Pool mastic, also known as caulk, seals the area between the coping and the decking of your pool. No matter how small and invisible it may seem, pool mastic is an important part of your swimming pool. Without it, your pool and decking would be unsealed, which can spell disaster.
Like most other things, pool mastic needs replacing occasionally. But how do you do it? Let’s go over my easy step-by-step process for replacing pool mastic, as well as the cost and signs to look out for.
Main Takeaways
- Remove the old mastic, prep and clean the area, apply the new mastic, smooth it out, and then cure it to replace the pool mastic.
- Some of the signs to look out for that indicate your pool mastic needs replacing include cracks in decking, peeling, tiles falling off, and more.
- You can DIY replace pool mastic, but if you have any doubts, I recommend hiring a professional.
- It costs between $5 to $15 per linear foot to replace pool mastic with the help of a professional.
Step-by-Step Process: How to Replace Pool Mastic
Every now and then, you’ll find that you need to replace your pool mastic. When that day comes, you’ll be happy to learn that mastic is relatively easy to replace as long as you have some DIY knowledge. With my step-by-step process, you should be able to replace your pool mastic in no time.
Step One: Remove the Mastic
Before you can begin applying the new mastic, you’ll need to remove the old mastic. To do so, use a putty knife to scrape it away from the joint. Remove every part of the mastic, using the putty knife and other household tools to clean out the expansion joint.
Step Two: Prep and Clean the Area
After you remove the old mastic, it’s time to properly clean and prep the area for the new mastic. Use a damp cloth to wipe the expansion joint to remove any dust, debris, or even mold. Once clean, make sure the expansion joint is 100% dry before applying the new mastic.
When prepping the area for the new mastic, there is a chance you may need to install a foam backer rod. This is only needed if the expansion joint is too deep. Ideally, the joint should be around the same height and width. So, if it’s too high, install the backer rod before moving on to the next step.
Step Three: Apply the New Pool Mastic
Follow the manufacturer’s instructions to load the caulking gun with the new pool mastic. Then, apply the pool mastic in the expansion joint, making sure to apply as evenly as possible. Work slowly and thoroughly, making sure to avoid any gaps.
Step Four: Smooth It Out
Up until this point, most pool owners should be able to do everything themselves without much of an issue. Where a professional makes a difference is the aesthetics. But even with basic DIY knowledge, try your best to smooth out the mastic so that everything looks neat and tidy. The mastic should be at the same level as the decking and coping.
Step Five: Cure It
Now that the mastic is applied and smoothed out to the best of your abilities, cure it for at least 24 hours. The curing period may be longer, so always read the manufacturer’s instructions for the most accurate information. No one should enter the pool area while the mastic is curing.
Signs That Your Pool Mastic Needs Replacing
So, now you know how to replace the pool mastic. But what signs should you look for that indicate your pool mastic needs to be replaced in the first place?
Separation Between the Coping and Decking
As you know, pool mastic seals the area between the coping and decking. So, if the coping and decking are starting to separate, it’s time to replace the mastic ASAP.
Peeling Mastic
Another telltale sign that your mastic needs replacing is if the mastic is peeling or cracking, which means the mastic is losing its effectiveness. Replace the pool mastic before the issue gets worse.
Other Potential Signs
While these signs don’t necessarily indicate an issue with the pool mastic, it could be a cause of the issue.
Cracks in Decking
Pool mastic allows the decking and coping to expand and contract. So, if you notice cracks in the decking, there could be an issue with the pool mastic not properly absorbing the movements.
Tiles Falling Off
Since pool mastic also helps prevent the concrete from moving around, if the mastic is failing, it could cause your pool tiles to move around and even fall off! While this is not the only cause of tiles falling off, pool mastic failure can be the culprit.
Deck Heaving
Your deck is heaving when the deck rises above the pool due to soil expansion and erosion. Of course, when the deck heaves, the pool mastic might be having issues sealing the expansion joint, so make sure the mastic is still doing its job.
Why Should You Replace Pool Mastic?
But how important is it that you replace the pool mastic when needed? What troubles can occur down the line if you do not replace it in a timely manner? Well, no matter how invisible and small pool mastic is, it plays a very important role in preventing more significant and costly problems down the road.
- It prevents water damage: Pool mastic acts as a barrier that prevents water from getting into the pool deck. If the mastic is failing and water gets in, it can cause the deck to shift or crack.
- It maintains structural integrity: Pool mastic allows the coping and decking to expand and contract in response to temperature changes. If you do not replace failing mastic, this expansion and contraction can lead to extensive damage to not only the coping and decking but also the pool itself.
- It extends your pool’s lifespan: Tying into the above, keeping your pool and pool area in good condition will extend the lifespan of your pool. Timely replacement of pool mastic can help lessen the wear and tear on your decking, coping, and pool.
- It improves aesthetics: Peeling or cracking pool mastic simply does not look good. Plus, old mastic tends to become discolored or stained. Fresh and well-applied pool mastic gives your pool area a clean and well-maintained look.
Pool Mastic Replacement: DIY or Hire a Professional?
Replacing pool mastic might seem like a straightforward DIY project, especially if you’re handy with tools and enjoy playing handyman at home. But, although the steps involved seem easy, applying the mastic with expert hands is much more difficult than it may seem. Mistakes can lead to inadequate sealing, which might result in water damage, potentially costing more in repairs down the line. Plus, it can be fairly difficult to apply the mastic evenly, which could ruin the aesthetics of your pool.
If you are confident in your abilities to apply the mastic evenly and expertly, going the DIY route can save you money. But if you have any doubt at all, in my opinion, it’s worth hiring a professional simply for the peace of mind of knowing that the job will be done correctly and efficiently. Professionals can also provide warranties, which protect you further.
Pool Mastic Replacement Cost
The cost of replacing pool mastic depends on a couple of different factors:
- The size of your pool, and
- Whether you choose to do the job yourself or hire a professional.
On average, pool owners can expect to pay between $5 and $15 per linear foot for professional mastic replacement, which typically includes removing old mastic, cleaning the joints, and applying the new mastic. This means that for a pool with a perimeter of around 100 feet, you will be paying anywhere between $500 and $1,500 for pool mastic replacement.
On the flip side, if you go the DIY route, you can obviously expect to pay much less, as you’ll just need to cover the materials. You’ll need to buy pool mastic, a caulking gun, a putty knife, and a foam backer rod.
Get My Free Pool Care Checklist
Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.
Frequently Asked Questions
How often does pool mastic need to be replaced?
This depends on various factors, but generally, you will need to replace your mastic every 1 to 10 years. Check your mastic every month for any signs of failure.
How long does it take for pool mastic to dry?
After applying the mastic, let it cure for about 24 hours or according to the manufacturer’s instructions. Make sure no one enters the swimming pool area while the mastic cures.
Check the Mastic
Pool mastic may be such a small part of the grand scheme of your pool, but don’t underestimate how important its role is in protecting your pool, coping, and decking. Always keep an eye on it, ideally monthly, to ensure the mastic is holding up. And if it shows signs of needing replacing, do so ASAP!
Any more questions regarding swimming pool mastic or pool maintenance in general? Let me know!
