Painting Caulk

What Is Caulk?

Let's start by discussing what exactly is caulk. Caulk, otherwise known as decorators caulk, is a form of sealant that is applied to joints, such as around skirting boards, windows or doors. It is a flexible material that allows the best possible finish to be achieved by covering cracks, removing gaps and generally creating a neat and tidy edge to interior & exterior surfaces. While it is classed as a filler, caulk is not sanded down to create a smooth finish. It is applied using a caulking gun, which dispenses an even line of caulk to the surface.

What Problems Does Caulk Solve?

We have established that caulking helps to leave a perfect finish, but what problems can it solve? Here are a number of the most common uses for caulk when decorating:

• Woodworking - there will always be slight gaps between wood when fitting skirting boards and other pieces of trim. Applying caulk to any joints will allow you to seamlessly join pieces of woodwork without it being noticeable.
• Sticking - caulk can stick surfaces back in place without the need to nails!
• Tiles - tiling used in kitchens and bathrooms can be repaired using caulk, creating a waterproof and mould resistant seal.
• Painting cracks - when covering small hairline cracks, caulk can create a paintable layer on the crack within a matter of hours.
• To seal - windows and other moisture prone areas can be sealed using caulk to prevent gaps for moisture to attack

What Problems Does Caulk Create?

While caulk is an easy to use essential for any decorator, it does create a few issues. There are two main issues with caulk:

• Cracking - caulk is unfortunately prone to cracking, which sometimes occurs when the caulk is not flexible enough for the surface it is filling
• Crazing - when paint is applied over caulk, it can sometimes lead to the paint to peeling & flaking

Cracking

The cracking of caulk is something that is all to common across the UK, causing both DIY'ers and professional decorators a headache. A large number of caulks can crack due one of a multitude of reasons. Ensure the caulk is flexible enough for the surface it is applied to is an easy place to start.

Another all too common cause of caulking cracking is the wrong caulk being used. Caulks like all decorating supplies come in various forms, which makes it imperative to make sure you are using the most suitable caulk for the job. Acrylic caulk can be easily be painted, making it ideal for interior trim such as skirting boards. A silicone caulk is the best option for sealing areas prone to moisture.

Crazing

There are a number of reasons why paint crazing could occur. Firstly, caulk being painted while it is not 100% dry can be a simple explanation. When drying, the caulk will shrink, which can lead to the paint film being compromised due to the movement.

Potentially the biggest cause of paint crazing is the incompatibility of the caulk with the paint used. There are thousands of paints and caulks on the market in the UK today, making it almost impossible to check to compatibility for caulk with paint, which is why it is often suggested to use a primer over the top of caulk before applying paint. This helps to minimise the risk of crazing.

Finally, emulsion being applied too thick can cause it to craze as this will take much longer to dry than a thin coat of paint. Once coated, the moisture will lead to crazing of the thick first coat of paint, lifting the paint off the surface.

How To Solve Cracking Paint Over Caulk

As with every decorating problem, there is always a solution. The particular solution will depend on what caused the cracked paint in the first place, whether wet caulk or paint & caulk incompatibility. Here a few of our experts top tips for preventing paint cracking or crazing on caulk:

1. Do not overapply caulk

Use a thin bead of caulk as over application will increase the likelihood of problems.

2. Ensure you leave you leave the caulk as long as possible to dry

Allowing caulk as much time as possible to dry will eliminate the likelihood of shrinkage causing crazing. Ideally, leave caulk overnight without being coated to be sure. Opting for a quick-drying caulk will also be beneficial.

3. Check paint manufacturers data sheets

This is highly recommended before you start any decorating project. Paint manufacturers will include as much relevant information as possible to ensure that the paint performs to the best of it's ability. Check the data sheet for the paint you are using to see if the paint manufacturer recommends a certain caulk or advise against certain practices.

4. Apply a primer

Priming the caulk before painting is another solution, although it can elongate the decorating process and increase labour costs if you are a professional decorator. A general use primer like Zinsser BIN is perfect of this, helping to create an adhesive layer for the paint to stick to on application and remain adhered to long-term.

5. Check the temperature

In general, water-based paints will be much more likely to crack in temperatures below 8°C. Check the temperature of the room you are applying the paint in before starting.

6. Buy a good caulk

Any caulk is not very expensive, which is all the more reason to buy a good quality caulk. This is more flexible, dries quicker and generally reduces the chance of problems occurring. Buying good quality supplies, whether with paint, caulk or decorating tools is an easy but effective way to achieve the best possible finish. For the small difference in cost, the results can be significant.

The Best Caulk

Here at Painters World we always like to suggest a product that our experts recommend, as we know finding the right product to use can often be difficult.

When it comes to caulk, we highly recommend the Geocel Painters Mate Flexible Filler, which is a flexible acrylic caulk that is ideal for caulking skirting boards, pointing around window and doorframes and filling cracked plaster. It has a quick drying time, allowing it to be overcoated in one hour and contains fungicide to prevent mould growth.

The best part about Geocel Painters Mate is that it is much less prone to cracking when compared to other caulks on the market, which when applied with our expert's recommendations for best practices, will ensure you do not have to deal with cracking or crazing.

• Good value for money
• Great resistance to cracking
• Remains flexible
• Contains a fungicide to prevent mould growth
• Good flow
• Little shrinkage

Frequently Asked Questions

Q. Can you paint over caulking?

So, can you paint over caulking? The answer is yes, as long as you follow the best practices suggested by our experts in this guide. Allow the caulk to dry, use a suitable paint and caulk combination and use a good quality caulk to avoid paint failing when applied to the caulk.

Q. Should you paint before or after caulking?

Ensure the surface is clean & sound before applying the caulk. If required, prime the surface before caulking too, which is essential for bare surfaces. Once caulked, you can then topcoat with paint to create a seamless finish.

Q. Is caulk waterproof?

Silicone caulks are fully waterproof, which is why they are ideal for use in kitchens and bathrooms, such as around baths and tiling.

In contrast, many caulks such as acrylic caulk are designed for use on woodwork such as skirting boards thanks to their ability to be painted. Check the caulk you have opted for in order to see its intended use.

Q. Can you sand decorators caulk?

No, caulk should not be sanded down like you would with a filler due to its flexibility. Many people find that using a wet finger to smooth out the caulk is the best way to get a neat finish. Furthermore, avoiding over applying to caulk will ensure that a neat finish is achieved as it is difficult to remove the caulk from the surface once applied.

We hope this has answered any questions you may have had regarding painting caulk and how to reduce the risk of paint cracking and crazing. If you would like any more help & advice, please feel free to get in touch with one of our experts by emailing hello@paintersworld.co.uk or by sending us a message on social media. Why not shop the range of trade paint, decorating tools & supplies we have in stock here at Painters World, all with FREE next working day delivery on orders over £50.