The BEST Way To Fill Nail Holes In Trim

Why Should You Be Filling Nail Holes in Trim?

Have you ever entered a beautifully furnished house with spectacular finishes but are put off by glaring nail holes? So what is the best way to fill nail holes in trim and avoid such embarrassments?

These nail holes may seem ignorable, or you can easily conceal them using a coat of paint, but you cannot hide in reality. So it would be best if you filled up even the tiniest of holes.

man sanding nail holes on white trim board

How to Fill Nail Holes in Trim

Filling nail holes in trim is not rocket science. Just a few steps to follow, and the appearance of your trim is so neat. Most trims are MDF (medium-density fiberboard). 

When you expose MDF boards to excess moisture in the form of water-based paint, and if you use the putty, it balloon’s out like pressed wood. The putty technique mostly results in divots inside the hole and a bump outside. 

The following is a step by step process of how to fill nail holes in trim and yield heart satisfying results:

Step 1: Brush Paint or Spray the MDF Boards

Give your MDF boards a good coat of paint, even if they are already pre-primed. Then, you only need to paint the nail holes and not the baseboard.

Step 2: Cut Trim Piece or Baseboard to Height

Using a miter saw, cut your trim to the required height.

Step 3: Nail Gun the Trim or Baseboard to the Wall

Use a pneumatic nail gun, preferably with an air compressor.

Step 4: Caulk Seams with Filler

Caulking is one critical step, and you will require a headlamp to spot imperfections. Next, apply caulk along the length of the seam, then using your finger, run through it, wiping its excess. Unfortunately, you will put half the caulk to waste. Keep a small mug of water close by to rewet your hand and a damp cloth which will help to create consistency as you apply. 

The debate is between putty vs. caulk; which is the best thing to fill nail holes in trim? Here is something to remember: Putty is a dough-like substance that fills nail holes in trim and other open space surface defects. In contrast, caulking was the process of filling in seams in between planks to make the water vessel watertight. 

Today, caulk hides gaps in woodwork, fills along the narrow crack in walls, and fills nail holes in trim in the process.

Step 5: Sand the Nail Holes

Using 180- 220 grit sandpaper, sand the board smoothly. You will be sanding out the mushroom caused by the nail gun pressure that made it balloon out of the hole. 

Step 6: Remove Dust Out of nail Holes

Vacuum the dust from the hole and wipe it clean with a damp cloth, which will help when you trim putty so that it does not expand and you’re back to the mushroom shape again. 

Step 7: Make Use of Lightweight Putty

Use a light putty on the nail hole and allow it to dry overnight. The best putty to fill nail holes is lightweight because it will rise (mushroom) less. Avoid the heavy pink putty; keep it for drywall. Remember to get a small container of light putty as it dries out faster. 

As long as they are lightweight, a spackle or wood fillers for nail holes will do justice to your nail hole. A pro tip to remember is that in-between applications, close the wood filler to prevent it from hardening. 

Step 8: Sand the Holes

Sand putty holes the next day after the lightweight putty has dried up. Use a sanding block and 180 – 220 grit sandpaper.

Step 9: Repeat the Process

Apply a coat of lightweight putty again for filling nail holes. Usually, the putty collapses inside. Make sure you level the divot perfectly. It will take a short time to dry than the overnight duration, then sand again.

Step 10: Wipe the Dust Off Lightly With a Damp Cloth

After the sanding process, you will notice that dust has accumulated on the surface. Carefully wipe off the dust.

Step 11: Feel the Trim

Run your fingers over the trim. Do you feel any bumps? If your answer is yes, it means it’s not well done. Perfectly done trims are smooth. We prefer you close your eyes to avoid bias in your judgment. Put the putty again if it’s necessary. 

To know whether a hole is ready to paint, sand off the edges of the mushroomed nail hole, the putty fits perfectly in the spot, and sand off the pre-painted board.

