Symptoms
- Wall bulges outward in one section
- Pool looks visibly out of round or oval
- Top rail feels loose or misaligned at a seam
Likely causes
- CommonUneven or settled ground under the pool baseGround that shifts unevenly puts uneven stress on the wall and frame.
- CommonLoose or disconnected top rail or upright supportThe top rail structure keeps the wall's shape; a loose section lets that area bulge.
- PossibleWater level significantly uneven or too low for the frame's designWater pressure helps hold some pool wall designs in shape; running very low can affect this.
- PossibleDamaged or corroded frame componentA bent or rusted upright or top rail section can compromise the wall's support at that point.
What to do
- Check the ground around the base of the pool for any noticeable settling or unevenness near the bulge.
- Inspect the top rail and upright supports near the bulging area for looseness or disconnection and re-secure them.
- Verify the water level is at the manufacturer's recommended height for the pool's design.
- Check the wall track at the bottom for any place it may have popped out of the base track.
- If a specific upright or rail section is bent or rusted through, replace that individual part rather than the whole structure if possible.
- For significant or worsening bulging, consider draining the pool partially to relieve pressure while repairs are made.
Tools and parts
- Wrench or screwdriver (for frame hardware)
- Level
Above ground pool upright/top rail partSearch: “above ground pool frame replacement part”
When to call a pro
A pool installer can assess whether ground releveling or a partial teardown and rebuild is needed for significant structural issues.
Safety
Use caution
A significantly bulging pool wall can be at risk of failure; reduce water level and avoid using the pool until the cause is addressed.