Pool covers can shrink due to excessive heat, UV exposure, chemical damage, or improper storage. Most shrinkage occurs with vinyl and mesh covers, while solid safety covers are more resistant but not immune.
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Yes, pool covers can shrink, and it's more common than many pool owners realize. Heat exposure, UV radiation, chemical imbalances, and improper storage are the primary culprits. Vinyl covers and mesh safety covers are most susceptible, while high-quality solid safety covers offer better resistance. The good news is that shrinkage is largely preventable with proper care and maintenance.
Different cover materials respond differently to environmental stressors. Vinyl covers are the most prone to shrinkage because the material becomes less flexible over time when exposed to temperature extremes. Standard blue tarp-style covers can shrink significantly – sometimes losing 6-12 inches in length or width over a single season.
Mesh safety covers also experience shrinkage, particularly in the webbing and fabric portions. The polypropylene or polyethylene materials used in these covers can contract when exposed to prolonged heat and UV radiation.
Solid safety covers with reinforced vinyl and strong perimeter webbing are more resistant but not immune. High-quality covers from manufacturers like Loop-Loc, Meyco, or Coverstar use UV-stabilized materials that resist shrinkage better than budget alternatives.
Extreme temperature changes cause cover materials to expand and contract repeatedly. When covers are stretched tight during hot weather and then exposed to cold temperatures, the material can lose its elasticity and remain in a contracted state. This is especially problematic in regions with significant seasonal temperature variations.
Prolonged sun exposure breaks down the polymer chains in synthetic cover materials. As UV rays degrade the material, it becomes brittle and loses its original dimensions. Covers left on pools during hot summer months without UV protection are particularly vulnerable.
High chlorine levels, improper pH balance, and chemical spills can accelerate cover deterioration. When pool water with excessive sanitizer levels contacts the cover regularly, it can cause the material to break down and shrink. Chlorine levels above 5 ppm or pH levels outside the 7.2-7.8 range increase this risk significantly.
Storing covers in hot attics, garages, or direct sunlight during off-season periods accelerates aging and shrinkage. Folding covers too tightly or storing them while damp also contributes to material degradation.
Keep your pool's chemistry balanced when the cover is in contact with water. Maintain free chlorine between 1-3 ppm, pH between 7.4-7.6, and total alkalinity between 80-120 ppm. Test water weekly and adjust as needed using a quality test kit like the Taylor K-2006C.
Remove covers during extremely hot weather when possible, especially lightweight vinyl covers. If you must leave the cover on during heat waves, ensure it's not stretched too tightly. Allow some slack to accommodate thermal expansion.
Use UV protectant sprays designed for vinyl and synthetic materials. Products like 303 Aerospace Protectant can extend cover life significantly when applied according to manufacturer directions – typically every 3-4 months during active use periods.
Don't over-tension your cover during installation. Safety covers should be snug but not drum-tight. Excessive tension puts unnecessary stress on the material and hardware, increasing shrinkage risk.
Measure the shrinkage by comparing current dimensions to original specifications. Minor shrinkage (1-3 inches) might be manageable with adjustment, while significant shrinkage (6+ inches) typically requires professional evaluation or replacement.
For safety covers, contact your installer or manufacturer. Many companies offer re-measurement and adjustment services. They can sometimes add material sections or relocate anchor points to accommodate moderate shrinkage.
For winter covers, consider using cover clips or water bags to secure areas that no longer reach the pool edge properly. This isn't ideal long-term but can extend the cover's usable life by one season while you plan for replacement.
Replace covers that have shrunk more than 6 inches in any direction, show signs of brittleness or cracking, or no longer provide adequate safety protection. Attempting to stretch severely shrunk covers can cause tears and compromise safety.
Consider repair for high-quality safety covers with minor shrinkage, especially if they're less than 5 years old. The investment in professional adjustment often makes financial sense compared to full replacement.
When purchasing new covers, invest in UV-stabilized materials with reinforced construction. Look for warranties that specifically address shrinkage – reputable manufacturers stand behind their products' dimensional stability.
Safety Warning: Never attempt to forcibly stretch a shrunk safety cover to fit anchor points. This can cause catastrophic failure and pose serious safety risks.
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