Before you add the final touches and repaint your newly renovated room, you must ensure all the gaps and holes are filled in and sealed, so everything is nice, secure, and ready for painting.
But many people are confused about what product they should use to seal everything up. Should I use one sealer for the whole room? Do I need different products depending on whether I’m sealing drywall or a kitchen sink?
You must choose the right filler for the correct application, or you may have to redo work later down the line. So in this article, we’re going to cover all the main differences between Caulk and Spackle, so you can be 100% sure that you’re using the suitable filler for the job.
The main difference between caulk and spackle is that caulk is used to seal trims and small gaps. Traditionally in between two different items, such as where a windowframe meets a wall or where a countertop meets a backsplash. You’ll also see it used a lot in the bathroom to waterproof around the edge of the sink or bath.
Spackle, on the other hand, is technically just a brand name for 1 type of filler. But due to its popularity, it’s become a generic term for all fillers used for filling drywall surfaces. Unlike caulk’s water-resistant rubbery texture, this can be sanded and painted down, which most caulk cannot.
To a degree, and in certain situations, these can be interchanged. But these kinds of applications are few and far between. It’s essential to use them for their intended task, so let’s take a deeper look at how these two items differ.
What is caulk?
While it is technically a filler, just like spackle, its core properties, intended use, and application methods differ heavily.
Caulk is not just a filler. It’s a sealant and is usually used to seal around the edges of items. You’ll see it all over your home, lining the edges of a bath or countertops to make it waterproof and preventing any liquid from making its way into a spot you cannot reach and becoming moldy. It will also be completely airtight.
Caulk usually comes in a long tube which is loaded into something called a ‘caulking gun.’ This gun forces the caulk out of the tip, where a thick liquid flows out and can be traced around the edges of surfaces to seal it.
It has a certain degree of elasticity and flexibility due to being made from a kind of latex compound (or certain brands will also be a type of silicon). This means it won’t crack or chip over time and is easier to be wiped down.
This kind of sealant cannot be sanded due to its rubbery texture. This means it’s usually applied in 1 pass as it’s pretty tricky to reshape after it’s dried.
Because of this, some people will still use caulk for other purposes, such as filling in a small gap in woodwork, as it’s often easier to apply than filler – but that’s not its original intended purpose.
What is spackle?
Spackle usually comes in a tub and is applied more as a paste. Although certain brands will still come in a tube that can be pumped out with a consistency similar to caulk, these are not used with a caulk gun.
The name spackle is often used as an umbrella term for all kinds of fillers, extending to things like wood and body fillers. However, when referring to the actual brand, spackle is a kind of wallboard filler intended to fill in gaps such as nail holes in drywall.
Spackle can be easily sanded flat and finished, making it much more forgiving in its application as you can address the excess after.
It can’t be used for the sealing that caulk is used for as it doesn’t provide that waterproof and airtight seal.
What are the differences between caulk and spackle?
While these are both labeled as sealant types, under a bit of scrutiny, you will soon discover that their properties can, in some cases, make them unsuitable for particular kinds of jobs.
So it’s essential to be informed of their differences to be sure you purchase the correct filler for the right job. Let’s take a look at their main differences.
1. Method of application
Caulk
Caulk will usually be purchased in a long tube which is then applied to the surface using a caulk gun. This will feed the caulk out of a tight nozzle to give you a smooth and accurate line of sealant, which you run along the edge of a surface to ‘seal’ it against another surface.
Once it’s applied, you will have a little time to clean the caulk and get it as neat as possible, but once it’s dry, it’s pretty tricky to sand reshape, making it reasonably unforgiving in its application compared to spackle.
However, as spackle is sometimes used as a filler for other surface types, it can also be pumped out and applied using a knife, much like spackle.
Spackle
Spackle is more akin to a kind of putty. It will usually be purchased in a plastic tub or can and then applied to the area by hand instead of with a gun.
Spackle can be used to fill in large areas, and, overall is pretty forgiving in its application as it can be easily sanded down and prepared for painting after it’s dry.
