Filling Holes and Gaps – Do I use caulk, wood filler, or spackle?

Thank you to DAP for sponsoring this guide on caulk, wood filler, and spackle! All opinions are entirely my own. This post also contains affiliate links, but nothing that I wouldn’t recommend wholeheartedly. Read my full disclosure here.

There are so many different kinds of materials to fill holes and gaps in your DIY projects and around your house. Caulk, wood filler, wood putty, spackle, joint compound…just to name a few.

It’s no wonder that most DIYers and homeowners are pretty confused about what the best product is.

Whether you are filling gaps in trim and baseboards or filling nail holes, there are a lot of final finishing touches needed when you’re working on weekend DIY home projects, renovations, and woodworking projects.

Caulk Overview

Caulk or caulking is a material used to fill gaps in the seams between two materials or to seal joints. It is sold in a tube that is loaded into a caulking gun, which is used to push out the caulking into the seam. It is also sold in a squeeze tube.

Caulk is used both to make seams, joints, and corners sealed off from water, bugs, air, and/or water.

Caulk is usually made of either latex or silicone (or a combination of the two).

There are tons of different types of caulk for all sorts of renovation and construction uses, so it’s very important that you’re choosing the right caulk for the job.

What is caulk used for?

• Flexible exterior caulk is used around windows, doors, siding, and around the trim
• Flexible interior caulk is used around trim and baseboards, on the corners and edges of accent walls (like shiplap)
• Interior caulk for kitchens and bathrooms (or anywhere that may get wet or exposed to moisture) is used for all joints, corners, and gaps between two materials. For instance, where sinks meet countertops, where tile meets countertops on backsplashes, where a bathtub or shower meets the wall or floor, etc.

Learn more about the different caulk types and how to apply them!

What’s the best caulk?

Alex Flex Caulk

For interior applications for trim and molding, we love DAP’s Alex Flex Premium Molding & Trim Acrylic Latex Siliconized Sealant. It is a high-performance sealant specifically formulated for use in molding and trim applications. It delivers excellent adhesion and flexibility for a crack-proof seal. We also love that it is ready to paint within 30 minutes.

Extreme Stretch Caulk

If the caulking is needed in an area that will undergo an extreme change in temperature or possible movement, another great option is DAP’s Extreme Stretch Acrylic Urethane Premium Elastomeric Sealant. It is a high-quality caulk that is ideal for sealing a wide variety of interior & exterior surfaces. It is specially formulated to stretch over 600% ensuring the seal does not crack or lose adhesion making it perfect for most sealing projects including windows, doors, trim, siding, corner joints, sinks, and countertops.

Kwik Seal Ultra Caulk

For sealing in the kitchen and bathrooms, we love DAP’s Kwik Seal Ultra Advanced Kitchen & Bath Sealant. It is an advanced sealant formulated with innovative ultra-hydrophobic technology that repels water, dirt, and stains and offers a lifetime mold and mildew resistance guarantee so the sealant stays looking clean, fresh, and new.

Wood Filler Overview

Wood filler is a sandable material that can be applied to nail holes, gouges, cracks, gaps, and imperfections on the wood surface.

Typically wood filler is used once a project is built, but not yet stained/painted/sealed. Filling nail holes and other imperfections is one of the final steps in your woodworking projects.

Once applied and dried, you can sand it smooth and stain or paint your project.

What is wood filler used for?

• Filling nail holes in woodworking projects
• Filling gouges and imperfections in the wood
• Filling dents, gouges, and nail holes in wood trim and baseboards (that has not been stained or sealed yet)
• Smoothing cracks in wood projects
• Smoothing joints (where two pieces of wood come together)
• Shape damaged areas, like corners and edges

What is the best wood filler?

Plastic Wood X All Purpose Wood Filler

For filling nail holes, gouges, cracks, and imperfections in the woodworking projects we typically use DAP’s Plastic Wood X™ All Purpose Wood Filler with DryDex Dry Time Indicator.

One thing I love about it is that it goes on pink and dries to a natural, wood finish, so you know when it’s ready to sand! How cool is that? This patented technology eliminates the guesswork of trying to figure out when to sand and reduces the chance of errors.

The wood filler is ready-to-use and has a thick knife-grade formula that spreads easily for fast, professional repairs and can even be applied on vertical surfaces.

Plastic Wood X is stainable, paintable, and won’t shrink crack, or crumble. It can be sanded, planed, cut, drilled, screwed, or nailed once cured.

Premium Wood Filler

DAP’s Premium Wood Filler is a custom 3-in-1 wood filler, grain filler, and sealer coat. It has a unique water-based formula that allows you to more accurately match existing wood tones to create a repair that is seamless and invisible.

The Premium Wood Filler won’t sink, shrink, crack or fall out. It has strong impact resistance making it perfect for edge or crack filling. It dries fast (a little faster than Plastic Wood X), which allows you to finish your woodworking project faster.