Step 12: Oil Primer

Over the puttied areas, apply a thin film of oil-based primer and the exposed ends of MDF to seal it. Let it dry off. Use the oil to fill the exposed pressed fiberboard, or else water-based paint will make it rise (mushroom). 

Step 13: Water-Based Paint

Here comes the fun part, painting! Select your preferred method to get a straight wall-trim paint line. From here, use your preferred way to get a perfectly straight wall-trim paint line. You can use tape and a double-cut method to block paint perfectly. 

On the seam of the wall, line the painter’s tape to restrict the area you want to paint. If your wall is red and the trim white, paint the edge of the tape with red to seal the tape. When you paint white on it, it’s likely to leak. To prevent it from leaking, use the painter’s tape. 

Apply two coats of paint on the trim, being cautious not to get paint onto your floor. At this point, peel off the tape while the second coat is still wet and do it at a sharp angle.

using nail gun in kitchen

What to Fill Nail Holes With

Isn’t it amazing that your DIY project of nail hole filling does not need a lot? With readily available and few items, you get the work done. For a fantastic look, make sure the filler matches the white trim. If the trim is a white pre-finished trim, the trim should also be white.

These are some of what to fill nail holes with:

  • Clean and dry cloth
  • Fine-grit sandpaper
  • Hand sanding block
  • Putty 
  • Putty knife of 2 inches (5 centimeters)
  • Whitewood filling compound

Which Wood Filler Should I Use?

There are different ways of categorizing wood fillers for trim. The key is to select the type of wood filler for trim to give the best results. You can classify wood fillers as either solvent-based or water-based. Water-based comes with a creamy consistency. You will find it easy to apply and clean. 

Solvent-based have a sticky and oily consistency but make up for a solid and sticky texture. However, such a rock-hard and sticky texture makes it hard to clean up. MDF, wood trim, and drywall have a nail hole filler suitable. The following is an in-depth discussion of some of the ideal fillers for this purpose. 

Which Types of Nail Hole Filler is ideal for Wood Trim, MDF & Drywall Filling?

Cellulose-Based Nail Hole Fillers

These are wood fillers that fulfill their purpose of hole filling and are helpful for staining purposes. You will find it at the convenience store at an affordable price. You can also find them as premixed solvents, which are quick to dry. 

You will find this mixer in powder form that you can be mix with alcohol or water. This type of nail hole filler has stood the test of time as it is long-lasting and has a long shelf life. It will give your trim a fabulous finish with a patch that’s long-term.  

Epoxy-Based Nail Hole Fillers

It provides a fantastic choice for nail filling for outdoor use because of its high resistance to water and fast-drying properties. In addition, these wood fillers assure you of excellent performance and effective binding.  

These wood fillers are made of petroleum, making them super effective at sealing MDF and wood. In addition, the wood fillers are resistant to high temperatures and can withstand tear and wear. 

Gypsum-Based Nail Hole Fillers

Gypsum-based nail hole fillers are suitable for indoor applications. They have a powdery formula that includes crystalline minerals. Mix this powder with solvents, and use it to patch up holes.  

When applied on your surface, they deliver a shiny luster, appealing to the eye. For indoor applications, gypsum-based nail hole fillers are one of the best.

The downside to this nail hole filler is that they stain easily. Because of that, you will have to put a coat of paint over the wood to make it last longer. But, ultimately, the properties and functionality of his nail hole filler make it a perfect choice. 

Vinyl-Based Nail Hole Fillers

These nail hole fillers are made of calcium carbonate and poly-acetate and are considered the least durable ones. These nail hole fillers have emulsion for excellent binding. However, they work well on small coats and are helpful for added protection. 

Despite their drawbacks, they are lightweight and fluffy. Use them on MDF for filling nail holes. Also, because of their plastic consistency, they make excellent fillers for outdoor MDF.  

man using a nail gun


Nail hole filling can be a tedious affair, but you will enjoy doing it if you understand how it goes. You need a nail procedure and the right tools to get the job done. With a bit of direction from someone with more skill than you or an expert, you will have all your nail holes filled!

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