2. Intended uses
Caulk
Because caulk cannot be used to seal in large areas, it’s generally used for sealing a small gap between two surfaces. This can include sealing the edges of sinks, baths, countertops, walls, windows – and the thin gap that needs sealing against air and water.
Ignoring its superior sealant properties, people also like caulk for these kinds of seals as they create a nice transition pleasing to the eye.
Spackle
Spackle is primarily used to fill holes, gaps, or damage in drywall. But that is when referring to the ‘brand’ spackle. But much like terms such as Xerox or the Walkman, it’s essential to understand that spackle is also used as a generic term for all fillers.
This could mean (depending on the brand) something like a wood filler or even the kind of filler used on cars to fill in dents.
3. Sealant properties
Caulk
There is a good reason why caulk is generally used for surfaces with water running over them, such as around a shower, or must be wiped down very often, such as in a kitchen. This is because it’s both waterproof and airtight.
This makes it great at withstanding some handling and abuse.
It’s made from a non-reactive silicone or latex that won’t suffer or degrade when used with the most common cleaning chemicals. If drywall were to be used in these scenarios, it would crack, wear down, and become powdery, requiring almost constant upkeep.
Caulk is also a pretty flexible material, meaning small movements on surfaces will not cause it any damage. Sealing in drywall edges will move with small foundation shifts and not crack.
Some caulk can be painted and varnished depending on which brand you buy.
Spackle
Spackle is much more akin to putty and great for filling large areas. It dries hard, making it less appropriate for areas that are often subjected to washing/cleaning.
But for walls, it’s excellent as it is durable and can be sanded flat after application. Plus, it can be easily painted.
Once dried, it creates a very similar surface to the drywall in terms of density. If you seal an old screw or nail hole, you can re-screw into that if you wish, and it will be just as secure. Because of caulks soft and more malleable quality, you couldn’t do this.
4. Interchangeability
Caulk
Caulk has many applications beyond its general intended use as an edge sealer.
Because of its airtight nature, it can also be used to seal any drafts around windows. It’s also great for sealing other surfaces, such as stone or metal, to prevent water from getting in and causing problems.
You can even use it in some situations to re-attach wallpaper or roofing tiles.
Spackle
Spackle is a more brittle product when dried, making it harder to use in situations where it may be subjected to water or movement. It will simply chip and break apart.
People have found many creative uses for spackle, so it’s not a complete one-trick pony.
Some people have used spackle with a putty knife for decorative purposes to create a stylized design. It can also be used for decorative stencils to give the ceiling and wall a luxurious trim.
Although these uses are pretty rare, we consider caulk far more interchangeable than spackle.
Caulk vs Spackle: Are they the same?
So although they are both used for filling in gaps, their inherent properties and application methods mean they have substantially different intended uses.
1. Application method
Caulk is usually applied in a thin line using a caulk gun to line the edges of an item. Whereas spackle usually comes in a can or plastic tub and is applied to a flat surface to fill in more significant kinds of gaps.
2. Intended use
Generally speaking, a caulk is designed to seal the gap between two different surfaces, such as a bathtub and the wall or a sink and the countertop.
On the other hand, spackles can fill in larger holes such as a drywall crack, old nail holes, or fissures in drywall.
3. Sealant properties
Caulk is a latex-based sealant (although you can also purchase silicone caulk) and is waterproof, airtight, and can be cleaned without degrading or breaking apart. It’s also quite flexible, making it extra resilient.
Spackle, on the other hand, is quite brittle and not waterproof. , But unlike caulk, it can be sanded down and painted, making it ideal for walls and areas that are not subjected to water constantly.
4. Interchangeability
Despite caulk’s properties making it more appropriate for kitchen and bathroom applications, many people like to use it for small wood-filling jobs, making it quite versatile.
Spackle, on the other hand, is intended for drywall sealing and its inherent properties make it less ideal for situations where the filled area will be subjected to much abuse.
David Kessler is a CSLB licensed contractor with over 25 years of experience. He is specialized in home building, construction, and electrical works; he also has a keen eye for interior design and, over the years, has collaborated with various architects.
