Humidity & Mesh Sagging — Why It Happens

Most mosquito screens soften slightly in warm, humid conditions. This is normal and depends on the mesh material, installation method, and daily temperature swings.

1. Heat Softens Synthetic Fibers

Fiberglass and polyester both become more flexible as temperatures rise. This reduces tension and creates small ripples or waves across the surface.

2. Moisture Adds Weight to the Mesh

Humid air absorbs into the fibers, increasing weight. Even a small increase causes the center of the mesh to drop slightly.

3. Daily Expansion & Contraction

Cooler nights tighten synthetic mesh. Hot, humid afternoons loosen it again. This cycle creates gradual relaxation over time.

4. Why Some Screens Sag More Than Others

• Fiberglass: Softens most; prone to ripples.
• Polyester: Holds tension better; moderate sagging.
• Aluminum: Almost no sag; rigid and stable.

5. What to Do

• Ensure the mesh was not stretched too tightly during installation.
• Re-seat the spline (for framed screens) if long-term sagging occurs.
• Check that magnets or adhesive strips have not lifted from heat.

Humidity-related softening is normal. A properly installed screen should tighten again once temperatures drop.

Related Guides

• Mosquito Screen Mesh Types Explained
• Window Mosquito Screen Installation Guide
• Door Mosquito Screens: Fit & Stability Guide
• Back to Mosquito Screens hub

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