Time: Varies
Skill Level: Medium
Project Cost: $75-$100
Professional Cost: NA
Tools you Need

Don’t stop at your walls. Learn how to prep trim for painting.

Prepping and repairing trim is a project of its own but can also be a part of a larger project, such as painting rooms, wallpaper and skim coating walls. Bauen recommends learning how to prep trim because it can visually make a big different in your room. You might be thinking, why waste the time? Just rip it out and replace it. Bauen opts to repair, especially in older homes because matching original trim can be very difficult and potentially expensive. It is important to remember that anytime you are repairing something old there is a good chance it will not look brand new. This is especially true with trim. Just keep in mind that in this project you are striving for imperfect perfection.


Gaps are very common in older homes and even appear in newer construction. Why does this happen? You might not realize it, but your house moves. It expands and contracts ever so slightly with temperature changes and humidity levels as well as external ground movements. As the temperature in your house cools, materials contract and vice versa when the temperature increases. Wood trim is especially susceptible to these temperature fluctuations. The continuous expansion/contraction causes the trim to slowly move. A secondary reason for gaps is uneven surfaces. Often times, walls, ceilings and floors are not straight!

Besides aesthetic reasons, fixing gaps and cracks is actually in important in trim that meets exterior floors, walls and ceilings. You might not know this but up to 30% of heat lost in a home is due to cracks, crevices and gaps. We recommend taking the time to fill these areas to ensure a nice warm cozy home.

Below are the various types of trim prep we will teach you.


bauen-b ottom Line. Take the time to use putty for holes and caulk for gaps. Each serves a specific purpose. REMEMBER…PERFECT IMPERFECTION!!


Assess your trim before starting and ask yourself the following questions.

1. Was your house built prior to 1970?
If yes, there is a chance you have lead paint either exposed or in sub-paint layers. Lead paint=no good. Lead paint is most harmful when dispersed through the air in tiny particles such as sanding dust. Bauen recommends you perform a lead test if you plan on scrapping or sanding during your prep phase.

LEARN ALL ABOUT LEAD PAINT – Click to learn more.

2. What is the extent of your damaged trim?
Bauen loves keeping the originals, but sometimes things are damaged beyond repair. Only you can tell if it is worth saving, but if you aren’t sure, send us a pic and we can let you know our thoughts.

3. Is your existing trim paint oil paint?
If you are not sure, perform a test. To do so, take a q-tip, paper towel or cotton swab and soak it in rubbing alcohol. Rub a section of trim. If the paint comes off, you have latex paint, if not, it is oil. This is important to know when it comes time to picking trim paints. It also might explain why you have peeling paint. Often times, latex paint applied over oil paint without a primer will result in peeling. Remember that saying, oil and water don’t mix? A primer needs to be applied to have a smooth, durable transition. We will go into this in more detail later on.

ottom Line. Do a lead test. It is inexpensive and can help keep your mind at ease and yourself and your family safe.


Prep for painting if that’s your plan.

1. Protect your furniture. If you are working on the entire room, it would be advisable to cover your furniture or remove it from the room. Dust can magically find its way into just about anything.

2. Protect your floors. Cover floors with your plastic drop cloths and secure then to the baseboard using paint specific tape. Bauen likes 2 millimeter drop cloths because they have decent thickness and won’t rip easily.

3. Protect yourself. Wear a N-95 or N-100 sanding respirator and googles when sanding, scrapping and dusting. Once again, compound dust is fine and can find its way into ANYWHERE. Gloves are optional, but recommended if you have sensitive skin or a fantastic manicure.

LEARN ALL ABOUT RESPIRATORS – Click to learn more.

bauen-b ottom Line. Definitely take the time to prep your space. No one wants to pick out dust fragments from wood flooring.


Time to stop staring into those dark spaces

The trim you see above is sadly a great example of gaps and small holes you will find in trim. As you can see, the trim has pulled away from the ceiling. This should be expected in a house built in 1929. The holes you see are nail holes from a power nailer. This is a common tool used by contractors during renovations.