The Premium Wood Filler has Chameleon Color Blend Technology allows you to mix stains or pigments directly into the wet state for an exact color match. Alternatively, you can also apply the stain afterward because this wood filler accepts stains, tints, pigments, dyes, and finishes.

If you want to use it as a grain filler (like if you’re painting the wood surface and don’t want to be able to see the wood grain texture through the paint) you can thin it slightly with warm water until you get to a thick paint-like consistency. Then brush it across the wood grain to fill the natural wood pores. This will provide a smooth, tabletop finish.

How to use wood filler

• Clean the surface. The area that needs filling should be clean – dry and free of dirt and sanding dust. The surface and air need to be above 40 degrees F.
• Apply wood filler. Use a clean putty knife to push wood filler into larger gouges and lightly scrape the knife flat over the surface to smooth out. For small nail holes, you can simply use your finger to press the filler into the hole. You want to overfill the repair slightly when applying the wood filler so you can sand it down to a smooth, flat finish once dry.
  • If the damaged area is deeper than 1/8″ – 1/4″, apply the wood filler in layers and let each layer dry before moving on.
• Sand smooth. Once the wood filler is dried (when it is no longer pink if using Plastic Wood X with DryDex), you can sand smooth using 150 grit sandpaper. It should take approximately 2-6 hours for shallow repairs to dry and up to 36 hours for deeper fills.
• Stain or paint. Once sanded, typically you can stain or paint over the wood filler as needed. Be sure to check the label for specific instructions so you can achieve the best finish possible.

Should I use wood filler or caulk?

To sum up the difference between caulk and wood filler, caulk is to be used to fill in corners and gaps between two materials, whereas wood filler should be used to fill nail holes and other damage on flat wooden surfaces.

Wood filler can be sanded and caulking can not.

Wood Putty Overview

Wood putty is a malleable material that is used to fill small holes and damage in woodworking and furniture. Wood putty is generally applied after the project has been completed (meaning stained, painted, and sealed).

Another use of wood putty could be treating damage on older wooden furniture or molding. Even if the piece has been sealed for years, you can find a good color match and fill the damage with wood putty.

One key feature of wood putty is that it does not harden once dried. It remains malleable over time, meaning that you cannot sand it smooth.

Plastic Wood Putty (Non-Hardening)

DAP’s Plastic Wood Putty is an easy-to-use, non-hardening wood putty that is ideal for filling small holes and minor defects in interior wood surfaces (like stained baseboards) after assembly and finishing.

It is recommended for filling and hiding countersunk nail holes, gouges, scratches, and miter joints.

Plastic Wood Putty is available in 12 popular wood tones to match most finished wood surfaces. The colors can be blended together for custom color matching.

What is the difference between wood filler and wood putty?

The key difference between wood filler and wood putty is that wood filler hardens once dried (so it can be sanded smooth) and wood putty does not.

Wood Filler can be used on interior and exterior applications (at least the products I mentioned above), whereas wood putty can be used on interior projects only.

Lastly, wood filler is meant to be used during the building process before the piece has been stained/sealed, or painted. On the other hand, wood putty is intended to be applied after the piece has been finished.

Spackle Overview

Spackle is a soft substance that is used to repair small damaged areas in drywall (like small holes, dings, and dents) and fill nail holes on walls. Spackle is typically made from gypsum plaster, glue, and other compounds.

Spackle is definitely one of those must-haves for homeowners to always keep around, especially if you’re going to be doing any interior painting.

What is spackle used for?

• Filling nail holes on the wall before painting
• Smoothing dents and dings in walls before painting a room
• Filling dents, joints, and nail holes in pre-painted or primed trim and baseboards before painting
• Filling nail holes and any imperfections on a door frame or window trim (although check your label first because some spackling is not made for door and window frames)
• Patching nail holes on accent walls, like board and batten and faux shiplap
• Repairing a small crack in drywall

Spackle is used before painting a room to repair damage to the walls, like nail holes and dents and dings.

What is the best type of spackle?

DAP makes several different spackling products that fit different uses, jobs, and budgets. Here are 4 of our favorites!

DryDex Spackling

DAP’s DryDex Spackling is America’s #1 seller and generally where we turn first when we are filling holes before painting. DryDex Spackling shouldn’t shrink or crack after being applied.

Just like Plastic Wood X wood filler, it contains a patented DryDex Dry Time Indicator causing the product to change color when optimum dry time is achieved, which is generally 1 to 5 hours. It goes on pink and turns white when dry! This unique feature is the indicator that it is ready to sand and paint.

Alex Flex Flexible Spackle

If the area you’re patching has a tendency to crack and you’ve experienced reoccurring cracks in drywall, you should go with DAP’s Alex Flex Flexible Spackling. It is similar to DryDex spackle, in that it won’t shrink or crack and is sandable and paintable – but it is more flexible.

