The gap between your pool structure and surrounding deck is sealed with a flexible joint material commonly known as mastic or Deck-O-Seal®. While this sealant is designed to be durable, it does not last forever.
Over time, worn or cracked mastic can lead to costly structural damage. Pool Rehab provides professional mastic removal and replacement services throughout California and Arizona to protect your pool and extend its lifespan.

When a pool is first constructed, installing mastic is a critical step. It serves as a flexible expansion joint between the pool coping and the surrounding deck. This flexibility allows the two structures to move independently as the pool settles and as temperatures fluctuate.
Without a properly functioning flex joint, the deck and coping can shift together, leading to:
Cracks in the concrete deck
Coping stones shifting out of place
Pool tiles becoming dislodged
Damage to the bond beam or gunite shell
Although the deck and coping may last decades, mastic naturally breaks down much sooner due to weather exposure and seasonal expansion and contraction.
Replacing it at the right time prevents much larger and more expensive repairs later.
Proper mastic replacement requires precision and experience. It’s not simply applying new material over old sealant — it’s a complete removal and reset process.
We begin by carefully cutting out and removing the deteriorated mastic, separating it cleanly from both the deck and the coping. Once removed, we prepare the joint by filling the void with 30-grit sand. This creates a stable, even base for the new sealant to adhere properly.
The new Deck-O-Seal® material is a self-leveling liquid that must be applied with careful timing and attention. Because it cures quickly, our team ensures it is poured evenly without overfilling onto the coping or deck surfaces.
After installation, we apply a final layer of sand over the fresh mastic. This step strengthens the bond and provides a textured finish that blends naturally with surrounding grout lines and deck surfaces.
Temperature changes cause constant expansion and contraction in outdoor concrete. The flexible nature of properly installed mastic absorbs this movement and protects the structural integrity of your pool.
By replacing failing sealant, you’re reinforcing one of the most important protective barriers around your pool and spa.

Mastic replacement is often performed alongside other restoration services such as pool tile cleaning or artificial rock painting. Addressing these elements together creates a cohesive, refreshed appearance while ensuring the structural components are properly protected.
We don’t just improve how your pool looks — we help preserve how it performs.
Mastic replacement demands careful preparation, timing, and attention to detail. Our team provides:
Free, professional on-site estimates
Complete removal of deteriorated material
Proper surface preparation for long-term performance
Clean, precise installation
Clear communication throughout the project
Our focus is protecting your pool today to prevent major repairs tomorrow.

Is Your Pool’s Mastic Cracked or Failing?
Don’t wait for structural damage to occur. Let Pool Rehab professionally remove and replace your Deck-O-Seal® to keep your pool protected and looking its best.

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