Swimming Pool Blog

Pool Caulking Damage - Repair or Replace?

Repair or Replace Pool Caulking Damage?
by Rob Cox, April 8, 2014

Repair or Replace Pool Caulking Damage?

Before and After pool caulking by Caulking Unlimited, Fred., Md.

Without caulking covering the expansion joint, over time leaves, dirt and sand will fill the joint, removing the room for expansion. In the long term, the pool wall will lose the fight against the horizontal pool deck. Cracking through the beam of the pool, at the tile line could be the eventual result of not maintaining a true and clean expansion joint around the pool.

Another reason for caulking around the pool is to prevent water from freezing in the joint during winter, expanding inside the joint, putting pressure on the pool wall and the pool deck. Again, the pool wall loses the fight. Over years of freeze/thaw cycles, portions of the beam around the pool can crack, a very expensive repair.

This winter has been cold, and that means frost heave for pool decks sitting on wet expansive soils. The term frost heave is when the wet ground under a slab of concrete freezes and lifts the slab, or "heaves" it, I suppose. I wrote an earlier post on the topic of - frost heave on a concrete pool deck.

example of FROST HEAVE, notice the deck is raised over 1 inchIt's not only concrete slab pool decks that heave during hard winters. Custom stone decks can heave the sub-deck, and crack the mortar joints between stones, and of course, rip the caulk joint around the pool. Sometimes slabs settle at different heights, or slide away from the pool, ripping or pulling the caulking away from the edges.

And that is the topic of the day - pool caulking repairs. The caulking joint around the pool is an important part of an inground pool. The caulk covers an expansion joint between the pool and the deck, to allow them both to expand and contract independently, during temperature swings.

How Long Does Pool Caulking Last? 

Generally speaking, it's about 5 years before enough movement and deterioration will need repair or replacement. Sections of your caulking run can last up to 10 years, so it begs the question - Repair or Replace?

If you want to replace just a portion of the caulking, the worst areas, you can simply cut out the old sections with a razor knife, and fill those areas with new caulk. The color will not be exactly the same however, even if you use the same caulk and color. The older caulk will have a faded appearance next to the new caulk.

DIY Caulking vs. Professional Pool Caulking

An experienced caulk professional can caulk circles around any homeowner. Fast, clean and smooth. If you say to yourself, "I've caulked my bathtub, how hard could it be to caulk the pool?" It's not hard, but it is a much larger bathtub, and is indeed more complicated.

Caulk Pros generally use what's called Gun Grade caulking. Mixed on site, it is troweled into the joint by hand to a consistent depth and angle. It's also the only way to caulk vertical joints or a joint where the coping and pool deck are not at the same level. This method is best left to the pros, in my opinion. It's difficult for a novice to tackle, especially with brick coping, or when the pool deck and coping aren't evenly lined up.Poolcenter's pool caulking supplies

Homeowners generally use self-leveling pool caulk. After cleaning the joint and installing backer rod foam to keep the caulk from running down, down, down - a large caulking gun delivers the semi-runny caulk into the joint, where it self-levels and bonds to both sides of the joint - pool deck and pool coping. Self-leveling caulk can be easy to apply, but can't do angles or vertical joints.

If you want to perform some DIY pool caulking on your inground pool, read this post on how to caulk your pool's expansion joint. If you want to have a professional price, search online for swimming pool caulking, and you'll find some local companies who will give you a price per linear foot. The average cost for pool caulking is around $4-6 per linear foot, more if the joint is very wide.

Pool Caulking Tips

  1. Measure your joint width carefully, and buy enough caulk for the job - plus a little extra. 
  2. Use a razor knife carefully to remove all old caulk.
  3. Clean the deck and joint with a powerful blower or pressure washer, to remove debris.
  4. Make sure the joint is completely dry and clean before caulking the pool.
  5. Wear old clothes, move around the pool with a large piece of cardboard.
  6. Lock up the dog and cat for the day. ;-)

 Caulking Unlimited - before and after pool caulking repair

- Rob


Thanks to Caulking Unlimited of Frederick, MD for these great before and after photos of their pool caulking skills.