Pool Owner’s Guide on Pool Caulking

If you own a pool, or are building a new pool, you will want to read this guide. Pool Caulking is designed to give you the best information on how to caulk your pool.

If you own a swimming pool, then your pool caulk may be due for repair or replacement. Pool caulking refers to the caulk used to seal the junction between your pool coping and the existing decking around your pool.

Suppose you reside in an area that gets cold. Pool caulking helps prevent freezing water (or extreme heat) from damaging the foundation of your swimming pool. During freezing temperatures, concrete can contract and expand. The caulk joint, on the other hand, absorbs this contraction in the concrete.

However, when and why should you replace your pool caulk, and how frequently should it be repaired? In this article, we provide answers to your most pressing questions about pool caulking.

Ready? Let’s dive in.

What Does Pool Caulking Do?

Close up of a hand pool caulking using a caulk gun

Ice is one of the most powerful natural forces on the planet. When water freezes, it expands dramatically. Ice can burst through steel, concrete, rock, and just about anything else that stands in its path. Second, concrete also expands in warm weather.

Whenever there is a conflict between the vertical pool wall and the horizontal pool deck, which are both expanding, the pool deck is victorious every time.

  • Pool caulking prevents dirt, grit, and other particles from filling the expansion joint and removing expansion space. If this occurs during warm weather, the expanding pool deck will collide with the pool, cracking the pool wall and perhaps loosening the coping stones and tiles.
  • Pool caulking prevents the water from seeping in the rear of the pool wall and behind the coping stones during winter. This can dislodge coping stones and tiles all at once over time.

Aside from keeping your pool wall, tile, and coping from breaking and coming off, new pool caulking looks beautiful, and it comes in various colors: bone, buff, and gray.

Who Needs Pool Caulk?

Swimming pool with brick pavement

Suppose you have a concrete in-ground pool with brick, flagstone, or pre-cast stone copings. Then there’s a huge chance that you have an expansion joint behind the coping stones. This junction provides space for the pool deck to expand when it’s hot outside.

This joint should be caulked every five years or so. If you have cantilever pool decks, then chances are there’s no expansion joint and no need for caulking.

Moreover, most vinyl liner pools or fiberglass pools also don’t usually have an expansion joint. However, some are constructed with brick or stone coping, so there’s space to fill with caulking.

How to Apply Pool Caulk

Step 1: Begin by slicing the old caulk with a sharp razor to remove the build-up.

Step 2: Using a power washer, clean out any dirt or soil that has accumulated in the joint.

Step 3: Fill up any gaps with a foam backer rod and even out the surface.

Step 4: Prepare a Vulkem cartridge. Snip the tip, and start squeezing it into the joint.

Step 5: Make sure to act quickly, so the joint fills up and does not overflow.

Tips on How to DIY Pool Caulking

  • To set the caulking gun down, keep an old cloth in your back pocket and a thick sheet of cardboard with you.
  • You can buy a big-sized caulking gun in the paint area of any home or hardware shop.
  • Keep the dogs and, maybe, the children out of the backyard for the rest of the day. If there is only minimal foot traffic, Vulkem will cure in about 24-48 hours.
  • On porous travertine stones, use Vulkem Primer #191; on metal or plastic surfaces, use TREMprime Primer.
  • Vulkem will stick to moist surfaces but ensure that the joint is completely dry and that the bonding surfaces are clean and grease-free.
  • To achieve the greatest results, use Vulkem pool caulk in temperatures between 50° and 80°.
  • Make sure to clean spills and drips. You can use mineral spirits or xylene for this.

Additional Pool Caulking Tips

A pool with brick style pool coping
  • In making sure you buy just enough caulking, measure the width and depth of your joint accurately.
  • Keep a few small strands of twine ready. This could go handy if there are any ‘runners’ or gaps where caulk could flow through.
  • Self-leveling caulk subsides at the pool’s lowest side or deck and fills in the gaps between them.
  • Dress in old clothing and go slowly around the pool with a piece of cardboard.
  • Don’t tap the deck because it will not stick except on finely cut rocks.

Pool Caulking Essentials

Pool owners know that beneath the clear waters, there’s a lot happening. Pool caulking is a cornerstone in maintaining a pool’s health. It protects, beautifies, and ensures functionality.

Guarding Against Damage

Concrete has a tendency to expand with the sun’s warmth. The damage from neglecting this expansion can be costly. Pool caulking acts as a defender for the expansion joint, shielding it from dirt and grit. Pro tip: Regularly inspect for signs of damage around the joint to catch issues early.

The Role of Sealant

Often termed as mastic or sealant, this substance is vital. Especially for those splash-heavy pool sessions, a sealant protects against rapid deterioration. Using a premium-grade polyurethane sealant is advised for optimal results. After application, give it a full 24 hours to dry.

Choice of Materials Matters

If water sneaks beneath concrete slabs, erosion begins. This can shift your pool deck over time. Hence, picking flexible materials, like concrete-specific caulk, is crucial for durability.

Application: Collaboration is Key

The application process is collaborative. It’s the responsibility of architects, engineers, and pool owners to ensure proper application. Everyone should be on board with the product’s suitability for its purpose.

Edges: More Than Just Aesthetics

The pool’s edges are functional. Proper alignment of caulk with the pool deck and coping edge is essential. Misalignments can lead to those pesky stubbed toes during summer dives. Always remember the importance of the coping connection to the pool’s top edge.

Frequently Asked Questions (FAQs)

How often should pool caulking be replaced?

It varies depending on the caulk’s quality and environmental factors, but generally, pool caulking should be inspected annually and replaced every 2-5 years.

What is the best temperature for caulking a pool?

Ideally, apply caulk in mild temperatures (50-80°F) to ensure proper curing and adhesion.

How long does pool caulk take to dry?

It can take 24-48 hours to dry, but full curing might take up to a week, depending on the product and weather conditions.

What happens if pool caulking is not done correctly?

Improper caulking can lead to water damage, deck shifting, and a higher likelihood of cracks forming.

Are there environmentally friendly caulking options?

Yes, there are eco-friendly caulks available that are less harmful to the environment.

Bottom Line

After completing a DIY inground pool caulking job, it’s time to sit back and enjoy your pool the way it was designed to be enjoyed! Taking care of your expansion joints is well worth the work every few years since it provides you with complete peace of mind that your pool will not fracture or loose tiles for a long time. 

“An ounce of caulk Is worth a pound of prevention.”

Matt, founder of Swim University

Taking the time to repair your pool’s caulking is something that every pool owner should prioritize. The repair process, on the other hand, does not have to be extremely complicated. Just about anybody can finish this job in a few hours if they have access to a supply of high-quality waterproof caulk, measurement equipment, and a little patience. 

I have listed a few more tips and tricks you may find useful in your backyard pool. Do not forget to check them out! To see more articles on pools, click here.

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About the author

Brian Anderson

The rather dry pool world out there is in need of some passion to make it shine. With the help of my son Ruben and his wife Maria our mission is to help you create the favorite spot of your house - your pool.

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