1. Remove debris. Remove loose debris from the area. This might include peeling paint and splintered wood.

how to repair crown molding apply putty

2. Fill with putty. Fill nail holes, gaps and uneven surfaces with filler putty. For these types of repairs, we like to use a thick patching putty that dries to a hard yet sandable finish. You can use your fingers for small areas or a 2″ putty knife for application. Don’t worry if you put too much on because you will sand it down. Allow the putty to dry.

how to repair crown molding sanding

3. Sand. Sand down the putty using a fine sanding pad. Use medium pressure. This is a good time to wear protective goggles and a N-95 or N-100 respirator. Run your hands over the area to make sure you sand it down to the same level as the trim. This is helpful because you might think the putty is the same level, but in fact it is slightly raised. This becomes noticeable when you start the painting process.

4. Wipe down. Wipe down the area with an ever so slightly damp cloth. You need to clean the area because caulk, primer and paint do not stick to debris and dust.

caulk trim corners

5. Caulk. Use a paintable white caulk to fill the gaps. Caulk is preferred over putty for filling gaps because of caulk’s flexibility. Inevitably, the caulk will come out thicker than you need. Use your finger to smooth it down. Wear tight fitting gloves if you want to protect your hands. Let the caulk dry according to the dry time on the label. There are fast drying caulks that are paintable in 30 minutes.

how to repair crown molding painting

6. Prime and Paint. You are done and now it’s time to prime and paint! Look how clean your trim looks!

paint trim

Reclaim your trim and bring it back to life.

Time is not kind to trim. Cracks and paint build up are very common as the years pass. As you can see in the image above, the area where the trim meets the wall is cracked and has years of paint build up. This paint and caulk build up has lead to the edges being rounded and ragged. For most of you out there, the cracked trim will bother you more than the rounded edges. The simple way to fix this is to just caulk the trim as shown below. This is a good route to go if you have lead paint and do not want to rustle it up. However, if you want to go all the way and regain those crisp edges follow all the steps below. Following all of these steps is particularly good to do if you are installing wallpaper, which we will be doing here. Instead of the wallpaper ending on irregular edges, the wallpaper will end on a crisp flat area.

Remove the gunk

1. Scrape One Way. Start by scrapping parallel with the top of the trim using your painter’s tool. Position the tool at a sharp angle to the trim. The more perpendicular you are to the trim, the greater the chance you have of gouging the wood. Start scrapping will gentle pressure and gradually push harder until you find the right pressure.

2. Scrape the Other Way. Now position your painter’s tool perpendicular to the trim top as shown in the image above. The purpose for going this way is to cut through the old putty and paint that is attached to the wall.The painter’s tool has two different ends. The pointy one is great for starting the scraping process. Switch to the flatter end once you get going. You are less likely to dig into the trim using this end.

3. Remove. Periodically remove debris from the area before moving on to the patching phase. As you can see here the existing strip of caulk is coming up nicely. Don’t worry if you accidentally take off a piece of the trim. We will show you how to nicely patch it.

Patch it up

There is a chance your painter’s tool dug into the wall as you were scrapping. This is no biggie. Use your setting compound to fill in areas that might be missing. We like setting compound as opposed to a pre-mixed patching putty because setting compound dries extremely hard.


4. Mix the compound. Pour 2 cups of setting compound powder into the mixing cup and add a small amount of water until you produce a consistency that is a little thicker than cake icing. A good test is to put some on your putty knife and turn upside down. If it stays put, then you are good to go. Mix thoroughly and quickly since the compound starts to harden once water hits it.

  • completed setting compound application

5. Application time. Use your 2 inch putty knife to apply the compound over the damaged area. Apply liberally! You will sand at the end so it IS ok to put a little extra on. Clean your putty knife after application using water and soap. Dry thoroughly with a rag to prevent rusting.

6. Let the compound dry. Dry times can vary and are affected by the humidity and temperature in the room. The compound’s color will lighten and will be rock hard – this is how you know it is dry. You might need to apply a second coat of compound if the applied compound sits below the wall level.

Sand it


7. Sand. Use a fine sanding pad and sand down the setting compound so that it is level with the wall. If you got a little compound happy, you can start with a medium sanding pad to remove the top layer. Make sure to switch to a fine pad once you get close to wall level to get it extra smooth.

