How To Paint Over Silicone Caulk for a Smooth, Long-Lasting Finish  

I recently completed a home makeover and I had the hardest time painting over the silicone caulk I had used in my bathroom and kitchen.

It was only after I searched up “how to paint over silicone caulk” did I realize that most silicone caulk are not paintable!

The thing is hydrophobic, which is great as a seal but the colour mismatch did not work well.

Faced with this scenario, I tested different ideas to see what worked best.

To my dismay, I learned that colored and paintable caulk existed.

At that point, reworking the whole thing would have wasted my money and time.

I tried out primers that could bond well with the silicone caulk.

Zinsser BIN and Kilz, which are shellac and oil based, were my go to choice.

Another option was to use a paintable caulk to create a surface where the paint could stick with ease.

In the following discussion, I aim to give you a step by step breakdown on how to best paint over silicone caulk.

Lets make the hard easy, and get right to it!

What is Silicone Caulk? 

Silicone caulk is a moisture resistant sealant which is commonly used in moisture prone areas like bathrooms, kitchens, and outdoor corners to seal small gaps and leaks.

I chose to use it since I needed something waterproof, durable and long lasting for metal, tile and glass corners.

It started out as a gel and slowly cured into a rubber like solid that did its job. 

It is a flexible and adhesive sealant made from silicone polymers which is best used on non-porous surfaces like I’ve mentioned above.

Its formulation includes low, medium to high modulus which cures moisture. 

Understanding Modulus

Modulus is the degree of stiffness or flexibility of the caulk.

For the purpose of my home project, I used a high modulus silicone caulk which is best for joints and corners that see minimal movement.

Here is where I will stress the importance of choosing the right modulus for your use.

Low modulus for the areas with a higher measure of movement, like doors, windows, etc for its flexibility and elasticity.

The medium one balances both flexibility and strength, and its uses are similar to low modulus. 

Application

Applying the caulk was an easy process.

You have to clean the area properly and tape the sides with painter’s tape to get good edges.

Silicone caulk comes in a cartridge or tube, and an applicator gun plus smoothing tool.

You need to cut the nozzle of the product at a 45 degree angle and when applying it to the joint, pull the gun with a steady hand at a 45 degree angle. 

Smoothing Out

The smoothing out process is just as simple.

You can wet your finger with soapy water or alcohol and just smooth out the excess.

Using a smoothing tool works just as well. I used a damp hand towel to clean the area of any remaining product.

This is something you have to do immediately after application as you will require mineral solvents or spirit if the silicone caulk dries. 

Cure

The curing process, simply put, is a waiting game.

It takes 24 hours to a couple more days for the silicone caulk to dry depending on the thickness of your application.

You have to wait for it to completely dry before you can use water or paint on the area. 

Aside from my vexations with its non-paintable nature, I have to accept the value of silicone caulk.

It has great adhesion, and sealing my tubs, sinks and showers with it was rewarding.

To state again, silicone caulk really is waterproof and moisture resistant.

I got the durability I wanted since it handles temperature fluctuations quite well. 

A Step By Step Guide on: How to Paint over Silicone Caulk 

All projects require a method and a process.

Let me explain how you can paint over Silicone Caulk without having to sweat over the methods.

The process will make you sweat, but let’s work together for the best results. 

Cleaning

If your silicone is fully cured, you can begin your project.

Clean the silicone thoroughly with alcohol.

Any residue like oil or dirt will conflict with the task.

I stress this as it is easy for the primer or paint to not adhere well as the silicone itself is already hydrophobic. 

Sanding the Silicone

Silicone is rubbery once cured, and I gently sanded down for the slight imperfections I missed while smoothing it out during application.

Use a 100 or 120 grit sandpaper for this task.

The process of sanding will allow a smooth finish for the primer to adhere to.

But be warned that this could affect the integrity of its moisture resistance. 

Taping

You can use a painters tape to cover the edges of the area you want to paint over.

We will be masking off the area so there are no uneven spills.

Even a steady hand requires support for better results. 

Applying A High Adhesive Primer

Prepare your shellac or oil based primer since it bonds better with silicone.

You can use it as a spray on or a simple paint brush will do.

Apply more than one coat at a time and make sure it dries well.

In my hurry, I found that using a hair dryer worked but I do suggest letting it air dry normally to avoid any mishaps. 

Sanding the Primer 

After your primer is dry, you can gently sand it to smooth with a 220 grit sandpaper.

The aim is to get it to look even and lightly scratch the surface for better adhesion when you apply your topcoat.

Paint over the Primed Caulk 

Now, you can simply pick your color of choice and get to work.

Note that you have to clean any residue left over after sanding your primer before you start on this step.

Always ensure that your primer is thoroughly dry because your primer can easily be deformed if you are not careful.

How To Paint Over Silicone Caulk on different materials?

Silicone repels paint.

A fact I would have enjoyed knowing before I started on my project.

This meant that simply trying to paint over the silicone caulk was a fruitless task as the paint never adhered to the material. 

When beginning my spiral into the best way to paint over silicone caulk, I was met with more failures than success.

I had to find a way to make the paint adhere and my first answer was to use a primer over the silicone caulk. 

Note that we have to choose an oil or shellac based primer for this job.