Fast Dry Premium Spackling

If you’re in a hurry and don’t want to wait for 1 to 5 hours for the spackle to fully dry before sanding and painting, you can use DAP’s Fast Dry Premium Spackling. It has an 8x faster dry time when compared to traditional heavyweight spackling and is usually ready to paint in just 15 minutes.

Alex Plus Spackling

DAP’s Alex Plus Spackling is another great option for filling holes & cracks in surfaces such as drywall, plaster, wood, brick, metal, and stone. It has a ready-to-use, smooth white formula that spreads easily for fast, professional repairs that will not sink, shrink or crack.

How do you use spackle?

• Clean the surface. The area that needs patching should be clean – dry and free of dirt and dust. If you need to learn more about how to clean walls before painting, check out this tutorial.
• Apply spackle. Stir up spackle using a putty knife. Use a clean putty knife to push spackle into holes and damaged areas, then lightly scrape the knife flat over the surface to smooth out. For small nail holes, you can simply use your finger to press the spackle into the hole. You want to overfill the repair slightly when applying the spackling so you can sand it down to a smooth, flat finish once dry.
  • To get better adhesion to your surface, lightly sand the surface first with a sanding block to d-gloss the surface.
  • If the damaged area is deeper than 1/8″ – 1/4″, apply the spackle in layers and let each layer dry before moving on.
• Sand smooth. Once the spackling is dried (when it is no longer pink if using DryDex), you can sand smooth using a sanding block. Dry time is generally 1-5 hours. You can always touch the surface to see if it is dry and if your sandpaper becomes clogged with spackling, wait and let the repair dry longer before sanding to a smooth finish.
  • If you’re in a hurry, try Fast Dry Spackling for a 15 min paint-ready dry time.
  • For a smoother finish, dip your putty knife into water and lightly smooth spackling prior to drying.
  • Use a dual-grit sanding block for a nice and smooth finish. Start with medium (60-100 grit) and then finish with fine-grit (120-220 grit).
• Paint. Once sanded, you can paint the surface.

What’s the difference between spackle and wood filler?

The difference between spackle and wood filler may be hard to tell because they both fill holes on flat surfaces before painting and they are both sandable.

But the key difference between spackle and wood filler is that spackle is not stainable like wood filler is. So if you are planning to stain your project – wood filler is definitely the right choice.

Going further, wood filler and spackle are made a lot differently – even though they do some of the same things (like fill holes).

Wood filler is designed to cling and stick to wood, whereas spackle is made to adhere to drywall, stone, and plaster. This is one reason why you should stick to wood filler for wood and spackle for walls.

Can you use spackle as wood filler?

One of the big questions you’re probably wondering is “can you use spackle as wood filler?” The answer is technically yes, it will usually “do the job”. If you’re in a pinch and that’s all you have and you only need to fill one small hole – sure, go ahead. However, wood filler is generally the better option when you’re working directly with raw wood.

What’s the difference between spackle vs caulk?

To sum up the difference between spackle vs caulk, caulk is to be used to fill in corners and gaps between two materials, whereas spackle should be used to fill nail holes and other damage on flat surfaces (walls and/or trim).

Spackle can be sanded and caulk cannot.

Joint Compound Overview

Joint Compound (also called drywall mud or mud) is a wet substance that is applied over the top of drywall to seal joints and create texture and a base for painting on interior walls and ceilings.

Joint compound is usually made with gypsum dust, water, and other ingredients. Sometimes it is sold as a dry powder that gets mixed with water and other products sell it as a pre-mixed material.

Is spackle the same as joint compound?

Although spackle and joint compound have similar jobs, they are very different. Joint compound is much runnier than spackle and, therefore, dries much slower than spackle (24 hours for joint compound vs 1-5 hours for spackle).

Joint compound should be used when texturing drywall or repairing large areas of damaged drywall. Spackle is best used for filling smaller holes and damage in drywall.

Joint compound definitely needs to be primed before painting, whereas many high-quality spackling products can be painted without priming first.

What’s the best filler for the job?

We’ve covered a lot in this guide for filling holes and gaps, so we thought we would sum it up with a list of basically everything job you will find in renovations and DIY projects and end the debate on what product to use. No more wondering about spackle vs caulk or wood filler vs caulk!

Below you’ll find a list of every product (caulk, wood filler, wood putty, and spackle) that we mentioned in the guide and a short bullet-point list of what to use the product on.

There are so many different products out there for filling holes and gaps in your DIY project, it’s easy to be confused. Hopefully, by using this guide, you now know if you should use wood filler vs caulk or spackle vs caulk on your next project.

You can confidently head to the hardware store and purchase your supplies knowing that you’re buying the best filler material for your project!

Do you have any other questions about filling holes and gaps in your projects?

Let us know in the comments below!