8. Wipe it. Remove the compound dust and wipe down with an ever so slightly microfiber cloth. Microfiber cloths are great because dust latches onto these cloths. You want to have a clean surface for the caulk and primer/paint.

Caulk it


9. Apply Caulk. Apply a paintable white caulk to the trim. Even if you don’t see a gap, it is good to apply it anyway. Move slowly. You will notice the caulk releases thicker than intended. Use your finger to smooth down the caulk and remove the excess. This will allow you to create a smooth transition from caulk to substrate. Wear tight fitting gloves if you want to protect your precious fingers. Allow the caulk to dry according to the label. FYI, caulks come in ready to use tubes and cartridges that require a caulking gun. In the long run, the cartridge method is more economical.

10. Prime and paint. Time to move on to the fun stuff – prime and paint!

repaired gouged trim

Time to bring out the sculptor in you

Sometimes you wonder why people do what they do. As you can see here, someone decided to remove a chunk of wood trim. Why?? We have no idea. Before freaking out, you should realize you do have options. If you know you can find the exact trim, then replacement would be a good option. However, in this situation, the trim is from 1929, so we don’t want to take the chance. So what to do you might ask? Time to sculpt it back to life using a pre-mixed wood filler.

1. Remove debris. Remove any loose debris in the area. This will include paint chips, wood splinters and wall fragments.


2. Apply wood filler. Apply wood filler using a 2″ or smaller putty knife. The filler is pretty tacky so it will take you a few passes back and forth to get it nice and smooth. Allow the filler to dry. The gouge you see above took a few hours to dry. For especially deeps gouges you might need to do two passes of wood filler. To do this, fill the gouge half way with putty. Let it dry. Fill the remaining space and allow to dry again. You might be inclined to fill it in one shot, but unfortunately the putty can crack if there is too much of it.

3. Sand and sculpt. Use both sanding pads and sanding sheets to sculpt the filler to match your trim. Follow the groves left and right. It is better to work slowly and not take off too much.4. Wipe. Wipe down the area with an ever so slightly damp microfiber cloth. Now it’s time to paint!


Peeling paint on trim can be a real pain. Peeling paint can occur when latex paint is painted over oil-based paint without using a primer. The images you see above are an example of it. Peeling paint is highly common on aging trim. Peeling paint on older trim can often times be more severe and involve more layers. More layers, means more unevenness along the trim. NOTE: Absolutely perform a lead test before scraping or sanding. You are almost guaranteed to have lead paint in a sublayer if your house is older than 1978.

Just a little peeling paint

1. Peel and sand. Peel off the loose pieces of paint and then sand using a fine sanding pad. The goal is to smooth down the edges of the top coat of paint so that it creates a smooth transition from bottom coat to top coat.

2. Proper priming. Use a high quality acrylic bonding primer before painting.

More than just a little peeling paint

1. Scrape. Use your painter’s tool to scrape away any loose paint. Keep the painter’s tool at a tight angle to the trim. The more perpendicular you are to the trim, the greater the chance you have of gouging the trim. If you are lucky, the paint will come up easily.

2. Fill. Fill any uneven areas using your patching putty. Apply puttying using a 2″ or 4″ putty knife, depending on the size being filled. Allow to putty to dry.

3. Sand. Sand down the dried patching putty using a fine sanding pad. Use medium pressure, making sure to not take off too much putty.

4. Wipe. Wipe down area using a very lightly dampened microfiber cloth.

5. Prime and paint. Do it the right way and prime before painting.

bauen-b ottom Line. Take the time to use putty for holes and caulk for gaps. Each serves a specific purpose. REMEMBER…PERFECT IMPERFECTION!!

Ready to start repairing your trim?

Time to take the guesswork out of what products to buy. Purchase our project kit that includes all the tools needed for a successful repair job. Below are three individual project kits tailored to each type of repair covered in this How To.

large gouge in trim
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Economy vs. Premium
trim with gaps and cracks
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Economy vs. Premium
trim with cracks
Price from: $33.06
Price from: $40.61
Economy vs. Premium