretch.


  • Paint in a well ventilated area. Paint fumes can be toxic.
  • Do not allow your children and pets access to a room in which you have just done painting.

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