For example, shellac based BIN or oil based Kilz. 

On Wood

My first dilemma began when I was considering how to paint over silicone caulk on wood.

For the wooden corners of my cupboards in the kitchen, I sprayed an oil based primer over the silicone before applying the topcoat.

This is something I mimicked for the window panel on the outside which was already treated with a sealant where the paint was bubbling and crawling off.

If you are struggling with how to paint over silicone caulk on the outside, this method will help. 

In Bathroom/In Shower 

Moisture prone areas were the hardest to work with.

I mulled over how to paint over silicone caulk in bathroom, and had to get a little more handsy.

Since I opted out of the laborious process of removing the silicone, I found a way to place paintable caulk over silicone caulk.

Ideally, we can pick between hybrid polymer sealant or a paintable silicone caulk to go over the silicone.

The application process remains the same as discussed in the beginning for silicone caulk, then a thorough cure and primer before topcoat. 

After finishing work on the glass and sinks, I found myself wondering how to paint over silicone caulk in shower since it was more susceptible to water leaks.

To my surprise, the same method bore good results.

I stress that it is important to make sure you have good ventilation to help the drying process.

Interior/Exterior

If you are still wondering how to paint over exterior silicone caulk, let’s look back on how I did it for wood on the outside earlier.

The task is the same but you must ensure one thing, which is to do a thorough cleaning.

Exterior spaces are prone to water damage or mildew, and can be quite dirty.

If you miss this step before applying the primer, the results will be unsatisfactory. 

Interior spaces require the same approach, and we have discussed how I tackled this dilemma earlier.

The ideal choice would have been to use a paintable silicone caulk or acrylic latex caulk from the beginning for interior and exterior jobs.

I will point out one thing here, never opt for regular acrylic caulk to go over silicone since it will not stick to the silicone caulk. 

Old Silicone

If you’ve found yourself dealing with old silicone caulk, it’s best to thoroughly remove and clean the area before applying a new sealant.

But if you insist on knowing how to paint over old silicone caulk, we can indeed paint over it after covering it with primer or paintable caulking. 

Clear Silicone

If you’ve found yourself wondering about how to paint over clear silicone caulk, you are not alone.

This was the true beginning of my labour of love as I worked on my home project.

You can complete the task through a reliable primer like Zinsser BIN or oil based Kilz.

If that is not enough, we will go for paintable caulk over silicone caulk. 

The further discussion will help you understand how to paint over silicone caulk to get a smooth, long-lasting finish. 

Best Way To Paint Over Silicone Caulk 

There are two ways to get the job done.

One method involves using a Primer while the other involves using Paintable Caulk.

Previously, I have discussed where I used these methods.

Now let’s look at what worked best in each process. 

Method of Using Primer 

You can use a shellac based primer like Zinsser BIN or a durable oil based primer in thin coats by ensuring they dry properly between each application.

It is necessary to make sure that the primer you are getting bonds or adheres well with the silicone since the silicone does repel paint. 

This was for the low to medium moisture prone areas like the kitchen cabinets, windows and wooden corners. 

Method of Using Paintable Caulk 

You can use a paintable caulk like urethane or acrylic latex caulk which contains silicone additives to layer over the silicone caulk.

When I say it is a time consuming process, I do mean it.

You can apply it like how I applied the silicone caulk. 

With this method, you have to consider the extent of coverage.

Use a larger bead of paintable caulk over the silicone, and smooth it out over and slightly beyond the surface of the silicone caulk underneath.

Use tape to make sure you get even edges, smooth to finish and wait for it to cure completely before applying your primer of choice.

Follow the step by step guide already discussed above. 

With this, moisture prone areas like your bathroom and sinks should be well guarded from any leaks.

Recommended Solutions on How to Paint Over Silicone Caulk

When searching for how to paint over silicone caulk, the following methods are ones I did not follow but thought to briefly mention. 

The Quick Fix

You can use a hybrid polymer sealant to cover the silicone caulk as it is known to bond well with cured sealants.

They cure moisture like silicone caulk and are paintable.

It has low VOC (volatile organic compounds), is durable and temperature resistant. 

The Reliable Fix

This is the labour intensive process I opted out of. It calls for removing and replacing the silicone caulk.

You can use a caulk removing tool or knife to scrape and cut out the old silicone.

Clean the area thoroughly of any residues before applying the new paintable caulk which can be either urethane or acrylic latex.

Smooth out the caulk, clean excess and wait to cure.

Then rinse and repeat the steps for applying primer and paint. 

Conclusion

So far, we have covered how to paint over silicone caulk.

Two methods can be used: one using the primer as base over the silicone; the other by use of a paintable caulk to cover the silicone.

Though these are not permanent fixes as the most reliable method is to remove and replace the old silicone caulk with a paintable one. 

We have gone through a step by step guide to help you in your project as it did mine, and knowing now that it is paint repellent, you know what not to do.

If you do end up in the same situation as I did, you know your ways around how to paint over silicone caulk.

Follow the guide and get the best home makeover!

Your home projects should be enjoyable and rewarding, so make sure to figure the best needs for your joints and corners before you begin your journey. 

FAQs on How to Paint Over Silicone Caulk